[Federal Register: August 24, 2006 (Volume 71, Number 164)]
[Rules and Regulations]
[Page 50121-50192]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr24au06-14]
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Part II
Department of Labor
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Occupational Safety and Health Administration
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29 CFR Parts 1910, 1915, and 1926
Assigned Protection Factors; Final Rule
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DEPARTMENT OF LABOR
Occupational Safety and Health Administration
29 CFR Parts 1910, 1915, and 1926
[Docket No. H049C]
RIN 1218-AA05
Assigned Protection Factors
AGENCY: Occupational Safety and Health Administration (OSHA),
Department of Labor.
ACTION: Final rule.
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SUMMARY: In this final rule, OSHA is revising its existing Respiratory
Protection Standard to add definitions and requirements for Assigned
Protection Factors (APFs) and Maximum Use Concentrations (MUCs). The
revisions also supersede the respirator selection provisions of
existing substance-specific standards with these new APFs (except for
the respirator selection provisions of the 1,3-Butadiene Standard).
The Agency developed the final APFs after thoroughly reviewing the
available literature, including chamber-simulation studies and
workplace protection factor studies, comments submitted to the record,
and hearing testimony. The final APFs provide employers with critical
information to use when selecting respirators for employees exposed to
atmospheric contaminants found in general industry, construction,
shipyards, longshoring, and marine terminal workplaces. Proper
respirator selection using APFs is an important component of an
effective respiratory protection program. Accordingly, OSHA concludes
that the final APFs are necessary to protect employees who must use
respirators to protect them from airborne contaminants.
DATES: The final rule becomes effective November 22, 2006.
ADDRESSES: In compliance with 28 U.S.C. 2212(a), the Agency designates
Joseph M. Woodward, the Associate Solicitor for Occupational Safety and
Health, Office of the Solicitor, Room S-4004, U.S. Department of Labor,
200 Constitution Avenue, NW., Washington, DC 20210, as the recipient of
petitions for review of this rulemaking.
FOR FURTHER INFORMATION CONTACT: For technical inquiries regarding this
final rule, contact Mr. John E. Steelnack, Directorate of Standards and
Guidance, Room N-3718, OSHA, U.S. Department of Labor, 200 Constitution
Ave., NW., Washington, DC 20210; telephone (202) 693-2289 or fax (202)
693-1678. For general inquiries regarding this final standard contact
Kevin Ropp, OSHA Office of Public Affairs, Room N-3647, U.S. Department
of Labor, 200 Constitution Ave., NW., Washington, DC 20210 (telephone
(202) 693-1999). Copies of this Federal Register notice are available
from the OSHA Office of Publications, Room N-3101, U.S. Department of
Labor, 200 Constitution Ave., NW., Washington, DC 20210 (telephone
(202) 693-1888). For an electronic copy of this notice, as well as news
releases and other relevant documents, go to OSHA's Web site (http://www.osha.gov),
and select "Federal Register," "Date of Publication," and then "2006".
SUPPLEMENTARY INFORMATION:
I. General
A. Table of Contents
The following Table of Contents identifies the major preamble
sections of this final rule and the order in which they are presented:
I. General
A. Table of Contents
B. Glossary
II. Events Leading to the Final Standard
A. Regulatory History of APFs
B. Non-Regulatory History of APFs
C. Need for APFs
III. Methodology for Developing APFs for Respirators
A. Introduction
B. Background
C. Methodology, Data, and Studies on Filtering Facepieces and
Elastomerics
D. Alternative Approaches
E. Updated Analyses
F. Summary of Studies Submitted During the Rulemaking
IV. Health Effects
V. Summary of the Final Economic Analysis and Initial Regulatory
Flexibility Analysis
A. Introduction
B. The Rule and Affected Respirator Users
C. Compliance Costs
D. Benefits
E. Economic Feasibility
F. Economic Impacts to Small Entities
VI. Summary and Explanation of the Final Standard
A. Definition of Assigned Protection Factor
B. APF Provisions
C. Assigned Protection Factors for Specific Respirator Types
1. APF for Quarter Mask Air-Purifying Respirators
2. APF for Half Mask Air-Purifying Respirators
3. APF for Full Facepiece Air-Purifying Respirators
4. APF for Powered Air-Purifying Respirators (PAPRs)
5. APF for Supplied-Air Respirators (SARs)
6. APF for Self-Contained Breathing Apparatuses (SCBAs)
D. Definition of Maximum Use Concentration
E. MUCs for Mixtures and Hazard Ratios
F. MUC Provisions
G. Superseding the Respirator Selection Provisions of Substance-
Specific Standards in Parts 1910, 1925, and 1926
VII. Procedural Determinations
A. Legal Considerations
B. Paperwork Reduction Act
C. Federalism
D. State Plans
E. Unfunded Mandates
F. Applicability of Existing Consensus Standards
List of Subjects in 29 CFR Parts 1910, 1915, and 1926
Authority and Signature
Amendments to Standards
B. Glossary
This glossary specifies the terms represented by acronyms, and
provides definitions of other terms, used frequently in the preamble to
the final rule. This glossary does not change the legal requirements in
this final rule, nor is it intended to impose new regulatory
requirements on the regulated community.
1. Acronyms
ACGIH: American Conference of Governmental Industrial Hygienists
AIHA: American Industrial Hygiene Association
ANSI: American National Standards Institute
APF: Assigned Protection Factor
APR: Air-purifying respirator
Ci: Concentration measured inside the respirator facepiece
Co: Concentration measured outside the respirator
DOP: Dioctylphthalate (see definition below)
DFM: Dust, fume, and mist filter
EPF: Effective Protection Factor (see definition below under
"Protection factor study")
HEPA: High efficiency particulate air filter (see definition below)
IDLH: Immediately dangerous to life or health (see definition below)
LANL: Los Alamos National Laboratory
LASL: Los Alamos Scientific Laboratory
LLNL: Lawrence Livermore National Laboratory
MSHA: Mine Safety and Health Administration
MUC: Maximum Use Concentration
NFPA: National Fire Protection Association
NIOSH: National Institute for Occupational Safety and Health
NRC: Nuclear Regulatory Commission
OSHA: Occupational Health and Safety Administration
OSH Act: The Occupational Safety and Health Act of 1970 (29 U.S.C. 655,
657, 665).
PAPR: Powered air-purifying respirator (see definition below)
PEL: Permissible Exposure Limit
PPF: Program Protection Factor (see definition below under "Protection
factor study")
QLFT: Qualitative fit test (see definition below)
QNFT: Quantitative fit test (see definition below)
RDL: Respirator Decision Logic (see definition below)
REL: Recommended Exposure Limit (see definition below)
SAR: Supplied-air (or airline) respirator (see definition below)
SCBA: Self-contained breathing apparatus (see definition below)
WPF: Workplace Protection Factor (see definition below under
"Protection factor study")
TLV: Threshold Limit Value (see definition below)
SWPF: Simulated Workplace Protection Factor (see definition below under
"Protection factor study")
2. Definitions
Terms followed by an asterisk (*) refer to definitions that can be
found in paragraph (b) ("Definitions") of OSHA's Respiratory
Protection Standard (29 CFR 1910.134).
Air-purifying respirator*: A respirator with an air-purifying
filter, cartridge, or canister that removes specific air contaminants
by passing ambient air through the air-purifying element.
Atmosphere-supplying respirator*: A respirator that supplies the
respirator user with breathing air from a source independent of the
ambient atmosphere, and includes SARs and SCBA units.
Canister or cartridge*: A container with a filter, sorbent, or
catalyst, or combination of these items, which removes specific
contaminants from the air passed through the container.
Continuous flow respirator: An atmosphere-supplying respirator that
provides a continuous flow of breathable air to the respirator
facepiece.
Demand respirator*: An atmosphere-supplying respirator that admits
breathing air to the facepiece only when a negative pressure is created
inside the facepiece by inhalation.
Dioctylphthalate (DOP): An aerosolized agent used for quantitative
fit testing.
Elastomeric: A respirator facepiece made of a natural or synthetic
elastic material such as natural rubber, silicone, or EPDM rubber.
Filter or air-purifying element*: A component used in respirators
to remove solid or liquid aerosols from the inspired air.
Filtering facepiece (or dust mask)*: A negative pressure
particulate respirator with a filter as an integral part of the
facepiece or with the entire facepiece composed of the filtering
medium.
Fit factor*: A quantitative estimate of the fit of a particular
respirator to a specific individual and typically estimates the ratio
of the concentration of a substance in ambient air to its concentration
inside the respirator when worn.
Fit test*: The use of a protocol to qualitatively or quantitatively
evaluate the fit of a respirator on an individual.
Helmet*: A rigid respiratory inlet covering that also provides head
protection against impact and penetration.
High-efficiency particulate air filter (HEPA)*: A filter that is at
least 99.97% efficient in removing monodisperse particles of 0.3
micrometers in diameter. The equivalent NIOSH 42 CFR part 84
particulate filters are the N100, R100, and P100 filters.
Hood*: A respiratory inlet covering that completely covers the head
and neck and may also cover portions of the shoulders and torso.
Immediately dangerous to life or health (IDLH)*: An atmosphere that
poses an immediate threat to life, would cause irreversible adverse
health effects, or would impair an individual's ability to escape from
a dangerous atmosphere.
Loose-fitting facepiece*: A respiratory inlet covering that is
designed to form a partial seal with the face.
Negative pressure respirator (tight-fitting)*: A respirator in
which the air pressure inside the facepiece is negative during
inhalation with respect to the ambient air pressure outside the
respirator.
Permissible Exposure Limit (PEL): An occupational exposure limit
specified by OSHA.
Positive pressure respirator*: A respirator in which the pressure
inside the respiratory inlet covering exceeds the ambient air pressure
outside the respirator.
Powered air-purifying respirator (PAPR)*: An air-purifying
respirator that uses a blower to force the ambient air through air-
purifying elements to the inlet covering.
Pressure demand respirator*: A positive pressure atmosphere-
supplying respirator that admits breathing air to the facepiece when
the positive pressure is reduced inside the facepiece by inhalation.
Protection factor study: A study that determines the protection
provided by a respirator during use. This determination generally is
accomplished by measuring the ratio of the concentration of an airborne
contaminant (e.g., hazardous substance) outside the respirator (Co) to
the concentration inside the respirator (Ci) (i.e., Co/Ci). Therefore,
as the ratio between Co and Ci increases, the protection factor
increases, indicating an increase in the level of protection provided
to employees by the respirator. Four types of protection factor studies
are:
Effective Protection Factor (EPF) study: A study, conducted in the
workplace, that measures the protection provided by a properly
selected, fit-tested, and functioning respirator when used
intermittently for only some fraction of the total workplace exposure
time (i.e., sampling is conducted during periods when respirators are
worn and not worn). EPFs are not directly comparable to WPF values
because the determinations include both the time spent in contaminated
atmospheres with and without respiratory protection; therefore, EPFs
usually underestimate the protection afforded by a respirator that is
used continuously in the workplace.
Program Protection Factor (PPF) study: A study that estimates the
protection provided by a respirator within a specific respirator
program. Like the EPF, it is focused not only on the respirator's
performance, but also the effectiveness of the complete respirator
program. PPFs are affected by all factors of the program, including
respirator selection and maintenance, user training and motivation,
work activities, and program administration.
Workplace Protection Factor (WPF) study: A study, conducted under
actual conditions of use in the workplace, that measures the protection
provided by a properly selected, fit-tested, and functioning
respirator, when the respirator is worn correctly and used as part of a
comprehensive respirator program that is in compliance with OSHA's
Respiratory Protection Standard at 29 CFR 1910.134. Measurements of Co
and Ci are obtained only while the respirator is being worn during
performance of normal work tasks (i.e., samples are not collected when
the respirator is not being worn). As the degree of protection afforded
by the respirator increases, the WPF increases.
Simulated Workplace Protection Factor (SWPF) study: A study,
conducted in a controlled laboratory setting and in which Co and Ci
sampling is performed while the respirator user performs a series of
set exercises. The laboratory setting is used to control many of the
variables found in workplace studies, while the exercises simulate the
work activities of respirator users. This type of study is designed to
determine the optimum performance of respirators by reducing the impact
of sources of variability through maintenance of tightly controlled study
conditions.
Qualitative fit test (QLFT)*: A pass/fail fit test to assess the
adequacy of respirator fit that relies on the individual's response to
the test agent.
Quantitative fit test (QNFT)*: An assessment of the adequacy of
respirator fit by numerically measuring the amount of leakage into the
respirator.
Recommended Exposure Limit (REL): An occupational exposure level
recommended by NIOSH.
Respirator Decision Logic (RDL): Respirator selection guidance
developed by NIOSH that contains a set of respirator protection
factors.
Self-contained breathing apparatus (SCBA)*: An atmosphere-supplying
respirator for which the breathing air source is designed to be carried
by the user.
Supplied-air respirator (or airline) respirator (SAR)*: An
atmosphere-supplying respirator for which the source of breathing air
is not designed to be carried by the user.
Threshold Limit Value (TLV): An occupational exposure level
recommended by ACGIH.
Tight-fitting facepiece*: A respiratory inlet covering that forms a
complete seal with the face.
II. Events Leading to the Final Standard
A. Regulatory History of APFs
Congress established the Occupational Safety and Health
Administration (OSHA) in 1970, and gave it the responsibility for
promulgating standards to protect the health and safety of American
workers. As directed by the OSH Act, the Agency adopted existing
Federal standards and national consensus standards developed by various
organizations such as the NFPA and ANSI. The ANSI standard Z88.2-1969,
"Practices for Respiratory Protection," was the basis of the first
six sections (permissible practice, minimal respirator program,
selection of respirators, air quality, use, maintenance and care) of
OSHA's Respiratory Protection Standard (29 CFR 1910.134) adopted in
1971. The seventh section was a direct, complete incorporation of ANSI
Standard K13.1-1969, "Identification of Gas Mask Canisters."
The Agency promulgated an initial respiratory protection standard
for the construction industry (29 CFR 1926.103) in April 1971. On
February 9, 1979, OSHA formally applied 29 CFR 1910.134 to the
construction industry (44 FR 8577). Federal agencies that preceded OSHA
developed the original maritime respiratory protection standards in the
1960s (e.g., Section 41 of the Longshore and Harbor Worker Compensation
Act). The section designations adopted by OSHA for these standards, and
their original promulgation dates, are: Shipyards--29 CFR 1915.82,
February 20, 1960 (25 FR 1543); Marine Terminals--29 CFR 1917.82, March
27, 1964 (29 FR 4052); and Longshoring--29 CFR 1918.102, February 20,
1960 (25 FR 1565). OSHA incorporated 29 CFR 1910.134 by reference into
its Marine Terminal standards (Part 1917) on July 5, 1983 (48 FR
30909). The Agency updated and strengthened its Longshoring and Marine
Terminal standards in 1996 and 2000, and these standards now
incorporate 29 CFR 1910.134 by reference.
Under the Respiratory Protection Standard that OSHA initially
adopted, employers were required to follow the guidance of the Z88.2-
1969 ANSI standard to ensure proper selection of respirators.
Subsequently, OSHA published an Advance Notice of Proposed Rulemaking
("ANPR") to revise the Respiratory Protection Standard on May 14,
1982 (47 FR 20803). Part of the impetus for this notice was the
Agency's inclusion of new respirator requirements in the comprehensive
substance-specific standards promulgated under section (6)(b) of the
OSH Act, e.g., fit testing protocols, respirator selection tables with
assigned protection factors, use of PAPRs, changing filter elements
whenever an employee detected an increase in breathing resistance, and
referring employees with breathing difficulties, either at fit testing
or during routine respirator use, to a physician trained in pulmonary
medicine (see, e.g., 29 CFR 1910.1025 (OSHA's Lead Standard)). The
respirator provisions in these substance-specific standards reflected
advances in respirator technology and changes in related guidance
documents that were state-of-the-art information at the time when OSHA
published these substance-specific standards. These standards
recognized that effective respirator use depends on a comprehensive
respiratory protection program that includes the use of APFs.
In the 1982 ANPR, OSHA sought information on the effectiveness of
its current Respiratory Protection Standard, the need to revise the
standard, and recommendations regarding what revisions should be made.
The 1982 ANPR referenced the ANSI Z88.2-1980 standard on respiratory
protection with its table of protection factors, the 1976 report by Ed
Hyatt from LASL titled "Respiratory Protection Factors" (Ex. 2), and
the RDL developed jointly by OSHA and NIOSH, as revised in 1978 (Ex. 9,
Docket No. H049). The 1982 ANPR asked for comments on how OSHA should
use protection factors. The Agency received 81 responses to this
inquiry. The commenters generally supported revising OSHA's Respiratory
Protection Standard, and provided recommendations regarding approaches
for including a table of protection factors (Ex. 15).
On September 17, 1985, OSHA announced the availability of a
preliminary draft of the proposed Respiratory Protection Standard. This
preproposal draft standard included a discussion of the public comments
received in response to the 1982 ANPR, and OSHA's analysis of revisions
needed in the Respiratory Protection Standard to address up-to-date
respiratory protection. The Agency received 56 responses from
interested parties (Ex. 36), which OSHA carefully reviewed in
developing the proposed rule.
On November 15, 1994, OSHA published the proposed rule to revise 29
CFR 1910.134, and provided notice of an informal public hearing on the
proposal (59 FR 58884). The Agency convened the informal public hearing
on June 6, 1995. In response to the comments OSHA received on the
proposal, the Agency proceeded to develop APFs. On June 15, 1995, as
part of the public hearing, OSHA held a one-day panel discussion by
respirator experts on APFs. The discussion included measuring
respirator performance in WPF and SWPF studies, the variability of data
from these studies, and setting APFs for various types of respirators
that protect employees across a wide variety of workplaces and exposure
conditions.
OSHA also reopened the rulemaking record for the revised
Respiratory Protection Standard on November 7, 1995 (60 FR 56127),
requesting comments on a study performed for OSHA by Dr. Mark Nicas
titled "The Analysis of Workplace Protection Factor Data and
Derivation of Assigned Protection Factors" (Ex. 1-156). This study,
which the Agency placed in the rulemaking docket on September 20, 1995,
addressed the use of statistical modeling for determining respirator
APFs. OSHA received 12 comments on the Nicas report. This report, and
the comments received in response to it, convinced OSHA that more
information would be necessary before the Agency could resolve the
complex issues regarding how to establish APFs, including what methodology
to use in analyzing existing protection factor studies. (See Section IV.
Methodology for Developing Assigned Protection Factors in the June 6, 2003
NPRM, 68 FR 34044, for a detailed discussion of the Nicas report and the
comments OSHA received.)
OSHA published the final, revised Respiratory Protection Standard,
29 CFR 1910.134, on January 8, 1998 (63 FR 1152). The standard contains
worksite-specific requirements for program administration, procedures
for respirator selection, employee training, fit testing, medical
evaluation, respirator use, and other provisions. However, OSHA
reserved the sections of the final standard related to APFs and MUCs
pending further rulemaking (see 63 FR 1182 and 1203). The Agency stated
that, until a future rulemaking on APFs is completed:
[Employers must] take the best available information into
account in selecting respirators. As it did under the previous
[Respiratory Protection] standard, OSHA itself will continue to
refer to the [APFs in the 1987 NIOSH RDL] in cases where it has not
made a different determination in a substance specific standard. (63
FR 1163)
The Agency subsequently established a separate docket (i.e., H049C) for
the APF rulemaking. This docket includes copies of material related to
APFs that previously were placed in the docket (H049) for the revised
Respiratory Protection Standard. The APF rulemaking docket also
contains other APF-related materials, studies, and data that OSHA
obtained after it promulgated the final Respiratory Protection Standard
in 1998.
On June 6, 2003, the Agency published in the Federal Register an
NPRM titled "Assigned Protection Factors; Proposed Rule" (68 FR
34036) that contained proposed definitions for APFs and MUCs, a
proposed Table 1 with APFs for the various respirator classes, and
proposed revisions to the APF provisions and tables in OSHA's
substance-specific standards. The NPRM announced that OSHA would be
holding an informal public hearing in Washington, DC on the proposal.
The public hearings were held over three days, from January 28-30,
2004. OSHA received extensive pre-hearing comments (Exs. 9-1 through 9-
43 and 10-1 through 10-60), written hearing testimony (Exs. 16-1
through 16-25), post-hearing comments (Exs. 17-1 through 17-12), and
post-hearing briefs (Exs. 18-1 through 18-9 and 19-1 through 19-8).
Transcripts of the public hearings also were made and added to the APF
Docket (Exs. 16-23-1, 16-23-2, and 16-23-3). It is from these public
comments, exhibits, hearing transcript, and post-hearing submissions
that OSHA has prepared these final APF and MUC provisions and revisions
to substance-specific standards.
B. Non-Regulatory History of APFs
In 1965, the Bureau of Mines published "Respirator Approval
Schedule 21B," which contained the term "protection factor" as part
of its approval process for half mask respirators (for protection up to
10 times the TLV) and full facepiece respirators (for protection up to
100 times the TLV). The Bureau of Mines based these protection factors
on quantitative fit tests, using DOP, that were conducted on six male
test subjects performing simulated work exercises.
The Atomic Energy Commission (AEC) published proposed protection
factors for respirators in 1967, but later withdrew them because
quantitative fit testing studies, which the AEC used to determine APFs,
were available for some, but not all, types of respirators. To address
this shortcoming, the AEC sponsored respirator performance studies at
LASL, starting in 1969.
ANSI standard Z88.2-1969, which OSHA adopted by reference in 1971,
did not contain APFs for respirator selection. Nevertheless, this ANSI
standard recommended that "due consideration be given to potential
inward leakage in selecting devices," and contained a list of the
various respirators grouped according to the expected quantity of
leakage into the facepiece during routine use.
In 1972, NIOSH and the Bureau of Mines published new approval
schedules for respiratory protection under 30 CFR 11. However, these
new approval schedules did not include provisions for determining
facepiece leakage as part of the respirator certification process.
NIOSH sponsored additional respirator studies at LASL, beginning in
1971, that used quantitative test systems to measure the overall
performance of respirators. In a 1976 report titled "Respirator
Protection Factors", Edwin C. Hyatt of LASL included a table of
protection factors for: single-use dust respirators; quarter mask, half
mask, and full facepiece air-purifying respirators; and SCBAs (Ex. 2).
Hyatt based these protection factors on data from DOP and sodium
chloride quantitative fit test studies performed at LASL on these
respirators between 1970 and 1973. The table also contained recommended
protection factors for respirators that had no performance test data.
Hyatt based these recommended protection factors on the judgment and
experience of LASL researchers, as well as extrapolations from
available facepiece leakage data for similar respirators. For example,
Hyatt assumed that performance data for SCBAs operated in the pressure-
demand mode could be used to represent other (non-tested) respirators
that maintain positive pressure in the facepiece, hood, helmet, or suit
during inhalation. In addition, Hyatt recommended in his report that
NIOSH continue testing the performance of respirators that lacked
adequate fit test data. To increase the database, Hyatt used a
representative 35-person test panel to conduct quantitative fit tests
from 1974 to 1978 on all air-purifying particulate respirators approved
by the Bureau of Mines and NIOSH.
In August 1975, the Joint NIOSH-OSHA Standards Completion Program
published the RDL (Ex. 25-4, Appendix F, Docket No. H049). The RDL
contained a table of protection factors that were based on quantitative
fit testing performed at LASL and elsewhere, as well as the expert
judgment of the RDL authors. In 1978, NIOSH updated the RDL specifying
the following protection factors:
5 for single-use respirators;
10 for half mask respirators with DFM or HEPA filters;
50 for full facepiece air-purifying respirators with HEPA filters or
chemical cartridges;
1,000 for PAPRs with HEPA filters;
1,000 for half mask SARs operated in the pressure-demand mode;
2,000 for full facepiece SARs operated in the pressure-demand mode; and
10,000 for full facepiece SCBAs operated in the pressure-demand mode.
ANSI's Respiratory Protection Subcommittee ("Subcommittee")
decided to revise Z88.2-1969 in the late 1970s. During its
deliberations, the Subcommittee conducted an extensive discussion
regarding the role of respirator protection factors in an effective
respiratory protection program. As a result, the Subcommittee decided
to add an APF table to the revised standard. In May 1980, ANSI
published the revision as Z88.2-1980 which contained the first ANSI
Z88.2 respirator protection factor table (Ex. 10, Docket H049). The
ANSI Subcommittee based the table on Hyatt's protection factors, which
it updated using results from fit testing studies performed at LANL and
elsewhere since 1973. For example, the protection factor for full
facepiece air-purifying particulate respirators was 100 when
qualitatively fit tested, or 1,000 when equipped with HEPA filters and
quantitatively fit tested. The table consistently gave higher protection
factors to tight-fitting facepiece respirators when employers performed
quantitative fit testing rather than qualitative fit testing. The ANSI
Subcommittee concluded that PAPRs (with any respiratory inlet covering),
atmosphere-supplied respirators (in either a continuous flow or pressure-demand
mode), and pressure-demand SCBAs required no fit testing because they operated
in a positive-pressure mode. ANSI assigned high protection factors to these
respirators, but limited their use to concentrations below the IDLH values.
Pressure-demand SCBAs and combination continuous flow or pressure-demand airline
respirators with escape provisions for use in IDLH atmospheres were
assigned protection factors of 10,000 plus.
In response to a complaint to NIOSH that the PAPRs used in a
workplace did not appear to provide the expected protection factor of
1,000, Myers and Peach of NIOSH conducted a WPF study during silica-
bagging operations. Myers and Peach tested half mask and full facepiece
PAPRs under these conditions, and found protection factors that ranged
from 16 to 215. They published the results of their study in 1983
(Ex.1-64-46). The results of this study led NIOSH and other
researchers, as well as respirator manufacturers, to perform additional
WPF studies on PAPRs and other respirators.
NIOSH revised its RDL in 1987 (Ex. 1-54-437Q) to address advances
in respirator technology and testing. The revision retained many of the
provisions of the 1978 RDL, but also lowered the APFs for other
respirators based on NIOSH's WPF studies. For example, the APFs were
lowered for the following respirator classes: PAPRs with a loose-
fitting hood or helmet (reduced to 25); PAPRs with a tight-fitting
facepiece and a HEPA filter (lowered to 50); supplied-air continuous
flow hoods or helmets (decreased to 25); and supplied-air continuous
flow tight-fitting facepiece respirators (reduced to 50).
In August 1992, ANSI again revised its Z88.2 Respiratory Protection
Standard (Ex. 1-50). The ANSI Z88.2-1992 standard contained a revised
APF table, based on the Z88.2 Subcommittee's review of available
protection factor studies. In a report describing the revised standard
(Ex. 1-64-423), Nelson, Wilmes, and daRoza described the rationale used
by the ANSI Subcommittee in setting APFs:
If WPF studies were available, they formed the basis for the
[APF] number assigned. If no such studies were available, then
laboratory studies, design analogies, and other information [were]
used to decide what value to place in the table. In all cases where
the assigned protection factor changed when compared to the 1980
standard, the assigned number is lower in the 1992 standard.
In addition, the 1992 ANSI Z.88.2 standard abandoned ANSI's 1980
practice of giving increased protection factors to some respirators
when quantitative fit testing was performed.
Thomas Nelson, the co-chair of the ANSI Z88.2-1992 Subcommittee,
published a second report entitled "The Assigned Protection Factor
According to ANSI" (Ex. 135) four years after the Z88.2 Subcommittee
completed the revised 1992 standard. In the report, Nelson reviewed the
reasoning used by the ANSI Subcommittee in setting the 1992 ANSI APFs.
Nelson noted that the Z88.2 Subcommittee gave an APF of 10 to all half
mask air-purifying respirators, including quarter mask, elastomeric,
and disposable respirators. The Subcommittee also recommended that full
facepiece air-purifying respirators retain an APF of 100 (from the 1980
ANSI standard) because no new data were available to justify another
value. Nelson noted that the Z88.2 Subcommittee approved the RDL's
reduction to an APF of 25 for loose-fitting facepieces and PAPRs with
helmets or hoods based on their performance in WPF studies. For half
mask PAPRs, the ANSI Subcommittee set an APF of 50 based on a WPF study
by Lenhart (Ex. 1-64-42). The ANSI Subcommittee had no WPF data
available for full facepiece PAPRs, so Nelson indicated that the
Subcommittee selected an APF of 1,000 to be consistent with the APF for
PAPRs with helmets or hoods. The Subcommittee, in turn, based its APF
of 1,000 for PAPRs with helmets or hoods on design similarities (i.e.,
same facepiece designs, operation at the same airflow rates) between
these respirators and airline respirators. Nelson noted that the
results from a subsequent WPF report by Keys (Ex. 1-64-40) on PAPRs
with helmets or hoods were consistent with an APF of 1,000. According
to Nelson, the Subcommittee used WPF studies by Myers (Exs. 1-64-47 and
1-64-48), Gosselink (Ex. 1-64-23), and Que Hee and Lawrence (Ex. 1-64-
60) to set an APF of 25 for PAPRs with loose-fitting facepieces. Nelson
stated that two WPF studies, conducted by Gaboury and Burd (Ex. 1-64-
24) and Stokes (Ex. 1-64-66) subsequent to publication of ANSI Z88.2-
1992, supported the APF of 25 selected by the Subcommittee for PAPRs
with loose-fitting facepieces.
Nelson also stated in his report that the ANSI Subcommittee had no
new information on atmosphere-supplying respirators. Therefore, the
APFs for these respirators were based on analogies with other similarly
designed respirators (Ex. 135). The ANSI Subcommittee based the APF of
50 for half mask continuous flow atmosphere-supplying respirators, and
the APF of 25 for loose-fitting continuous flow atmosphere-supplying
respirators, on the similarities between these respirators and PAPRs
with the same airflow rates. Nelson noted that the ANSI Subcommittee
set the APF of 1,000 for full facepiece continuous flow atmosphere-
supplying respirators consistent with the APF for SARs with helmets or
hoods using the results of two earlier studies: a WPF study by Johnson
(Ex. 1-64-36) and a SWPF study by Skaggs (Ex. 1-38-3). The Subcommittee
used the design analogy between PAPRs and continuous flow supplied-air
respirators to select the APF of 50 for half mask pressure-demand SARs
and an APF of 1,000 for full facepiece pressure-demand SARs. Nelson
stated, "The committee believed that setting a higher APF because of
the pressure-demand feature was not warranted, but rather that the
total airflow was critical" (Ex. 135).
Nelson noted in the report that the Subcommittee selected no APF
for SCBAs. In explaining the committee's decision, he stated that "the
performance of this type of respirator may not be as good as previously
measured in quantitative fit test chambers." Nelson also observed that
the ANSI Z88.2-1992 standard justified this approach in a footnote to
the APF table. The footnote states:
A limited number of recent simulated workplace studies concluded
that all users may not achieve protection factors of 10,000. Based
on [these] limited data, a definitive assigned protection factor
could not be listed for positive pressure SCBAs. For emergency
planning purposes where hazardous concentrations can be estimated,
an assigned protection factor of no higher than 10,000 should be
used.
A new ANSI Z88.2 Subcommittee recently finished revising the ANSI
Z88.2-1992 standard, in accordance with the ANSI policy specifying that
each standard receive a periodic review. This revised ANSI Z88.2
standard is currently under appeal to the ANSI Board.
C. Need for APFs
When OSHA published the final Respiratory Protection Standard in
January 1998, it noted that the revised standard was to "serve as a
`building block' standard with respect to future standards that may
contain respiratory protection requirements" (63 FR 1265).
OSHA's final Respiratory Protection Standard established the minimum
elements of a comprehensive program that are necessary to ensure
effective performance of a respirator. The only parts missing from this
building block standard are the APF and MUC provisions that are being
finalized in this rulemaking. In the standard the Agency recommended
that employers in the interim "take the best information into account
in selecting respirators. As it did under the previous standard, OSHA
itself will continue to refer to the NIOSH APFs in cases where it has
not made specific compliance interpretations" (63 FR 1203).
In October 2004, NIOSH published its Respirator Selection Logic
(RSL), an update of the 1987 RDL. The APF tables in the new RSL have
not changed from those in the 1987 RDL. However, NIOSH stated in the
forward to the 2004 RSL: "[w]hen the OSHA standard on APFs is
finalized NIOSH intends to consider revisions to this RSL." (Ex. 20-
4.)
The ANSI Z88.2-1992 APF table also has been a source for interim
APFs while OSHA completed its APF rulemaking. However, the ANSI Z88.2-
1992 respiratory protection standard was withdrawn by ANSI in 2003.
While a revised ANSI Z88.2 standard has been written, the final ANSI
standard has yet to be published since it is currently under appeal.
Therefore, no ANSI respiratory protection standard with recommended
APFs is available at this time. The draft APF table from the ANSI Z88.2
revision was submitted to the OSHA rulemaking docket (Ex.13-7-2), and
was the subject of discussion during the public hearings on APFs. OSHA
considered the draft ANSI table during its deliberations in this
rulemaking.
Throughout the Respiratory Protection Standard rulemaking, OSHA has
emphasized that the APF and MUC definitions and the APF table are an
integral part of the overall standard. A careful review of the
submitted comments and information supports the Agency's conclusion
that this final standard is necessary to guide employers in selecting
the appropriate class of respirator needed to reduce hazardous
exposures to acceptable levels. The final APF for a class of
respirators specifies the workplace level of protection that a class of
respirator should provide under an effective respiratory protection
program. In addition, the APFs can be utilized by employers to
determine a respirator's MUC for a particular chemical exposure
situation.
The final APFs must be used in conjunction with the existing
provisions of the Respiratory Protection Standard. Integration of the
final APF and MUC provisions into the reserved provisions of paragraph
(d) completes that standard. With the addition of these provisions,
appropriate implementation of the Respiratory Protection Standard by
employers in their workplaces should afford each affected employee the
maximum level of respiratory protection.
III. Methodology for Developing APFs for Respirators
A. Introduction
In the proposed rule for Assigned Protection Factors (APFs), OSHA
raised a number of issues or questions about its proposed methodology
for deriving APFs (68 FR 34112-34113). OSHA asked for information on:
(1) The evidence-based method used by OSHA in developing the proposed
APFs; (2) any additional studies that may be useful in determining APFs
that were not already identified by OSHA in the proposal; and, (3)
statistical analyses, treatments, or approaches, other than those
described in the proposal, available for differentiating between, or
comparing, the respirator performance data. The vast majority of the
comments in response to the NPRM addressed the use of WPF studies for
establishing the APF for filtering facepiece half mask respirators.
OSHA also received comments on the methodology and data it used for
determining the filtering facepiece APF, and was provided with new
studies on these respirators for consideration. OSHA's quantitative
analyses for establishing the APFs for other classes of higher
performing respirators drew little comment, and no new studies on these
respirators were submitted. This section, therefore, focuses on
methodology and new information relative to the APF for half mask air-
purifying respirators.
More specifically, Part C of this section contains a discussion of
the comments about OSHA's proposed methodology for determining APFs for
filtering facepiece half mask respirators, including comments on data
analysis and study selection. In addition, OSHA is providing an
overview of Dr. Kenny Crump's statistical analyses (Ex. 20-1) of the
updated half mask database (Ex. 20-2). Comments about alternative
approaches are discussed in Part D ("Methodology, Data, and Studies on
Filtering Facepieces and Elastomerics"). The Agency's overall
conclusions on methodology, and summaries of new studies submitted
during the public comment process, are presented under Part E.
Discussion of the comments and opinions regarding the APF for half mask
respirators and the establishment of the APFs for higher performing
respirators is included in Section VI, Summary and Explanation of the
Final Standard.
B. Background
The Occupational Safety and Health Act of 1970 ("OSH Act"), 29
U.S.C. 651-678, enacted to ensure safe and healthy working conditions
for employees, empowers OSHA to promulgate standards and provides
overall guidance on how these standards are to be developed. It states:
(5) The Secretary, in promulgating standards dealing with toxic
materials or harmful physical agents under this subsection, shall
set the standard which most adequately assures, to the extent
feasible, on the basis of the best available evidence, that no
employee will suffer material impairment of health or functional
capacity even if such employee has regular exposure to the hazard
dealt with by such standard for the period of his working life.
Development of standards under this subsection shall be based upon
research, demonstrations, experiments, and such other information as
may be appropriate. In addition to the attainment of the highest
degree of health and safety protection for the employee, other
considerations shall be the latest available scientific data in the
field, the feasibility of the standards, and experience gained under
this and other health and safety laws. Whenever practicable, the
standard promulgated shall be expressed in terms of objective
criteria and of the performance desired. 29 U.S.C. 655(b)(5)
[emphasis added].
A reviewing court will uphold standards set under this section when
they are supported by substantial evidence in the record considered as
a whole (29 U.S.C. 655(f)). In searching for the "best available
evidence" upon which to base its rulemaking, OSHA is required to
"identify the relevant factual evidence, * * * to state candidly any
assumptions on which it relies, and to present its reasons for
rejecting any significant contrary evidence or argument." Public
Citizen Health Research Group v. Tyson, 796 F.2d 1479, 1495 (D.C. Cir.
1986).
OSHA has retained the multifaceted approach it used in the proposal
to determine the APFs for classes of respirators. That is, the Agency
reviewed all of the available literature, including the various
analyses by respirator authorities, as well as quantitative analyses of
data from WPF and SWPF studies. During revision of the overall
Respiratory Protection Standard, the Agency used a similar approach
when reviewing protection factor studies related to the effectiveness
and necessity of a comprehensive respiratory protection program.
The Agency did not use Effective Protection Factor (EPF) and
Program Protection Factor (PPF) studies in its APF analyses since these
measure deficiencies in respirator program practices. More
specifically, EPFs are not directly comparable to WPF values because
the determinations include the time spent in contaminated atmospheres
both with and without respiratory protection. PPFs are affected by any
deficient elements of a respirator program, including inadequate
respirator selection and maintenance, poor user training and
motivation, work activities, and inadequate program administration.
Therefore, OSHA relied on WPF and SWPF studies, since they focus on the
performance characteristics of the respirator only.
During the APF rulemaking, OSHA reviewed the extensive literature
on APFs and developed selection criteria for including studies and data
in its quantitative analysis of respirator performance. This procedure
ensured that only carefully designed and executed WPF and SWPF studies
were included in the analysis. The Agency then used these studies to
compile the NPRM's original database. The database was comprised of 917
data points from 16 WPF studies for half mask respirators (Matrix 1)
and 443 data points from 13 studies for PAPRs and SARs (Matrix 2),
conducted in a variety of American workplaces. OSHA made the studies,
its selection criteria, the data, and its analyses available to the
public electronically and through the rulemaking docket. In addition,
the Agency encouraged the public to access this information and to
reanalyze the data using methods of their choice. The Agency also
sought submissions from the public of any additional studies for
inclusion in its database. Four additional WPF studies of half masks
were submitted during the public comment period following publication
of the NPRM. Dr. Kenny Crump updated the Matrix 1 half mask database
with these additional studies (Ex. 20-2) and reanalyzed the resulting
1,339 data points for half mask respirators (Ex. 20-1).
Dr. Crump also performed a second quantitative analysis in which
the 1,339 accepted data points (original NPRM database updated with
data from the four new studies) for half mask respirators were combined
with 403 data points from 12 studies that the Agency originally
excluded from the analysis. This second analysis corroborated the
original findings to the extent practicable. The results of both of
these analyses provide compelling support of OSHA's conclusions
regarding the appropriate APF for half mask respirators. The Agency
believes that the database it constructed represents the best available
data on APFs, and that its conclusions are based on substantial
evidence. See Texas Independent Ginners' Association v. Marshall, 630
F.2d 398, 413 n. 48 (5th Cir. 1980), citing Industrial Union Dept.,
AFL-CIO-CIC v. American petroleum Institute, 448 U.S. 607, 661 (1980).
In past rulemakings, OSHA's conclusions as to the best available
evidence have been upheld as based on substantial evidence when it has
relied on a body of reputable scientific evidence. See ASARCO v.
Occupational Safety and Health Administration, 746 F.2d 483, 494 (9th
Cir. 1984). OSHA need not accept all data presented to it as long it
considers the data and rejects it on reasonable grounds. See id.
Furthermore, each study relied upon by the Agency need not be a model
of textbook scientific inquiry, and OSHA need not find one definitive
study supporting its decision. Public Citizen Health Research Group,
796 F.2d at 1489, 1495. Rather, the Agency is justified in adopting a
conclusion when the cumulative evidence is compelling. Id. at 1489,
1491, 1495. OSHA's conclusions are strongest when it has relied on
multiple data sources that support each other, as it has in this
rulemaking.
C. Methodology, Data, and Studies on Filtering Facepieces and
Elastomerics
1. Comments on the Methodology
OSHA developed the proposed APFs through a multi-faceted approach.
As it stated in the preamble to the proposal, "The Agency reviewed the
various analyses of respirator authorities, available WPF and SWPF
studies, and other APF literature." It later concluded that "the APFs
proposed by OSHA in this rulemaking represent the Agency's evaluation
of all available data and research literature i.e., a composite
evaluation of all relevant quantitative and qualitative information"
(68 FR 34050). OSHA then asked the public if this method was
appropriate to determine APFs. The methodology was supported by a
number of commenters, including NIOSH (Ex. 9-13), the Department of the
Army (Ex. 9-42), ALCOA (Ex. 10-31), and others (e.g., Exs. 9-1, 9-4, 9-
14, 9-16, 9-22, 10-2, 10-17, 10-18, and 10-59). NIOSH stated:
NIOSH agrees that the APF values resulting from this multi-
faceted approach are reasonable indications of the level of
protection that should be expected for each class of respirators. *
* *
The available data are not ideal because there can be
considerable model-to-model variation and only a few models in each
class have been evaluated. Given that lack of complete data, the
approach taken by OSHA is the most appropriate currently possible.
(Ex. 9-13.)
The United States Army Center for Health Promotion and Preventive
Medicine commented:
The method of APF development used by OSHA is appropriate. OSHA
reviewed available data, both published and unpublished; utilized
technical reviews and summaries from subject matter experts outside-
OSHA; weighed study findings and conclusions based on study
shortfalls, as then state-of-the-art technical bias and procedural
omissions; and used a conservative approach to maintain confidence
that minimal risk of respirator selection and use errors will exist
in worker protection from proposed APF use. (Ex. 9-42-1.)
Nevertheless, some commenters did not agree with OSHA's approach.
These participants included several labor organizations (Exs. 9-27, 9-
29, 9-34, 9-40, and 10-37), trade associations (Exs. 9-24 and 10-27),
and individuals (e.g., Exs. 9-17, 9-25, 9-33, 9-41, 10-33, and 10-42).
Criticisms of OSHA's approach focused on the Agency's selection of WPF
studies for its determination of the proposed APFs. Reasons given to
support these criticisms included: The differences between the studies
do not permit comparison of the studies; the study conditions are not
representative of typical workplaces; the study data are too old; the
data do not cover all configurations of filtering facepieces available;
and, the analytical method employed by some studies was too sensitive.
A few commenters (Exs. 10-34 and 10-47) recommended that certain
criteria should be met before a WPF study is deemed acceptable for
analysis. These criteria include: Exposures to small particle sizes;
work time of at least four hours; moderate to heavy work rate; and,
high temperature and humidity. Still others believed that OSHA should
develop and perform SWPFs on a representative subset of all filtering
facepieces or all configurations of filtering facepiece respirators and
all respirator models, and establish APFs for all classes of
respirators based on the SWPF study results (Exs. 9-41 and 10-27). A
more detailed discussion of data issues is presented below.
2. Comments on Data and Study Problems
Selection bias in WPF studies. Several commenters stated that the
authors of WPF studies "cherry-picked" either the workplaces in which
the studies were conducted or the individual tasks that were performed
by workers chosen for monitoring (Pascarella, Tr. at 464; Faulkner,
Tr. at 549 and 564-565). "Cherry-picking" is a common term for
"selection bias." Selection bias is a matter of concern when either
workplace study participants or job tasks are selected for inclusion in
the study in a manner that skews the results of the study away from the
true value.
Selection bias is a matter of concern for all scientific studies,
not just WPF studies, and peer reviewers typically evaluate its effects
before a study is accepted for publication in a peer-reviewed journal.
Most of the studies included in OSHA's analysis of WPF studies were
either published in peer-reviewed journals or were presented at the
AIHCE, and met the criteria for respirator research studies accepted by
the industrial hygiene community. The half mask database consists of 16
studies performed in a variety of workplaces over a range of years
(from 1976 to 2004) by many different researchers. Therefore, it is
highly improbable that these studies were subject to selection bias.
OSHA could find no instance of selection bias either in its review of
the scientific studies or its analysis of the data. Finally, OSHA
repeatedly asked commenters who raised concerns about "cherry-
picking" for specific studies in which selection bias occurred. In no
case did the commenters provide any details to support their
allegations.
Observer effect in WPF studies. Several commenters (Shine, Tr. at
644 and Macaluso, Tr. at 652) stated that data from the WPF studies
considered by OSHA were the result of a condition known as the
"observer effect." The observer effect occurs when the act of
observing or monitoring test subjects causes their responses to differ
from their usual (nonobserved) responses. In some of the WPF studies
used by OSHA, the researchers stated that during the study, they were
present to monitor the test equipment to ensure that the sampling
equipment functioned properly, thereby increasing the usefulness of the
results. In other WPF studies, the researchers did not indicate their
presence during the study.
The mere presence of an observer does not, in and of itself,
presume that there will be an observer effect. For example, if the
observer is a researcher who is monitoring the test equipment instead
of a supervisor who is monitoring the workers' practices, the workers
are unlikely to change their practices.
Although the Agency repeatedly asked the commenters who raised this
concern to identify specific studies in which the observer effect may
have been involved, they could not do so (i.e., in no case did the
commenters provide any example to support their allegations). In its
own analysis of the WPF studies, the Agency was also unable to find any
evidence of an observer bias.
Representativeness of the data. A number of commenters expressed
concern that the study data analyzed by OSHA were not representative of
conditions found in the construction industry (Ex. 9-29, Building
Construction Trades Department), or of workplace conditions in general
(e.g., Exs. 9-34, International Union Operating Engineers; 9-35,
Melissa Rich; 9-40, United Steel Workers of America; and 10-60, Paul
Hewett). The bulk of these concerns are represented in the comments of
Melissa Rich, a Department of Energy respirator program manager, who
stated:
The selection of the test sites for the cited APF proposed
rulemaking WPF studies are not representative of the worksite for
American workers. Many test sites chosen for these studies were
selected on availability only. Moreover, key study attributes such
as hot humid conditions, long work hours, and heavy workload were
the exception, not the norm for most of the cited studies. Most test
sites had ambient concentrations less than the OSHA half mask
respirator maximum use limit (i.e., ten times the PEL).
* * * * *
The various particle sizes, a critical issue in a WPF, cited in
many of the APF proposed rule Workplace Protection Factor studies
are so large that they do not penetrate the faceseal. Many
respiratory protection studies have indicated that particles larger
than two microns are less likely to penetrate the most important
attribute of a respirator, the faceseal. Most of the APF proposed
rule Workplace Protection Factor studies have a particle size
greater than two microns. (Ex. 9-35.)
The studies analyzed by OSHA consisted of a varied cross-section of
workplaces and conditions. For example, workplaces included ship
breaking, asbestos removal, aluminum and lead smelters, brass
foundries, and aircraft painting and manufacturing. Two of the four new
studies analyzed by OSHA involved concrete-block manufacturing. The
authors of an aluminum smelter study (Ex. 1-64-24) noted that employees
were required to rest in a cool area for 50% of each hour due to high
heat, and a steel mill study (Ex. 1-64-50) and a primary lead smelter
study (Ex. 1-64-42) both were conducted in the sinter plant and blast
furnace areas. The asbestos study (Ex. 1-64-54) was conducted under
high humidity conditions. Tasks performed by test subjects included
welding and grinding, torch cutting, pouring molten metal, handling
concrete blocks, and spray painting. Work rates for these studies, when
provided, ranged from low to heavy.
The purpose of a WPF study is to evaluate a respirator's
effectiveness under actual workplace use conditions. Consequently, the
contaminant concentrations and particle sizes contained in the analyzed
studies were generated while the workers performed their normal job
duties. With regard to concerns about particle size, Myers et al.
(Ex.1-64-51) found particles larger than 10 microns inside the
respirator facepiece. The Agency believes that accepting only WPF
studies that are conducted at exposure levels close to 10 times the
PEL, with particulates of two microns in size or less, would not be
representative of the conditions found in the workplace. Studies based
on such selective criteria would be more akin to a SWPF, rather than a
WPF, study. OSHA has concluded that the data used in its analyses are
applicable to other American work settings because a range of work
rates and environmental conditions were represented, and many of the
tasks performed by the test subjects are performed in a variety of
workplaces, including construction. Accordingly, the Agency is not
persuaded by comments suggesting that the studies were so narrowly
focused that the data cannot be applied to other work settings.
Sensitive analytical method. Several commenters questioned the use
of sensitive analytical methods for the analyses of workplace
exposures, sometimes accompanied by a recommendation to test
respirators under controlled laboratory settings, and at sufficiently
high concentrations to obtain inside-the-facepiece measurements (Ci)
that can be assessed by less sensitive methods (e.g., Exs. 9-32, 9-35,
10-6, 10-37, and 10-49). The commenters believed that sensitive
analytical methods (particularly PIXEA, proton-induced x-ray emission
analysis) permit the determination of low Ci concentrations, resulting
in high protection factors.
In response to these comments, OSHA reviewed the seven half mask
studies that used the PIXEA analytical method (Exs. 1-64-19, 1-64-51,
1-64-52, 1-64-15, 1-64-16, and 1-64-34) and found that six of the
studies used the method to measure both the Ci and Co concentrations.
The seventh study (Ex. 3-12) used PIXEA to measure the Ci concentration
but used atomic absorption (AA) to assess Co concentrations because the
respirator filters were overloaded. However, the Agency does not believe
that this study provided inaccurate results. Under conditions of high Co
concentrations, the AA method must be used because the PIXEA method would
exceed its maximum measurement limits. Therefore, the PIXEA method would
be unable to provide accurate Co data. Based on its review of these seven
studies, the Agency found that the sensitive analytical method (i.e., PIXEA)
allowed the investigators to quantify small amounts of contaminant that
penetrate a respirator. This method permitted accurate assessment of Ci
concentrations under conditions of low ambient concentrations, thereby
permitting the use of actual Ci values in determining WPFs. Less sensitive
methods would result in penetration values that are nondetectable or less
than the limit of detection (LOD) for the analytic method, thereby requiring
the study to discard these data or to correct for nondetected values using
unvalidated statistical techniques. On the other hand, the sensitive
analytical method was able to quantify low Ci concentrations, thereby
enhancing the validity of the subsequent analysis by retaining the
actual data and avoiding unvalidated statistical corrections.
Craig Colton of 3M provided the following testimony in support of
OSHA's conclusions:
Some commenters also asserted that the use of analytical methods
with low detection limits are a reason to invalidate some of the WPF
studies. The claim is erroneously made that the analytical
sensitivity affects the results from WPF studies. However, the
actual amount of contaminant on the Ci sample is not changed by the
analytical method.
* * * Because the [Ci levels are] typically very small in a WPF
study, the higher sensitivity of [the PIXEA method] is necessary to
get the best data.
* * * The WPF protocol from the AIHA Respirator Committee
recommended the use of analytical methods with sensitive detection
limits. * * * Use of less sensitive analytical methods for * * *
[Ci] sample[s] that result in nondetect values are not meaningful
for determining true exposure. (Tr. at 413-414.)
In its post-hearing comments, 3M illustrated the value of sensitive
analytical methods using the following example:
[C]onsider three filters "spiked with 1 [mu]g of silicon each
and analyzed by three different methods [gravimetric, atomic
absorption (AA), and PIXEA]. In the case of gravimetric and AA
analyses, it is certain only that the silicon mass on the filter is
between 0 [mu]g and 10 [[mu]g] or 0 [mu]g and 5 [mu]g respectively.
However, PIXE[A] has sufficient analytical sensitivity to "find"
the true value of 1 [mu]g. Because the mass of contaminants on a Ci
filter is typically very small in a WPF study, the higher
sensitivity of PIXE[A] is necessary to get the best data. (Ex. 19-3-
1.)
Tom Nelson commented that "[t]he analytical method must be
sensitive for a WPF study. For a half facepiece respirator[,] the
detection limit should be at least \1/100\ of the ambient
concentration" (Ex. 18-9). Later in these comments, Nelson stated,
"The [low-concentration Ci] samples are part of the distribution of
WPF samples collected during a study. These represent true measures of
performance."
Based on the evidence in the record, OSHA concludes that using
sensitive analytic methods for assessing Ci samples is both necessary
and appropriate. Specifically, the Agency sees no scientific basis for
excluding WPF studies that used PIXEA, particularly when using the
method to determine both Ci and Co. The Agency's review of the record
evidence shows that a leading national organization representing
industrial hygienists (i.e., the AIHA) recommends using sensitive
analytic methods for assessing Ci samples. Furthermore, using sensitive
analytic methods improves significantly the validity of data analyses
by allowing studies to retain low Ci values, and by reducing
substantially the need to use unvalidated techniques to correct low Ci
values. Therefore, OSHA concludes that the data from the WPF studies
used in its analyses are accurate, and that the availability of data
with low Ci values improved the validity of the APFs derived from these
analyses.
Large particles. Several commenters (e.g., Exs. 9-33, 9-35, 10-6,
10-37, and 10-41) postulated that larger particles (greater than one or
two microns) do not penetrate a respirator's faceseal. They believed
that WPF studies having large particles in the Co concentration should
be excluded from OSHA's analyses. They reasoned that these large
particles were being measured as part of the Co but had no chance of
being measured in the Ci, and consequently were inflating the WPF
values.
These commenters appear to be ignoring the possibility that half
masks (both elastomerics and filtering facepieces) with faceseals that
selectively filter large particles still are capable of providing an
adequate level of protection. Nevertheless, OSHA notes that in one of
the WPF studies used in OSHA's data analyses, Myers et al. found large
particles (i.e., 10 microns in diameter) inside the facepiece,
indicating that large particles are capable of penetrating a respirator
faceseal (Ex. 1-64-51). Consistent with these results, Tom Nelson
stated in his comments that "[t]he particle size of contaminants in
the various WPF studies in the docket range from [about] 0.5 [microns]
to 14 [microns] MMAD," and that "particles much larger than those
that would be predicted from laboratory studies have been found inside
the facepiece in WPF studies" (Ex. 18-9). At the hearing, Nelson
presented data showing that large particles enter half mask
respirators, probably through breaks in the faceseal; moreover, these
data demonstrate that no relationship exists between particle size and
the WPF obtained for the respirator (Tr. at 146-148). The 3M Company
addressed this point further, stating in its comments:
Laboratory studies have shown that particle losses occur through
fixed leaks. A faceseal leak is not accurately represented by a
fixed leak, however. To perform these studies[,] assumptions were
made regarding leak size, shape, and the particle size penetrating
those leaks. These assumptions have been shown to be wrong. Myers
has shown that large particles can be found inside the facepiece[,]
much larger than could have occurred with the fixed leaks used by
several researchers.[] As shown in Figure 1 [of the Myers et al.
study], an analysis of particle size and the geometric mean WPF from
a number of studies does not show any relationship between particle
size and WPF. If the size of the particle played a role in faceseal
leaks, a relationship would be evident. (Ex. 9-16.)
Based on the evidence in the record, OSHA concludes that the data
in its APF analyses for half masks were the same as particle sizes
found in the workplaces represented in the WPF studies. Therefore,
eliminating the study data from the Agency's analyses would be
unnecessary and inappropriate.
Probe bias. Probe bias refers to the misplacement of the sampling
probe when taking measurements inside the respirator facepiece. Some
commenters expressed concern that probe bias may have underestimated Ci
in the half mask WPF studies analyzed by Dr. Brown (e.g., Exs. 9-17, 9-
30, 9-35, and 10-42). These commenters suggested that OSHA reanalyze
its database after applying a correction factor to account for probe
bias. Tim Roberts provided a specific description of this concern when
he testified:
Respirator probe error is an issue. It's been better
characterized for elastomeric type respirators than it has for
filtering facepiece respirators, and we think that this needs some
additional work as well, to characterize what that means when we put
probes in different locations in elastomeric facepieces (Tr. at
208).
Later in the hearings, Ching-tsen Bien questioned Craig Colton of
3M on Colton's experiences with probe location while conducting
filtering facepiece WPF studies. Colton responded:
[S]treamlining that you see is similar to that in the
elastomeric half-facepieces. You see it streamlining from the leak
up to the mouth and nose. And so what Dr. Myers indicated in his
sampling bias--not really probe bias, but the sampling bias--was
that location becomes important because if your probe is flushed
with the facepiece, you can miss the streamlines. So his
recommendation was that the probe needs to be ideally on the
midline, between the mouth and the nose, and as close to the face as
possible. And so that's what we attempt to do as best as you can
with the products you end up testing to meet his recommendations.
(Tr. at 455-456.)
Colton also noted that, although some of his studies may show
probes entering the side of the filtering facepiece, a probe extension
was used to place the sampling inlet in the nose-mouth area (Tr. at
455-456). Tom Nelson explained the purpose of the probe location when
he commented, "The sampling probe is placed so that it is close to the
nose and mouth. This minimizes sampling bias" (Ex. 18-9). Warren Myers
testified that, in unusual circumstances, the configuration of a half
mask (including some elastomerics) requires placing the sampling probe
on the side of the mask instead of the centerline between the nose and
the mouth; in these cases, a study can control for sampling bias by
randomly alternating the location of the probe on the right and left
side of the mask (Tr. at 77).
OSHA also reviewed the 13 half mask studies analyzed by Dr. Brown.
The authors of nine of these studies specifically state that the probe
was located in the area of the nose and mouth. While the remaining four
studies do not specify the probe's location, no evidence from this
rulemaking indicates that the sampling probes were inappropriately
placed. Therefore, the majority of the WPF studies, along with the new
studies included in the updated database, located the sampling probe in
the nose-mouth area. Of the 1,339 data points in the updated database,
approximately 220 of these points (about 16%) are from the four studies
in which no information on probe placement was available. OSHA believes
the sampling methodology that was used in these studies was consistent
with comments indicating that the optimum location for a probe is at
the centerline between the nose and the mouth. At this location, the
probe will sample any streamlining that occurs between a faceseal leak
and the nose-mouth area, thereby detecting the maximum Ci exposure
level. In addition, no analysis was submitted indicating that the data
from these studies, whether corrected for probe bias or excluded
altogether, would have resulted in APFs that differed from the final
APFs derived from this rulemaking.
3. Summary and Conclusion
OSHA considered the comments addressing the data and study problems
identified by commenters, but does not find that these comments merit
rejection of the data or analyses. The studies OSHA analyzed were
conducted on employees in actual workplaces who were performing their
normal job duties. Consequently, the particle sizes, work rates, work
times, and environmental conditions varied among these studies. The
Agency has concluded that using data collected under these various
conditions presents a more accurate picture of workplace use of these
respirators and is a better measure of the protection provided by half
mask respirators than data collected only from SWPF or other highly
controlled studies.
D. Alternative Approaches
1. Alternatives Based on Non-Compliant Respirator Programs
Several commenters suggested alternative means for ascertaining
APFs. While not completely disagreeing with OSHA's approach, Paul
Hewett of Exposure Assessment Solutions Incorporated (Ex. 10-60) stated
that OSHA should include EPF studies in its APF deliberations. He
commented that EPF studies account for actual use conditions in that
they factor in the time that the employee does not wear the respirator
but is still exposed to atmospheric contaminants. He also believed that
determination of an appropriate APF should represent respirator use in
hot, strenuous jobs. Therefore, he recommended that "OSHA should
factor in real world conditions and not rely exclusively on WPF and
particularly SWPF studies" (Ex. 10-60.)
OSHA noted in the proposal that the Agency would analyze only WPF
and SWPF studies since they address respirator performance exclusively
(68 FR 34045). This alternative approach already has been addressed
above by the Agency in its discussion of the usefulness of WPF data.
The Agency has no data in the record showing that EPF studies would
improve, or even complement, its analyses. Therefore, OSHA is not
convinced that EPF data would increase the validity of the APFs derived
in this final rule. The discussion of an EPF study by Harris et al.
(Ex. 27-11; 63 FR 1167) substantiates these conclusions.
Ching-tsen Bien of LAO Consulting, Inc. (Ex. 18-5) wanted OSHA to
enter into the record any available independent assessment reports (and
applicable check lists) for the year prior to, and for the year of,
each WPF study. Bien noted that the reports would have covered
applicable program elements, and ensure that OSHA selected studies for
its analyses that were in compliance with appropriate respiratory
protection standards. He also requested that OSHA enter the "selection
criteria, decision matrix for each study, and the review report for
these studies to the H-049C Docket" (Ex. 18-5.)
As stated in the NPRM at 68 FR 34046, the Agency evaluated all
studies used in its analyses for compliance with the requirements of
OSHA's Respiratory Protection Standard (29 CFR 1910.134), as well as
for completeness of the data. The Agency also compiled a list of
criteria (Ex. 5-5) for evaluating each study. Accordingly, OSHA
evaluated each published article or each written study report to
determine whether the test subjects were trained properly, fit tested,
medically evaluated, and in compliance with the requirements of the
OSHA Respiratory Protection Standard. The researchers performing these
WPF studies ensured that fit testing was performed on the test
subjects, trained them on doffing and donning the respirator, as well
as the performance of user seal checks, on the selection of proper-
sized respirators, and on the other elements of a complete OSHA-
compliant respirator program. These researchers did not rely on the
existing workplace respirator program, but instead performed the
necessary actions to ensure that the test subjects in their WPF studies
met the respirator program requirements.
The WPF studies the Agency evaluated were either WPF studies that
had been published previously, or were newly performed studies that
were submitted during the rulemaking for inclusion in the OSHA
database. OSHA did not perform these studies, and was not involved in
the selection of the worksites being tested. Therefore, the Agency
could not gather additional information on a worksite's respirator
program that was in effect when a WPF study was performed, as Bien
requested. Additionally, such information is irrelevant to the results
of a WPF study since the researchers had to demonstrate compliance with
the required respirator program before OSHA included the study in its
database.
2. Alternatives Based on SWPF Studies
The American Chemistry Council (Ex. 10-25) stated that OSHA's APFs
should be based on SWPF studies, and that the APFs derived from this
rulemaking should be used only as interim values until SWPF studies
could be performed. OSHA notes that basing APFs on SWPF studies, rather
than on WPF studies, was recommended by a number of commenters
including Organizational Resource Counselors Worldwide (ORC) (Ex. 10-
27), Paper, Allied-Industrial, Chemical & Energy Workers International
Union (PACE) (Ex. 10-37), and others (e.g., Exs. 9-32, 9-41, 10-6, 10-
49, 9-33, 9-35, and 18-5). These commenters expressed various concerns
about the WPF studies, and stated that SWPF studies permit
investigators to control a number of variables (e.g., particle size,
contaminant concentration, environmental conditions) that cannot be
controlled in WPF studies.
SWPF studies use sensitive analytical methods, such as PIXEA, to
obtain measurable Ci information. SWPF studies safely test a respirator
in a high-concentration atmosphere (i.e., at the respirator's limit of
protection) to generate enough penetration for the analytical method to
quantify Ci results. OSHA agrees that SWPF testing permits an
investigator to control factors such as particle size, contaminant
concentration, temperature, and humidity. Accordingly, the Agency used
data generated from all available SWPF studies in determining APFs.
However, OSHA concluded that controlled SWPF studies alone are not
representative of, nor can they be extrapolated readily to, typical
workplaces. Standardized protocols for conducting such testing, or a
methodology for extrapolating SWPF results to protection levels
expected in the workplace, are not available. ORC stated, "We advocate
development of a protocol based on a combination of laboratory testing
and field trials for determining expected respirator performance" (Ex.
10-27). NIOSH also supported the use of both SWPF and WPF studies,
noting, "NIOSH agrees that the APF values resulting from OSHA's
multifaceted approach to analysis of existing data provide reasonable
values for the level of protection that should be expected for each
class of respirators" (Tr. at 102). NIOSH continued, "Given this lack
of complete data, the noted model-to-model variation and the
imperfection in protection level measurements, the approach taken by
OSHA is the best currently possible based upon available data" (Tr. at
103). The Agency has concluded that its approach in using both WPF and
SWPF studies is well supported by the rulemaking record and is
appropriate for determining APFs specified in this final rule.
3. Model-Specific APFs
The Organization Resources Counselors Worldwide (Ex. 10-27), the
American Chemistry Council (Ex. 10-25), and the Pharmaceutical Research
and Manufacturers of America (Ex. 9-24) urged OSHA to develop model-
specific APFs. Under this recommendation, each respirator model would
undergo testing and be assigned a unique APF. NIOSH did not support
this approach. In response to questioning by OSHA, NIOSH stated:
This morning's expert witnesses and the questions I think
clearly identified that there is variability, and because of this
variability, we believe that class APFs are more appropriate and
consistent with the state of the art today. In order to achieve more
precise data, much, much larger data sets, including the numbers of
test subjects that would have to be involved to eliminate this
variability, seems impractical based upon the state of the art
today. So we are for these reasons supporting class APFs, not model-
specific APFs. (Tr. at 120.)
OSHA considered the use of SWPF studies in developing model-
specific APFs. The Agency's review of the ORC SWPF study of PAPRs and
SARs in the proposal (68 FR 34069) stated that ORC had recommended that
"the [ORC SWPF] study methodology should be the basis for determining
APFs for all respiratory protective equipment regulated by OSHA" (68
FR 34070). However, only a few SWPF studies are available that measured
the performance of a few PAPRs and SARs. Model-specific SWPF studies
for the remaining respirator classes have not been performed. In
addition, the respirator protection community has not agreed on a
standard protocol for conducting SWPF studies, or how the results
relate to APFs. These issues would have to be addressed before it would
be possible to use model-specific APFs. Also, insufficient data are
available to set model-specific APFs, and developing the methodology
and conducting the testing could take years. OSHA believes that
completing the APF rulemaking with the information available now is
necessary. Delaying this rulemaking to develop model-specific APFs will
result in employers not knowing what respirators to select and,
consequently, employees will not receive adequate protection. Based on
the rulemaking record, the Agency has concluded it will determine an
APF for each respirator class using information from existing WPF and
SWPF studies.
4. Nicas-Neuhaus Model
Several commenters (Paul Hewett, Ex. 10-60; Bill Kojola, AFL-CIO,
Ex. 17-2; and NIOSH, Ex. 17-7-1) asked OSHA to consider a February 2004
article by Nicas and Neuhaus (Ex. 17-7-2) that applies a model for
analyzing WPF data to establish APFs. The Nicas-Neuhaus article is
based on the variability of WPFs (i.e., the variability between
different test subjects, as well as the variability within a test
subject resulting from repeated donnings of the respirator). APFs based
on this Nicas-Neuhaus model require that WPFs for 95% of all workers be
above the APF 95% of the time. However, the established method for
deriving APFs used by OSHA, NIOSH, and ANSI sets the APFs at the 95%
percentile of the between-subject WPFs. By controlling for within-
subject variability, APFs based on the Nicas-Neuhaus model will always
be smaller than APFs derived using the established method.
To account for within-subject variability, the Nicas-Neuhaus model
requires repeated measurements on each test subject which is not
required by the established method. Consequently, most available WPF
studies did not include multiple measures on individual test subjects,
resulting in an extremely limited database for applying the Nicas-
Neuhaus model. Nicas and Neuhaus were able to analyze only seven half
mask respirator studies, comprising a total of 310 data pairs. In
comparison, the database established and analyzed by OSHA for
determining the final APFs contains 1,339 data pairs from 16 half mask
respirator studies. Also, OSHA had rejected for its analyses several of
the WPF studies used by Nicas and Neuhaus in developing their model
because these studies did not meet the Agency's selection criteria.
The Nicas-Neuhaus model is a significant departure from established
and accepted practices used by the respirator research community, The
Agency has concluded that there are insufficient data to fully evaluate
the proposed model, and to incorporate it in setting APFs.
5. Other Alternative Approaches
Sheldon Coleman recommended that OSHA select a panel from AIHA
members to review the APF data and OSHA's APF determinations (Ex.10-
40). OSHA believes this rulemaking has provided ample opportunity for
comment from the public and professional associations. Further analysis
would delay the development of the final APFs, and is unnecessary as
the rulemaking record is sufficient to determine APFs.
6. Summary and Conclusion
OSHA is relying on science, data, and established quantitative
analyses to establish the final APFs for filtering facepiece and
elastomeric half mask respirators, and is limiting its statistical
analyses to those procedures that use the selected data to the fullest
extent possible. Reliance on alternative approaches is not supported by
the evidence in the record. The data to use such approaches are not
currently available, and require either a different set of data or a
standardized testing protocol that requires testing every respirator
model. OSHA concludes that the available data and analytic methods used
in determining the final APFs are appropriate.
E. Updated Analyses
1. Review of the Original WPF and SWPF Databases
In developing its proposed rule regarding APFs for respirators,
OSHA contracted with Dr. Kenneth Brown to investigate possible
approaches for evaluating respirator performance data from WPF and SWPF
studies. To assist Dr. Brown in this evaluation, the Agency reviewed
the available studies and created a database from these studies. In
deciding which WPF studies to include in this database, OSHA evaluated
studies with respect to compliance with the requirements of its
Respiratory Protection Standard (29 CFR 1910.134) and the completeness
of the data. In doing so, the Agency excluded WPF studies of gas or
vapor contaminants due to the limited number of these studies and the
difficulties in conducting and interpreting data from such studies (68
FR 34046). During the rulemaking, OSHA received new WPF data on half
mask respirators. No new SWPF data were submitted for half masks, and
no new WPF data were submitted for higher-performing respirators.
In the NPRM, Dr. Brown initially divided negative pressure half
mask air-purifying respirators (APRs) into five classes. Four classes
of filtering facepiece half masks were derived based on whether a
respirator had adjustable head straps, an exhalation valve, a double-
shell construction, or a foam-ring faceseal. Elastomeric half masks
were grouped together in a single fifth class. (See Ex. 5-1 for details
on respirator class definitions.) In his analyses, Dr. Brown found no
clear evidence of a difference in WPFs across these different classes.
In particular, he found that elastomeric half masks performed
substantially the same as filtering facepieces. From the original
database of 917 WPF measurements for negative pressure half mask APRs,
36 WPF measurements (3.9%) were found to have an APF less than 10, and
96.1% at 10 and above.
2. Updated OSHA Database on APRs
In the NPRM, OSHA asked if any more WPF or SWPF studies should be
considered in setting APFs. Data from four additional studies were
submitted for OSHA's evaluation during the comment period, and an
updated half mask database was compiled using these studies (Ex. 20-2).
During the post-hearing comment period, the 3M Company provided OSHA
with data from two additional WPF studies of filtering facepiece
respirators. One study (Colton and Bidwell, Ex. 9-16-1-1) measured the
performance of three different types of filtering facepiece respirators
used by 21 workers at a lead-battery manufacturing plant. One
respirator (3M 8710) was approved under 30 CFR part 11, and two
respirators were N95 particulate respirators (3M 8210 and 3M 8510)
approved under 42 CFR part 84. Up to three WPF measurements were made
with each worker on each respirator type, for a total of 143 WPF
measurements. The data submitted to OSHA from this study are provided
in Appendix A of Dr. Crump's report on the reanalysis of the half mask
database (Ex. 20-1).
The second set of WPF data provided by 3M Company was from a study
by Bidwell and Janssen (Ex. 9-16) on the performance of a "flat-fold"
filtering facepiece respirator conducted at a concrete-block
manufacturing facility. Repeated measurements of WPFs were made on 19
workers, and each sample was analyzed for both silicon and calcium. A
total of 73 Co and 73 Ci air samples were collected, for a total of 146
WPF measurements. Eleven of the 146 Ci measurements were non-detectable
(all coming from silicon exposures).
The third study added to the database was a WPF study by Colton
(Ex. 4-10-4) on the performance of an elastomeric half mask respirator.
This study had been submitted earlier to OSHA, but was not included in
the NPRM database since it was received too late for inclusion in Dr.
Brown's original analysis. The data from this study, conducted in the
battery-pasting and assembly areas of a battery manufacturing plant,
have now been added to OSHA's updated database. Also, three additional
data points from a study by Myers and Zhuang (Exs. 1-64-50 and 3-14)
were added to the updated database. These data were collected in a
concrete-block facility while elastomeric half mask respirators were
worn as protection against calcium and silicon particulates.
The updated OSHA half mask database (Ex. 20-2), summarized in Table
III-1, contains 1,339 WPF measurements--760 collected from filtering
facepiece respirators, and 579 from elastomeric respirators. The
database originally analyzed by Dr. Brown contained 917 WPF
measurements--471 from filtering facepieces, and 446 from elastomerics.
Table III-1.--Summary of OSHA WPF Database for APRs
--------------------------------------------------------------------------------------------------------------------------------------------------------
Number Number
Respirator class Figure 1 Constituent sampled Author Exhibit No. samples per samples per
No. study class
--------------------------------------------------------------------------------------------------------------------------------------------------------
Filtering Facepiece Respirators
--------------------------------------------------------------------------------------------------------------------------------------------------------
1....................................... 1 Asbestos................... Dixon..................... 1-64-54 26 474
1....................................... 2 Fe......................... Myers..................... 1-64-50, 3-14 21 ...........
1....................................... 3 Mn......................... Wallis.................... 1-64-70 69 ...........
1....................................... 4 Al......................... Colton.................... 1-64-15 23 ...........
1....................................... 5 Al......................... Johnston.................. 1-64-34 13 ...........
1....................................... 6 Si......................... Johnston.................. 1-64-34 15 ...........
1....................................... 7 Ti......................... Johnston.................. 1-64-34 18 ...........
1....................................... 8 Pb......................... Colton & Bidwell.......... 9-16-1-1 143 ...........
1....................................... 9 Si......................... Bidwell & Janssen......... 9-16 73 ...........
1....................................... 10 Ca......................... Bidwell & Janssen......... 9-16 73 ...........
3....................................... 11 Pb......................... Myers..................... 1-64-51, 3-12 19 162
3....................................... 12 Zn......................... Myers..................... 1-64-51, 3-12 20 ...........
3....................................... 13 Fe......................... Colton.................... 1-146 31 ...........
3....................................... 14 Mn......................... Colton.................... 1-146 32 ...........
3....................................... 15 Ti......................... Colton.................... 1-146 28 ...........
3....................................... 16 Zn......................... Colton.................... 1-146 32 ...........
4....................................... 17 Pb......................... Colton.................... 1-64-16 62 124
4....................................... 18 Zn......................... Colton.................... 1-64-16 62 ...........
--------------------------------------------------------------------------------------------------------------------------------------------------------
Elastomeric Respirators
--------------------------------------------------------------------------------------------------------------------------------------------------------
5....................................... 19 Asbestos................... Dixon..................... 1-64-54 46 579
5....................................... 20 B(a)Pyrene................. Gaboury................... 1-64-24 18 ...........
5....................................... 21 Pb......................... Lenhart................... 1-64-42 25 ...........
5....................................... 22 Pb......................... Myers..................... 1-64-51, 3-12 46 ...........
5....................................... 23 Zn......................... Myers..................... 1-64-51, 3-12 46 ...........
5....................................... 24 Fe......................... Myers..................... 1-64-50, 3-14 30 ...........
5....................................... 25 Cr......................... Myers..................... 1-64-52, 4-5 35 ...........
5....................................... 26 Ti......................... Myers..................... 1-64-52, 4-5 33 ...........
5....................................... 27 Cd......................... Colton.................... 1-64-13 68 ...........
5....................................... 28 Pb......................... Colton.................... 1-64-13 57 ...........
5....................................... 29 Pb......................... Dixon & Nelson............ 1-64-19 42 ...........
5....................................... 30 Pb......................... Colton.................... 4-10-4 130 ...........
5....................................... 31 Calcium.................... Myers..................... 1-64-50, 3-14 3 ...........
---------------------------------------------------------------------------------------------------------------
Grand Total......................... ........... ........................... .......................... .............. ........... 1339
--------------------------------------------------------------------------------------------------------------------------------------------------------
3. Variability of the APF Data
Several commenters (Faulkner, Ex. 9-40 and Kojola, Ex. 9-27)
criticized WPF studies because the studies demonstrated what they
considered to be a high degree of variability of the data. However, it
is inappropriate to describe the variability of the data with terms
such as "high" or "low" because no recognized standard exists by
which to characterize variability. The variability of the data should
reflect the true variability in respirator fit and performance
experienced by workers who wear respirators. It is reasonable to expect
variability because respirator performance is determined by many
factors, including: Respirator type, the workers' face shapes, work
practices and effort levels, and workplace conditions such as
temperature and humidity. Thus, the key issue is not whether the data
have too much or too little variability, but whether the variability in
the data reflects the true variability in respirator performance under
actual workplace conditions.
A logarithmic transformation was applied to the WPF data set to
adjust for a skewed distribution and extreme outliers, both of which
are common with ratio-based data. As Figure III-1 shows, when a
logarithmic transformation is applied to OSHA's WPF database, the data
closely follow a standard normal distribution. Therefore, OSHA's
analysis of the data, which assumes that WPFs are log-normally
distributed with a geometric mean of 307 and a geometric standard
deviation of 7.1, appropriately accounts for the variability in the WPF
data.
4. Analysis of Updated Database on APRs
OSHA proposed an APF of 10 for negative pressure half mask APRs,
including both filtering facepieces and elastomerics (68 FR 34096).
Accordingly, the present analysis focuses on estimating this APF,
particularly the percent of WPFs that are less than 10.
Figure III-2 displays the 1,339 WPF values, grouped by respirator
class,\1\ study, and contaminant. Each column of data points in the
figure corresponds to a row number listed in column 2 of Table III-1.
This figure shows that more WPFs for elastomerics are less than 10 than
was the case for filtering facepieces, even though a much larger
proportion of these WPFs are from filtering facepieces.
---------------------------------------------------------------------------
\1\ Includes four of the five classes originally determined in
the analysis conducted for OSHA by Dr. Ken Brown; no data were
available for Class 2. Dr. Brown characterized disposable half marks
according to combinations of the following four design
characteristics: (1) Adjustable head straps, (2) presence of an
exhalation valve, (3) double shell construction, and (4) foam ring
liner. Class 1 has none of the four design characteristics. Class 2
has design characteristics (1) and (3). Class 3 has design
characteristics (1) through (3). Class 4 has all four of the design
characteristics. Class 5 consists of all elastomeric half masks.
---------------------------------------------------------------------------
Figure III-2 also shows that differences exist between WPFs
measured in different studies, even among respirators of the same type.
For example, both the Colton (Ex. 1-64-15, 4 in Figure 2) and
the Colton and Bidwell (Ex. 9-16-1-1, 8 in Figure 2) studies
were conducted by some of the same investigators, and both studies used
Class 1 filtering facepieces. Nevertheless, all but one of the 23 WPFs
in the Colton study (Ex. 1-64-15) are less than 40, while all 143 of
the WPFs from the Colton and Bidwell study (Ex. 9-16-1-1) are at least
58 or higher. However, the Colton study evaluated respirators approved
under 30 CFR part 11, whereas the Colton and Bidwell study evaluated
respirators approved under 42 CFR part 84.
Table III-2 shows the percentages of WPFs less than 10 by
respirator class, along with the 90% statistical confidence intervals
on these percentages. The exact confidence intervals are based on a
binomial distribution for counts. The percentage of WPFs less than 10
is less than 5% for all four classes, and the 90% statistical
confidence interval on this percentage excludes 5% for every class
except elastomerics. Also, elastomerics had the highest percentage of
WPFs less than 10 (4.5%). Over all classes, 38/1339, or 2.8%, of WPFs
were less than 10 (90% confidence interval: 2.1%, 3.7%). The upper
bound of this two-sided 90% confidence interval, 3.7%, is equivalent to
a one-sided 95% upper statistical confidence bound on the true
proportion of WPFs less than 10. This bound may be interpreted as
follows: assuming the database is representative of workplace WPFs in
general (more specifically, that the data approximate a random sample
of WPFs from all workers who use respirators), when the true proportion
of WPFs less than 10 is 3.7%, the probability of observing 2.8% or less
(the observed percentage) would be 1 - 0.95 = 0.05. Thus, under these
assumptions, it is unlikely that the true proportion of WPFs less than
10 is as high as 3.7% (and extremely unlikely to be as high as 5%).
Table III-2.--Percent of WPFs Less Than 10 by Respirator Class
----------------------------------------------------------------------------------------------------------------
Total n n < 10 Percent (90% Cl)
----------------------------------------------------------------------------------------------------------------
Class 1................................................ 474 11 2.3 (1.3%, 3.8%)
Class 3................................................ 162 0 0.0 (0.0%, 1.8%)
Class 4................................................ 124 1 0.8 (0.0%, 3.8%)
Class 1-4 (Filtering Facepieces)....................... 760 12 1.6 (0.9%, 2.5%)
Class 5 (Elastomerics)................................. 579 26 4.5 (3.2%, 6.2%)
--------------------------------------------------------
Total.............................................. 1339 38 2.8 (2.1%, 3.7%)
----------------------------------------------------------------------------------------------------------------
In the earlier database analyzed by Dr. Brown, 3.9% of the WPFs
were less than 10. By comparison, among the 422 WPFs added to the
database, only \2/422\ (0.5%) were less than 10. Thus, the new data
indicate a higher level of protection by APRs.
In addition to the 1,339 WPFs in the updated OSHA database, an
additional 403 WPFs from 12 studies were coded by OSHA but were not
included in either the present database or the one analyzed by Dr.
Brown. These data were omitted for various reasons, including too few
WPF measurements in a study and problems with the quality of the
studies (i.e., study did not meet requirements of OSHA's Respiratory
Protection Standard). In addition, as noted earlier, OSHA did not
include data from studies in which exposures were predominantly to a
gas or vapor. To determine the effect that excluding these data had on
the results in Table III-2, the 403 WPFs were added to the updated data
base of 1,339 WPFs (for a total of 1,742 WPFs), and the overall
fraction of WPFs less than 10 was computed (Table III-3). The percent
of WPFs less than 10 was 4.0% (90% confidence interval: 3.2%, 4.8%).
Thus, even with no data exclusions, the overall percent of WPFs smaller
than 10 is less than 5%, and the 95% statistical upper confidence bound
is also less than 5% (i.e., 4.8%).
Table III-3.--Comparison of Percent of WPFs Less Than 10 in Studies Used and Not Used by OSHA
----------------------------------------------------------------------------------------------------------------
Total n n < 10 Percent (90% Cl)
----------------------------------------------------------------------------------------------------------------
Used................................................... 1339 38 2.8 (2.1%, 3.7%)
Unused................................................. 403 31 7.7 (5.6%, 10.2%)
Both Used and Unused................................... 1742 69 4.0 (3.2%, 4.8%)
----------------------------------------------------------------------------------------------------------------
Consistent with the WPF studies used in its analysis, OSHA adopted
the point estimate of the lower 5th percentile of WPF or SWPF data to
establish APFs. Table III-4 shows the point estimate of the 5th
percentiles of WPFs for different categories of respirators using the
updated database. The 5th percentile of WPFs for filtering facepieces
as a whole was 18.1, and for elastomerics it was 12.0. In both cases,
the point estimate was above the APF of 10 proposed by OSHA. Since
several commenters expressed concern about whether sufficient evidence
is available to support an APF of 10 for filtering facepieces, OSHA
also calculated 90% confidence intervals for each point estimate. (As
noted earlier, the lower limit estimate of a two-sided 90% confidence
interval is equivalent to a one-sided 95% lower confidence bound.) The
lower 95% confidence bounds for the 5th percentile of WPFs exceeded 10
for all classes combined, and, with the exception of elastomerics, for
each individual class. The confidence limits for the 5th percentiles
were computed using the method for distribution-free confidence
intervals of Hahn and Meeker (1991), as implemented in SAS (2001).
Therefore, OSHA concludes that sufficient statistical evidence is
available to justify an APF of at least 10 for filtering facepieces.
Table III-4.--Fifth Percentiles of WPFs by Respirator Class
------------------------------------------------------------------------
5th
percentile (90% Cl)
------------------------------------------------------------------------
Class 1....................................... 14.8 (12, 18)
Class 3....................................... 19.7 (15, 24)
Class 4....................................... 27.0 (22, 49)
Class 1-4 (Filtering Facepieces).............. 18.1 (15, 22)
Class 5 (Elastomerics)........................ 12.0 (7, 14)
-------------------------
Total..................................... 14.7 (13, 18)
------------------------------------------------------------------------
5. Comparison of Respirators Approved Under 30 CFR Part 11 Versus 42
CFR Part 84
Several commenters expressed concern that the majority of WPF and
SWPF studies were conducted on respirators certified by NIOSH under
requirements in 30 CFR 11, instead of the newer NIOSH certification
procedure described in 42 CFR 84. While these commenters did not
explain the basis of their concern, two major studies were submitted
that examined the performance of 42 CFR 84-approved respirators. The 3M
study by Colton and Bidwell (Ex. 9-16-1-1) evaluated one respirator
approved under 30 CFR 11, and two respirators approved under 42 CFR 84.
In this study, WPFs were measured on up to nine different occasions for
21 workers (143 total measurements), 17 of whom used each type of
respirator on at least one occasion, with none of them using the same
type respirator on more than three occasions. Thus, this study provides
an opportunity for comparing the performance of respirators approved
under the two standards. Table III-5 shows the performance of these
three respirators using three methods: the proportion of samples with
Ci non-detects, the distribution of the 30 smallest WPF values among
the three respirators, and the geometric mean of WPFs. The two 42 CFR
84-approved respirators performed similarly with each of these methods,
and they both performed better than the 30 CFR 11-approved respirator
(see Table III-5).
Table III-5.--Performance of the 30 CFR Part 11 Respirator (3M 8710) and
the 42 CFR Part 84 Respirators (3M 8511 and 3M 8210)
------------------------------------------------------------------------
Inside-the- Dist. of 30 WPF
mask non- smallest geometric
detects WPF means \1\
------------------------------------------------------------------------
3M 8710.......................... 5/49 15 792
3M 8511.......................... 23/47 7 2506
3M 8210.......................... 19/47 8 2405
------------------------------------------------------------------------
\1\ Modeled assuming log-normal distribution with non-detects set at
detectin limit.
The geometric means of WPFs of the 42 CFR 84 respirators were
similar (2506 and 2405), and were significantly (p < 0.0001) higher
than the geometric mean of the 30 CFR 11 respirator (792). This
comparison was made using a repeated measures analysis that accounted
for dependence among different samples collected from the same worker,
assumed log-normally distributed WPFs, and set non-detects at the
detection limit (which should minimize differences between the two
respirator types). All three respirators performed well in this study,
with the smallest of the 143 WPFs being 52, well above the APF of 10
proposed by OSHA.
When the 146 WPF measurements from the Bidwell and Janssen study
(Ex. 9-16) (that assessed the 3M 9211 respirator approved under 42 CFR
84) are added to the 94 WPFs from the Colton and Bidwell study (Ex. 9-
16-1-1), 240 WPFs in the OSHA database are from 42 CFR 84 respirators.
None of these WPFs was less than 10 (0/240). This finding, along with
the evidence that 42 CFR 84 respirators performed better than 30 CFR 11
respirators in the same study, suggests that the new filtering
facepiece respirators certified under 42 CFR 84 may perform better than
the respirators relied on by OSHA for its analyses, which consisted
mainly of respirators approved under 30 CFR 11. Because the respirators
approved under 42 CFR 84 outperformed those respirators approved under
30 CFR 11, which were adequately protective, OSHA is confident current
workers will be well protected by the respirators approved under 42 CFR
84.
6. Methodology of Evaluating Overexposure
Another method to assess the appropriateness of an APF is to
determine whether an overexposure occurs (Ex. 10-17). The Agency
reviewed relevant studies on this subject cited by several commenters
(Exs. 9-16, 9-22, and 10-17-1) to determine if such an analysis would
provide useful information on filtering facepiece and elastomeric half
mask respirators.
Two major studies (Exs. 9-16-1-9 and 4-21) address the likelihood
that half mask respirators will not sufficiently reduce occupational
exposures to airborne contaminants. In the first of these two studies
(Nelson et al., Ex. 9-16-1-9), the authors evaluated the risk of
overexposure for selected APFs using Monte Carlo simulation modeling.
For a half mask respirator with an APF of 10, the calculations
indicated a low risk of being exposed above an occupational exposure
limit (OEL), with mean exposures being controlled well below an OEL. In
the second article by Drs. Myers and Zhuang (Ex. 4-21), ambient (Co)
and in-facepiece exposure monitoring data (Ci) from studies of worker
exposures in foundry, aircraft-painting, and steel-manufacturing
industries were compared with the OSHA PEL for single-substance
exposures. The 5th percentiles of the protection factor (Co/Ci) data
from each study were calculated. The authors used a new binomial
analysis of likelihood of successes (no overexposure) and failures
(overexposures). Their calculations indicate, for both half mask
elastomeric and filtering facepiece respirators, that the < 5% of
workers who fail to achieve an APF of 10 are still being protected.
OSHA considered Nelson's analysis along with the findings of Myers
and Zhuang when it conducted its own analysis. Accordingly, the Agency
was persuaded to quantify the probability of overexposure by applying
the Myers and Zhuang binomial analysis to OSHA's updated database.
OSHA's expert, Dr. Gerry Wood, performed the analysis and presented his
results in a report (Ex. 20-3) described below. The updated OSHA half
mask database (Ex. 20-2) used in this analysis contains 1,339 WPFs from
studies with both filtering facepiece half mask respirators (760 WPFs)
and elastomeric half mask respirators with cartridge filters (579
WPFs). This database also contains Co and Ci measurements (expressed in
[mu]g/m\3\), with asbestos fiber counts converted as follows: 1 fiber/
cm\3\ = 30 [mu]g/m\3\); these measurements permit binomial analysis of
overexposure through calculation of hazard ratios (HR).
The following 8-hour TWA PELs were used to calculate HR = Co/PEL
for this study (see Table III-6).
Table III-6.--8-Hour TWA PELs Used to Calculate the Hazard Ratios
------------------------------------------------------------------------
Analyte PEL (mg/m3)
------------------------------------------------------------------------
Benzo(a)pyrene............................ 0.2
Lead...................................... 0.05
Zinc...................................... 15
Iron...................................... 10
Chromium.................................. 0.5
Titanium.................................. 15
Manganese................................. 5
Aluminum.................................. 15
Asbestos.................................. 0.003 (0.1 fiber/cm3)
Silica.................................... 10
Cadmium................................... 0.005
Calcium................................... 15
------------------------------------------------------------------------
Values for individual WPFs then were plotted against HR as
illustrated in the figures of the Myers and Zhuang reference (Ex. 4-21,
Figure 1, page 798, and Figure 2, page 799). The same reference lines
and labels were used, but the scales were expanded to include all data
in the OSHA database.
Figure 1 below shows the plot of all data for both filtering
facepieces and elastomerics. The line labeled CD represents WPF = 10;
38 (2.8%) of the 1,339 data points fell below this line and five data
points (0.37%) fell within the triangle defined by the letters ABK;
Myers and Zhuang (Ex. 4-21) label this triangle as "Inadequate
Protection, Overexposure," which corresponds to the region in which Ci
exceeds the PEL.
Figure 2 shows the same plot for studies using filtering facepieces
only. Twelve data points (1.6%) are below the WPF = 10 line. Two of
these twelve data points equal WPF = 10 when rounded off to the nearest
whole number. Only 2 (0.26%) of the points are within the ABK
overexposure region. The data point in the A corner (from a study by
Colton (Ex. 1-64-16, CL4.15.Pb)) represents a Co just above the lead
PEL (HR = 1.20) that, with a WPF = 1.15 (almost no protection), gave a
Ci = 1.04 * PEL; this value represents an inside-the-mask exposure just
barely higher than the PEL. The only other data point in the over-
exposure region is from the asbestos (PEL-0.1 fiber/cm3)
study by Dixon (Ex. 1-64-54, CL1.2.Asb) which corresponds to HR = 77,
WPF = 47, and a Ci = 1.6 * PEL, (or 0.16 fiber/cm3).
If the MUC is defined as MUC = APF x PEL, and an APF = 10 is
assumed, then data points in the triangle labeled AHE represent
overexposures. With one data point in this triangle, filtering
facepieces are 99.4% effective in protecting employees at an APF = 10
and an MUC = 10 x PEL (i.e., 160 of 161 data points in the AGFE area,
with an HR ranging from 1 to 10, are outside the triangle (AHE) that
represents diminished protection).
Figure 3 shows the same plot for the elastomerics. Of these 579
data points, 26 (4.5%) fall below WPF = 10. Three data points (0.5%) in
the ABK overexposure triangle are from an asbestos study by Dixon (Ex.
1-64-54, CL5.2.Abs). However, no data points of 265 in the AGFE area
fall within the AHE triangle, indicating that all of these respirators
provided protection at APF = 10 x PEL.
Figures 4 and 5 demonstrate that both filtering facepiece and
elastomeric respirators maintain the level of employee protection found
in Figures 2 and 3, even when the data are plotted using the higher
PELs specified by the older OSHA asbestos standard (pre-August 1994)
and cadmium standard (pre-April 1993). The combined data for both
Figures 4 and 5 show that filtering facepieces had only one data point
of 160 (with an HR ratio of 1 to 10) in the overexposure area (i.e.,
the AHE triangle), while none of the 241 data points for elastomeric
respirators fell into this area. Therefore, Figures 4 and 5 and Figures
2 and 3 demonstrate that both filtering facepiece and elastomeric
respirators afford employees effective protection against two different
exposure levels of asbestos and cadmium.
BILLING CODE 4510-26-P
BILLING CODE 4510-26-C
7. Summary of Quantitative Analyses of the Updated Database
First, OSHA's database includes the best available data. As part of
the APF rulemaking process, the Agency conducted a metaanalysis of data
collected from numerous scientific studies related to APFs. OSHA
established criteria that were used to evaluate each study's design and
data quality to assure that the database included only the most valid
data. The Agency, at each step in the rulemaking process, called on
participants to identify additional studies to augment the dataset or
to discuss alternative methods of analysis. In response, a number of
commenters expressed these concerns about the data analysis: The
statistical treatment minimized the true differences between elastomeric
and filtering facepieces, and there was too much variability in the data.
In all cases, concerns raised by commenters about the composition of the
dataset used in the metaanalysis, or the statistical methods used to
conduct the analyses, were unsubstantiated by evidence submitted to the
record despite repeated requests by OSHA for either specific examples or
additional evidence.
Second, the best available data support an APF of 10 for half mask
elastomerics and filtering facepieces. The final APF half mask database
consists of 1,339 data points from 16 different studies, which
represents a data increase of 46% over the 917 data points initially
available for analysis in the proposal. The full data set indicates:
(a) The precise APF for filtering facepieces is 18.1, with a 90%
confidence interval between 15 and 22; (b) the precise APF for
elastomerics is 12.0, with a 90% confidence interval between 7 and 14;
and (c) that a greater percentage of elastomerics failed to achieve an
APF of 10 (4.5%) than filtering facepieces (1.6%). In both cases, fewer
than 5% of the respirators failed to achieve an APF of 10, which is the
maximum failure rate historically allowed by both OSHA and other
standards-setting bodies.
Third, OSHA substantiated its previous analysis by adding to its
updated database 403 data points that were excluded originally because
they did not meet OSHA's selection criteria and reanalyzing the
database. This additional analysis also supports an APF of 10 for both
types of respirators, with the results being highly similar to the
analysis based on the best-available data.
Fourth, new studies submitted during the rulemaking allowed OSHA to
compare the performance of similar respirators that were certified
under both NIOSH's old (30 CFR 11) and new (42 CFR 84) certification
standards. The 42 CFR 84 respirators achieved a WPF that was better
than the 30 CFR 11 respirators. This finding is significant because the
majority of the WPF studies, and the only studies in OSHA's original
data set, were conducted on respirators certified under 30 CFR 11.
Thus, the improved performance of 42 CFR 84 respirators indicates that
these respirators are likely to be even more protective of worker
health than an APF of 10 as provided for in the final rule.
OSHA also addressed the issue of overexposure among workers. In
doing so, it reviewed the respirator literature and performed an
analysis of overexposure risk using filtering facepiece or elastomeric
respirators. Based on this risk analysis, OSHA concluded that workers
participating in effective respirator programs had an extremely low
risk of overexposure.
In conclusion, the extensive quantitative analyses of the databases
clearly indicate that both filtering facepieces and elastomeric
respirators are capable of achieving an APF of 10. The results
demonstrate that no statistical justification exists for assigning an
APF of less than 10 to either of these two types of respirators.
Finally, the results show that an APF of 10 is an underestimate of the
true protection provided by both types of respirators. Therefore, the
final APF of 10 determined by this rulemaking provides employees who
use respirators with an extra margin of safety against airborne
contaminants.
F. Summary of Studies Submitted During the Rulemaking
1. Additional Studies Used in the Updated Analyses
OSHA found the studies discussed in this section to be of
sufficient quality for inclusion in its APF analyses.
Bidwell and Janssen study (Exs. 9-16-1-1 and 9-16). J. O. Bidwell
and L. Janssen of 3M gave a presentation at the May 2003 American
Industrial Hygiene Conference and Exposition (AIHCE) on a workplace
protection factor study they performed in a concrete-block
manufacturing plant with workers using a NIOSH-approved N95 flatfold
filtering facepiece respirator. The filtering facepiece respirator
tested was the 3M Particulate Respirator 9211, approved by NIOSH under
the 42 CFR 84 respirator certification standards. The authors measured
silicon and calcium exposures to 19 workers in the bagging and block-
handling areas of the plant. In the bagging area, workers placed bags
over cement-dust chutes for filling, and then transferred the bags to
pallets. In the other areas of the plant sampled by the authors,
workers handled concrete blocks, swept and shoveled dust and block
pieces into containers, and cleaned out mullers with chipping tools.
The workers were informed of the purpose and procedures of, and their
role in, the study, and were provided with instructions on proper
donning, fitting, and user seal check procedures, as well as respirator
operation. In addition, the workers had to pass a Bitrex[supreg]
qualitative fit test that followed the fit test protocol described in
OSHA's Respiratory Protection Standard prior to study participation.
They also had to be clean shaven. They were observed by the authors in
the workplace on a one-on-one basis throughout the sampling periods.
The inside-the-facepiece sampling train consisted of a 25-mm three-
piece cassette with a 0.8-micron pore-size polycarbonate filter with
porous plastic back-up pads for collecting the inside samples. For
sampling purposes, a Liu probe was inserted opposite the mouth near the
midline of the respirator. It projected one centimeter into the
facepiece. The sampling cassette was attached directly to the probe,
and a cassette heater was used to prevent condensation of moisture from
exhaled breath. Outside-the-facepiece samples used a 25-mm three-piece
cassette with a 0.8-micron pore-size mixed cellulose-ester filter. The
outside sample cassette also was connected to a Liu probe, and this
combination was attached in the worker's breathing zone. Inside samples
and outside samples were collected at a flow rate of two liters per
minute. Respirators were donned and doffed, and sampling trains started
and stopped, in a clean area. Field blanks were used to evaluate for
sample-handling contamination, and manufacturer blanks were collected
to determine background contamination on the filters.
The inside samples were analyzed using proton-induced X-ray
emission analysis (PIXEA), and the outside samples were analyzed by
inductively coupled plasma (ICP) spectroscopy. For both calcium and
silicon, the authors presented the range of Co, Ci, and the associated
geometric means and standard deviations. Three sets of WPF results were
determined: One for calcium, a second for silicon, and a harmonic mean
for the combined calcium and silicon samples. Silicon was not detected
on eleven of the Ci samples. However, by using 70% of the limit of
detection as the inside mass, the authors were able to include these
samples in the statistical analysis. No field-blank adjustments were
made (i.e., no calcium or silicon detected), and no mention is made of
adjusting the data for pulmonary retention of particles. In addition,
three sample sets were invalidated as a result of equipment and
procedural problems. The authors reported a mean WPF of 152, with a 5th
percentile of 13, for the calcium samples; a mean WPF of 394, with a
5th percentile of 34, for the silicon samples; and a harmonic mean of
the calcium and silicon samples of 206, with a 5th percentile of 20.
The authors noted a difference in the WPFs measured for calcium and
silicon (using the same respirator), and discussed a number of possible
reasons for the difference (e.g., random sampling and analytical
errors, possible non-uniformity of the challenge aerosol over time). The
authors concluded, "The estimated WPF for this respirator model based
on this study exceeds the APF of 10 assigned to this respirator class
by ANSI Z88.2-1992 and proposed by OSHA." They also stated, "The
respirator provided an adequate level of protection and reliably
provided workplace protection factors of at least 10 when properly
fitted, worn, and used" (Ex. 9-16, page 40).
Colton and Bidwell study (Ex. 4-10-4). C. Colton and J. Bidwell of
3M made a presentation on May 25, 1995 at the AIHCE comparing the
workplace performance of two different types of HEPA filters on an
elastomeric half mask respirator in a battery manufacturing plant. The
HEPA filters and the respirator model tested were approved under the 30
CFR 11 respirator certification standards. The half facepiece
respirator tested was the 3M 7000, available in three sizes. The HEPA
filters tested were the 3M 7255 high-efficiency (mechanical) filter and
the 3M 2040 high efficiency (electret) filter. The authors measured
lead exposures for 19 workers in the battery-pasting and assembly areas
of the plant because these areas had the highest lead exposures. The
workers were informed of the purpose and procedures of, and their role
in, the study, and were provided with instructions on proper donning
and fitting procedures, as well as respirator operation. In addition,
the workers had to pass a saccharin qualitative fit test performed
using the fit test protocol described in OSHA's Lead Standard. Workers
had to be clean shaven. They were observed in the workplace by the
authors on a one-on-one basis throughout the sampling periods.
For sampling purposes, a Liu probe was inserted opposite the mouth
near the midline of the respirator. It projected one centimeter into
the facepiece. The sampling cassette was attached directly to the
probe, and a cassette heater was used to prevent condensation of
moisture from exhaled breath. A Liu probe was also attached to the
outside sample to ensure that particle loss for the outside samples
would be similar to that with the inside samples. Inside samples and
outside samples were collected at a flow rate of two liters per minute,
and sampling times ranged from 56 to 200 minutes. Up to four samples
were collected per day on each worker, each worker was sampled for two
days, field blanks were used, and care was taken to avoid handling
contamination. The filter for the first day was assigned randomly, with
a worker using one filter type on the first day and the second filter
type on the second day.
The inside- and outside-the-facepiece samples were analyzed for
lead by ICP spectroscopy. The authors presented the range of outside
and inside lead concentrations, and the associated geometric means and
standard deviations. Two sets of WPF results were determined: One for
the 3M 2040 filter and a second for the 3M 7255. A total of 140 samples
were collected--one sample was eliminated due to low mass loading, 10
samples were lost due to equipment problems, and 85 samples had inside-
sample mass values that were non-detectable. Of the remaining 44
samples, one outlier was identified in the electret filter data set,
leaving 22 sets for the 3M 2040 filter and 21 sets for the 3M 7255
filter. No field blank adjustments were reported (i.e., no lead was
detected on the field blanks). The authors reported a mean WPF of 562
and a 5th percentile of 71 for the 3M 2040 filter-respirator
combination, and a mean WPF of 1006 and a 5th percentile of 80 for the
3M 7255 filter-respirator combination.
When no lead was detected for the inside samples, the WPF results
were recalculated using the detection limit to represent the mass for
these samples. From these recalculations, the authors identified one
outlier in the electret filter data set and two outliers in the
mechanical filter data set. They then calculated geometric means,
geometric standard deviations, and 5th percentile WPFs for the 67
samples for the 3M 2040 filter and for the 59 samples for the 3M 7255
filter. The authors reported a mean WPF of 420 and a 5th percentile of
101 for the 3M 2040 filter-respirator combination, and a mean WPF of
549 and a 5th percentile of 138 for the 3M 7255 filter-respirator
combination.
The authors concluded that the performance differences between the
two filter types were not statistically significant. Both filters
provided 5th percentile protection factors above 10. No WPFs were less
than 30. Under these workplace conditions, no difference was found in
the level of protection provided by the electrostatic HEPA filter
compared to a mechanical HEPA filter.
Colton and Bidwell study (Ex. 9-16). C. Colton and J. Bidwell of 3M
presented a research paper at the May 1999 AIHCE on a WPF study they
performed in a battery manufacturing plant with workers using three
NIOSH-approved filtering facepiece respirators. The filtering facepiece
respirators tested were the 3M 8210 and 3M 8511, approved by NIOSH
under the 42 CFR 84 respirator certification standards, and the 3M 8710
filtering facepiece, approved by NIOSH under the 30 CFR 11 respirator
certification standards. The authors measured lead exposures for 21
workers in the battery-manufacturing and assembly areas of the plant.
The worker job classifications tested were stackers, heat sealers,
burners, and assemblers. The workers were informed of the purpose and
procedures of, and their role in, the study, and were provided with
instructions on proper donning, fitting, and user seal check
procedures, as well as respirator operation. In addition, the workers
had to pass a Bitrex[supreg] qualitative fit test with all three
respirators, and they had to be clean shaven. They were observed in the
workplace by the authors on a one-on-one basis throughout the sampling
periods.
The sampling probe was a Liu probe that was inserted opposite the
mouth near the midline of the respirator. It projected one centimeter
into the facepiece. The sampling cassette was attached directly to the
probe, and a cassette heater was used to prevent condensation of
moisture from exhaled breath. Inside and outside samples were collected
at a flow rate of two liters per minute for 79 to 159 minutes. Three
samples were collected per day for each worker. Field blanks were used,
and care was taken to avoid handling contamination.
The inside samples were analyzed for lead using PIXEA. Outside
samples were analyzed by ICP spectroscopy. The authors presented the
range of outside and inside sample lead concentrations, and the
associated geometric means and standard deviations for each respirator
model tested. Three sets of WPF results were determined: One for the 3M
8710, a second for the 3M 8210, and a third for the 3M 8511. Lead was
not detected on five of the inside samples for the 3M 8710, 19 for the
3M 8210, and 23 for the 3M 8511. No field blank adjustments were
reported (i.e., no lead was detected on the field blanks). The authors
reported a mean WPF of 730, with a 5th percentile of 105, for the 3M
8710 respirator; a mean WPF of 955, with a 5th percentile of 73, for
the 3M 8210; and a mean WPF of 673, with a 5th percentile WPF of 169,
for the 3M 8511 using test samples with detectable lead levels. When no
lead was detected on the inside samples, the WPF results were
calculated by using 70% of the limit of detection as the mass for
inside samples. The authors reported a mean WPF of 804, with a 5th
percentile of 111, for the 3M 8710 respirator; a mean WPF of 2210, with
a 5th percentile of 133, for the 3M 8210; and a mean WPF of 1970, with a
5th percentile WPF of 223, for the 3M 8511.
The authors stated, "All respirator models provided an equivalent
level of protection," and that "[a]ll the respirators tested reliably
provided workplace protection factors of 10 when properly fitted, worn,
and used." No reported WPFs were less than 51, and no difference in
workplace protection was found between workers using 30 CFR part 11-
approved respirators and workers using 42 CFR 84-approved respirators.
The authors concluded that, using the 5th percentile WPFs as an
indicator of performance, the APFs should not differ between these
respirators.
2. Additional Studies Not Used in the Updated Analyses
The Agency received a number of comments on the relationship
between fit testing and APFs. OSHA regulations require that when a
respirator user cannot pass a fit test with a particular respirator
model, it cannot be used. OSHA does not believe that it is appropriate
to assign a lower protection factor to a respirator (e.g., half the
APF) when the respirator doesn't fit. However, a number of fit test
studies, and one study on farm worker exposures to bioaerosols, were
submitted to the record for the Agency to evaluate in terms of APFs.
OSHA has evaluated these studies and determined that they do not meet
the criteria that data must meet to be included in the database. These
criteria have been described above.
NIOSH agreed (Tr. at 102) that the APF values resulting from OSHA's
multifaceted approach provide reasonable values for the level of
protection expected for each respirator class. Proposed Table 1
("Assigned Protection Factors") represents the state of the art for
each class or respirator. However, NIOSH stated that designating a
specific APF for a respirator class will not ensure that a respirator
will perform as expected. The protection afforded by a respirator is
contingent on: The respirator user adhering to the respirator program
requirements of OSHA's Respiratory Protection Standard; the use of
NIOSH-certified respirators in their approved configuration; and fit
testing for each employee that ensures selection of a properly fitting
respirator. The following studies, which OSHA did not include in its
updated analyses, typically violated one or more of these three
conditions.
Don-Hee Han study (Ex. 9-13-2). NIOSH (Ex. 9-13) submitted a study
by Don-Hee Han (Ex. 9-13-2) of the 3M 8511 cup-shaped filtering
facepiece, the MSA Affinity foldable FR 200, and the Willson N95 10FL
produced by Dalloz Safety in response to OSHA's request in the NPRM for
additional studies that may be useful in determining APFs. The author
of the study permitted workers who did not pass a fit test with a
minimum fit factor of 100, as required by OSHA's Respiratory Protection
Standard, to participate in the study. OSHA reviewed this study and did
not add the data set to its quantitative analyses because it was a PPF
study that is not directly comparable with WFP studies used by OSHA in
its APF determinations. However, the study results confirmed that when
a worker's filtering facepiece respirator is fit tested properly, it is
capable of achieving a protection factor of at least 10.
Peacock study (Ex. 9-13-4). This fit test research report was
submitted to the record by NIOSH. In this study, a liquid-aerosol QNFT
(Large Particle QNFT (LPQNFT)) was developed and used to evaluate
filter penetration of a regular N95 respirator. Protection factors
determined by the LPQNFT were compared to fit factors obtained using
the saccharin QLFT. The sensitivity and specificity of the saccharin
QLFT were evaluated. The results for the specifity of the LPQNFT
indicated that workers who failed the saccharin QLFT also failed the
LPQNFT when using a protection factor >= 100. The sensitivity was low.
Twelve (12) subjects passed both the LPQNFT and the saccharin QLFT (out
of 28 subjects), but another 16 subjects failed the saccharin test
while passing the LPQNFT. Peacock concluded that the LPQNFT may be
subject to particle deposition at leakage sites, as well as conditions
inside the facepiece that would lead to sampling bias. OSHA did not
rely on these fit test data for setting APFs because, as Peacock noted,
further studies should be conducted to identify the cause of these
problems.
Lee and Nicas study (Ex. 17-7-3). NIOSH submitted this study of N95
respirators used against Mycobacterium tuberculosis (TB). In this
study, Lee and Nicas (Ex. 17-7-3) computed risks of TB infection using
five medium- or regular-size N95 filtering facepiece respirators. Five
NIOSH-approved respirators were selected for evaluation after reviewing
manufacturer-provided fit test, comfort, and cost data. After extensive
evaluation, the original five brands were rank ordered from highest to
lowest fit test pass rates, and the authors calculated the risk of TB
transmission. The authors concluded that fit testing is necessary to
ensure that respirators perform as expected. However, OSHA did not
accept this study for its APF analyses because it is not a WPF or SWPF
study, and addresses only fit testing issues.
Coffey, et al. study (Ex. 17-7-4). NIOSH submitted to the record a
publication by Coffey et al. (Ex. 17-7-4). In this study, 18 N95
filtering facepiece respirators were evaluated. The authors determined
the following measurements from the results: 5th percentile SWPF value;
the average SWPF per shift; the h-value; and the assignment error. A
SWPF test was used to determine respirator performance, which was
assessed using a Portacount Plus with test subjects performing six
standard fit test exercises. However, the generally accepted format for
a SWPF study involves test subjects performing simulated workplace
exercises (e.g., shoveling pebbles, moving blocks, pounding nails).
Using this procedure, the authors found that when properly fit
tested, over 80% of the poorly performing respirators achieved a
protection factor of more than 10. However, OSHA did not use this study
in its APF determinations since this was not a WPF or SWPF study.
Nevertheless, the study supports the requirement that APFs apply only
when used within the context of a comprehensive respirator program.
Reponen et al. study (Exs. 19-8-3 and 19-8-4). The purpose of this
study was to further develop a prototype personal-sampling system for
use with N95 filtering facepiece respirators. The study results were
calculated from 30-60 minute Co and Ci measurements taken across
multiple agricultural settings, tasks, and simulated exposures. The
data were combined to calculate dust, microorganism, and cultured
microorganism exposures. Descriptions of tasks in several workplaces
were provided.
The N95 respirators in this study performed at or above a WPF of 10
when evaluated using dust measurements. However, the dust-exposure
measurements counted both dust particles and microorganisms because the
optical-particle counter used for this purpose does not differentiate
between organic and nonorganic particles. When they calculated WPFs for
the microorganism samples alone, the WPFs decreased somewhat. The
authors concluded that the geometric mean WPF increased with increasing
particle size, and that the WPFs were smaller for biological particles
than for dust. The authors speculated that differences in WPFs may
result from the measurement effects of particle size or density. They
also said that even a small variation in the density of particles can
have a pronounced effect on the loss of dust particles through faceseal
leaks due to impaction. The authors concluded that their findings deserve
further research.
OSHA agrees with the authors that further research is needed to
substantiate and explore these findings. Also, the Agency has
significant concern regarding the measurement methodology used in this
prototype study. For example, it is not clear whether the WPF
differences are valid or are simply the result of using different
measurement methods. Therefore, the Agency decided not to use this
study for developing APFs.
Summary and conclusions for studies not used in the updated
database. OSHA reviewed the studies submitted to the APF rulemaking
docket and determined that five of them were unsuitable for the
database used to develop APFs. OSHA established a set of criteria in
the proposal for evaluating new studies for inclusion in the APF
database. The studies by Han (Ex. 9-13-4), Peacock (Ex. 9-13-4), Lee
and Nicas (Ex. 17-7-3), Coffey et al. (Ex 17-7-4), and Reponen et al.
(Exs. 19-8-3 and 19-8-4) were not used by OSHA in setting the final
APFs because these studies did not follow established WPF or SWPF
protocols, or required further research to substantiate or explore the
results.
IV. Health Effects
American workers use respirators as a means of protection against a
multitude of respiratory hazards that include chemical, biological, and
radiological agents. Respirators provide protection from hazards that
are immediately life-threatening, as well as hazards associated with
routine operations for which engineering controls and work practices do
not protect employees sufficiently. When respirators fail, or do not
provide the degree of protection expected by the user, the user is
placed at an increased risk of adverse health effects that result from
exposure to the respiratory hazards present. Therefore, it is critical
that respirators perform properly to ensure that users are not at an
increased risk of experiencing adverse effects caused by exposure to
respiratory hazards.
In this final rulemaking, OSHA defined the minimal level of
protection a respirator is expected to achieve (i.e., the APFs in Table
1), as well as the MUCs for the respirators. The Agency also is
superseding most of the existing APF table requirements in its
substance-specific standards. By superceding the APF tables, the Agency
estimates that the benefits for the final APFs under the Respiratory
Protection Standard will be available as well to employers who must
select respirators for employee use under the substance-specific
standards. In addition, the Agency believes that harmonizing the APFs
of the substance-specific standards with the APFs in the Respiratory
Protection Standard will reduce confusion among the regulated community
and aids in uniform application of APFs, while maintaining employee
protection at levels at least as protective as the existing APF
requirements.
V. Summary of the Final Economic Analysis and Regulatory Flexibility
Analysis
A. Introduction
OSHA's Final Economic and Regulatory Flexibility Screening Analysis
(FEA) addresses issues related to the costs, benefits, technological
and economic feasibility, and economic impacts (including small
business impacts) of the Agency's Assigned Protection Factors (APF)
rule. The Agency has determined that this rule is not an economically
significant rule under Executive Order 12866. The economic analysis
meets the requirements of both Executive Order 12866 and the Regulatory
Flexibility Act (RFA; as amended in 1996). The FEA presents OSHA's full
economic analysis and methodology. The Agency entered the complete FEA
into the docket as Exhibit 11. The remainder of this section summarizes
the results of that analysis.
The purpose of this FEA is to:
Evaluate the costs employers would incur to meet the
requirements of the APF rule;
Estimate the benefits of the rule;
Assess the economic feasibility of the rule for affected
industries; and
Determine the impacts of the rule on small entities and
the need for a Regulatory Flexibility Analysis.
B. The Rule and Affected Respirator Users
OSHA's APF rule would amend 29 CFR 1910.134(d)(3)(i)(A) of the
Respiratory Protection Standard by specifying a set of APFs for each
class of respirators. These APFs specify the highest multiple of a
contaminant's permissible exposure limit (PEL) at which an employee can
use a respirator safely. The APFs would apply to respirator use for
protection against overexposure to any substance regulated under 29 CFR
1910.1000. In addition, OSHA rules for specific substances under
subpart Z (regulated under the authority of section 6(b)(5) of the OSH
Act of 1970, 29 U.S.C. 655) specify APFs for respirators used for
protection against these chemicals (hereafter referred to as Sec.
6(b)(5) substances). The rule would supercede most of these protection
factors, and harmonize APFs for these substances with those for general
respirator use.
OSHA based estimates of the number of employees using respirators
and the corresponding number of respirator-using establishments on the
NIOSH-BLS survey of respirator use and practices \2\ (Ex. 6-3). The
NIOSH-BLS survey provides up-to-date use estimates by two-digit
industry sector and respirator type for establishments in which
employees used respirators during the previous 12 months.\3\ As shown
in Table V-1, an estimated 291,085 establishments reported respirator
use in industries covered by OSHA's regulation. Most of these
establishments (208,528 or 71.6 percent) reported use of filtering
facepieces. Substantial percentages of establishments also reported the
use of half-mask and full facepiece non-powered air-purifying
respirators (49.0 and 21.4 percent, respectively). A smaller number of
establishments reported use of powered air-purifying respirators
(PAPRs) and supplied-air respirators (SARs). Fifteen percent of
establishments with respirators (43,154) reported using PAPRs and 19
percent (56,022) reported using SARs. Table V-2 presents estimates of
the number of respirator users by two-digit industry sector. An
estimated 2.3 million employees used filtering facepiece respirators in
the last 12 months, while 1.5 million used half masks, and 0.7 million
used full facepiece non-powered air-purifying respirators. Fewer
employees reported using PAPRs (0.3 million) and SARs (0.4 million).
The industry-specific estimates show substantial respirator use in
several industries, including the construction sector, several
manufacturing industries (SICs 28, 33, 34, and 37), and Health services
(SIC 80).
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\2\ Preliminary results from the 2001 NIOSH-BLS "Survey of
Respirator Use and Practices" in press. NIOSH commissioned the
survey to be conducted by BLS, who also tabulated the data after
completing the survey.
\3\ The survey was conducted between August 2001 and January
2002. It asked: "During the past 12 months, how many of your
current employees used respirators at your establishment?" It
excluded voluntary use of respirators from detailed followup
respirator use questions (Ex. 6-3).
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The standard would have different impacts on employers using
respirators to comply with OSHA substance-specific standards than for
employers using respirators for other purposes. Therefore, OSHA used
findings from the NIOSH-BLS survey of establishments that reported
respirator use, by general respirator class, for protection against
specific substances (see Table V-3). OSHA applied these numbers to all
respirator users and establishments within the industries that make up
each sector to derive substance-specific estimates of respirator use.
For those Sec. 6(b)(5) substances not reported by NIOSH, OSHA used
expert judgments of a consultant with experience in the respirator
industry to estimate the percentage of establishments and employees
that use respirators for protection against these chemicals (Ex. 6-2)
(see Table V-3).
C. Compliance Costs
The standard does not raise issues of technological feasibility
because it requires only that employers use respirators already on the
market. Further, these respirators are already in use and have proven
feasible in a wide variety of industrial settings. However, costs for
the APF standard result from requiring some users to switch to more
protective respirators than they currently use. When the APF is lower
than the baseline (current) APF, respirator users must upgrade to a
more protective model. Both the 1992 ANSI Z88.2 Respiratory Protection
Standard and the 1987 NIOSH RDL specify APFs for certain classes of
respirators. The Agency assumed that employers currently use the ANSI
or NIOSH APFs, or the APFs in the OSHA substance-specific standards, as
applicable, to select respirators. While the Agency currently refers to
the NIOSH RDL as its primary reference for APFs, in the absence of an
applicable OSHA standard, this analysis assumes that, in most cases,
adhering to the existing ANSI APFs fulfills employers' legal obligation
for proper respirator selection under the existing Respiratory
Protection Standard. However, in the case of full facepiece negative
pressure respirators, the Agency has established that an APF of 50, as
opposed to ANSI's APF of 100, is currently acceptable. In this regard,
all but one of the substance-specific standards with APFs for full
facepiece negative pressure respirators set an APF of 50. In addition,
the existing respirator rule and its supporting preamble require that
quantitative fit testing of full facepiece negative pressure
respirators must achieve a fit factor of 500 when employees use them in
atmospheres in excess of 10 times the PEL; this requirement assumes a
safety factor of 10. Therefore, based on a fit factor of 500, such
respirators are safe to wear in atmospheres up to 50 times the PEL,
consistent with similar requirements regarding respirator use found in
existing standards for Sec. 6(b)(5) chemicals.
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For each respirator type, OSHA compared the new and existing
standards and, where these new APFs were lower, identified an
incrementally more protective respirator model. To be adequate, the
more protective respirator must have an APF greater than the current
APF.
1. Number of Users Required To Upgrade Respirator Models
For a given respirator type, the number of users required to shift
to a more protective respirator depends on two factors: the total
number of users of that type, and the percentage of those users for
whom the ambient exposure level is greater than the APF. While survey
data are available to estimate the number of users, virtually no
information is available in the literature that provides a basis for
estimating the percentage of users required to upgrade respirators. The
percentage of workers switching respirators would depend on the profile
or frequency distribution of users' exposure to contaminants relative
to the PEL. For example, the Agency is lowering the APFs for full
facepiece respirators used to protect against cotton dust from 100 to
50; accordingly, when workers have ambient exposures that are greater
than 50 times the PEL, employers must upgrade the respirator from a
full facepiece negative pressure respirator to a more protective
respirator (e.g., a PAPR).
Because of the absence of data on this issue, OSHA made several
assumptions regarding the requirement to upgrade respirators. First,
OSHA assumed that employers use respirators only when their employees
have exposures above the PEL. Second, OSHA assumed employers use the
most inexpensive respirator permitted, taking into consideration the
employees' safety and compliance with regulatory requirements. These
assumptions most likely overestimate the cost of compliance because
many employers require their employees to use respirators when OSHA
does not require such use, or they require respirators with higher APFs
than OSHA currently requires. As a result, this analysis assumes shifts
in respirators that employers may have implemented already. Two
commenters on this issue agreed that these assumptions overestimate the
number of employers that would need to change respirators as a result
of this rule (see Exs. 9-16 and 13-8). One commenter (Ex. 9-16) noted
that "For about twenty years, 3M has looked for worksites where
employers were using respirators at concentrations at the upper end of
the APF range. We have not been able to find these worksites." This
commenter went on to note, as a result "we believe that the overall
compliance costs associated with the proposal, as currently written,
will likely be even lower than OSHA has estimated."
The Agency estimated distributions of exposures above the PELs
based on reports from its Integrated Management Information System
describing workplace monitoring of Sec. 6(b)(5) toxic substances
performed during OSHA health inspections. Of the 9,095 samples reported
above the PELs, 68.0 percent reported exposures between one and five
times the PEL, 13.1 percent found exposures between five and 10 times
the PEL, and 9.5 percent documented exposures between 10 and 25 times
the PEL. Exposures for the remaining 9.4 percent of the samples were
greater than 25 times the PEL. Based on these data, OSHA modeled the
current exposure distribution for each respirator type.
2. Incremental Costs of Upgrading Respirator Models
OSHA also analyzed the costs of upgrading from the current
respirator to a more protective alternative. In doing so, OSHA
estimated the annualized unit costs for each respirator type, including
equipment and accessory costs, and the costs for training and fit
testing. One commenter (Ex. 17-9) noted the importance of not just
considering the initial costs of a respirator, but all associated
costs. OSHA has considered all of these costs, including training, fit
testing, program development, and medical evaluation, as this commenter
suggested. OSHA then calculated the incremental cost for each combination
of upgrades from an existing model to a more protective one, taking into
account the effect of replacement before the end of the respirator's useful
life. These annualized costs range from $49.98 (for upgrading from a
supplied-air, demand mode, full facepiece respirator to a supplied-air,
continuous flow, half-mask respirator) to $963.73 (for upgrading from a
non-powered, air-purifying full facepiece respirator to a full
facepiece PAPR).
In certain instances, workers who use respirators under the
substance-specific standards may have to upgrade to a SAR with an
auxiliary escape SCBA. Several substance-specific standards currently
specify SARs for exposures that exceed 1,000 times the PEL.\4\ OSHA
believes that workers are unlikely to regularly use respirators at such
extreme exposure levels, i.e., they are most likely to use them only in
exceptional, possibly emergency-related situations. Furthermore,
exposures at levels more than 1,000 times the PEL would generally be at
or above levels deemed immediately dangerous to life or health (IDLH),
so employers already are required by the Respiratory Protection
Standard to provide each worker with a respirator that has SCBA
capability. For these reasons, this PERFSA estimated no impacts for
these situations.\5\
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\4\ These standards regulate cotton dust, coke oven emissions,
acrylonitrile, arsenic, DBCP, ethylene oxide, and lead.
\5\ Paragraph (d)(2) of the Respiratory Protection Standard
requires employers to provide either a pressure demand SCBA or a
pressure demand SAR with auxiliary SCBA to any employee who works in
IDLH atmospheres.
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3. Aggregate Compliance Costs
For each respirator type affected by the regulation, OSHA combined
the incremental costs of upgrading to a more protective respirator, the
estimated share of users forecast to upgrade, and the number of users
involved to estimate the compliance costs associated with each
respirator type. Table V-4 shows estimated compliance costs for OSHA's
APF rule. The rule would require 1,918 users of non-powered air-
purifying respirators to upgrade to some respirator more expensive than
they are now using at a cost of $1.8 million. The Agency estimates that
22,848 PAPR users would upgrade their respirators at a cost of $2.3
million. A relatively small number of SAR users (5,110) would upgrade
to more expensive respirators at a cost of $0.4 million. Industry-
specific compliance costs vary according to the number of respirator
users and the proportion of these users affected by the rule.
Industries with relatively large compliance costs include SIC 17,
Special trade contractors ($0.8 million), and SIC 80, Health services
($0.8 million).
As discussed previously, the Agency believes the actual costs of
the standard almost certainly are overestimated. The cost analysis
assumes all respirator wearers have levels of exposures that require
the particular respirator they are using. Under this assumption, 15,000
employees would be allowed to safely shift to a less expensive
respirator, which could lead to cost savings for the employer. Such
potential cost savings are not accounted for in this cost analysis.
In many cases, employers use respirators when respirators are not
required by OSHA, or use respirators more protective than required by
OSHA. As a result, OSHA's cost analysis overestimates the number of
employees who are affected by the standard, and therefore overestimates
costs associated with the standard.
D. Benefits
The benefits that would accrue to respirator users and their
employers take several forms. The standard would benefit workers by
reducing their exposures to respiratory hazards. Improved respirator
selection would augment previous improvements to the Respiratory
Protection Standard, such as better fit-test procedures and improved
training, contributing substantially to greater worker protection.
Estimates of benefits are difficult to calculate because of
uncertainties regarding the existing state of employer respirator-
selection practices and the number of covered work-related illnesses.
At the time of the 1998 revisions to the Respiratory Protection
Standard, the Agency estimated that the standard would avert between
843 and 9,282 work-related injuries and illnesses annually, with a best
estimate (expected value) of 4,046 averted illnesses and injuries
annually (63 FR 1173). In addition, OSHA estimated that the standard
would prevent between 351 and 1,626 deaths annually from cancer and
many other chronic diseases, including cardiovascular disease, with a
best estimate (expected value) of 932 averted deaths from these causes.
The APFs in this rulemaking will help ensure that these benefits are
achieved, as well as provide an additional degree of protection. These
APFs also will reduce employee exposures to several Sec. 6(b)(5)
chemicals covered by standards with outdated APF criteria, thereby
reducing exposures to chemicals such as asbestos, lead, cotton dust,
and arsenic.\6\ While the Agency did not quantify these benefits, it
estimates that 29,655 employees would have a higher degree of
respiratory protection under this APF standard. Of these employees, an
estimated 8,384 have exposure to lead, 7,287 to asbestos, and 3,747 to
cotton dust, all substances with substantial health risks.
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\6\ In the 1998 rulemaking revising the Respiratory Protection
Standard, the Final Economic Analysis noted that the standard would
not directly affect the benefits for the estimated 5% of employees
who use respirators under OSHA's substance-specific health standards
(except to the extent that uniformity of provisions improve
compliance). Therefore, the Agency likely over-estimated the
benefits of that rulemaking since the standard did not affect
directly the type of respirator used by those employees (63 FR
1173). Conversely, this rule directly addresses the APF provisions
of the substance-specific standards; therefore, this rule would
affect directly the respirators used by employees covered by these
standards.
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In addition to health benefits, OSHA believes other benefits result
from the harmonization of APF specifications, thereby making compliance
with the respirator rule easier for employers. Employers also benefit
from greater administrative ease in proper respirator selection.
Employers would no longer have to consult several sources and several
OSHA standards to determine the best choice of respirator, but could
make their choices based on a single, easily found regulation. Some
employers who now hire consultants to aid in choosing the proper
respirator should be able to make this choice on their own with the aid
of this rule. In addition to having only one set of numbers (i.e.,
APFs) to assist them with respirator selection for nearly all
substances, some employers may be able to streamline their respirator
stock by using one respirator class to meet their respirator needs
instead of several respirator classes. The increased ease of compliance
would also yield additional health benefits to employees using
respirators.
Alternatively, these APFs would clarify when employers can safely
place employees in respirators that impose less stress on the
cardiovascular system (e.g., filtering facepiece respirators). Many of
these alternative respirators may have the additional benefit of being
less expensive to purchase and operate. As previously discussed, OSHA
estimates that over 15,000 employees currently use respirators that
fall in this group (i.e., shift to a less expensive respirator).
One commenter (Ex. 9-16) agreed that the standard would have
significant benefits, saying:
3M concurs with OSHA's conclusion that significant health
benefits will accrue to workers as a result of this rulemaking. 3M
believes that the majority of these benefits will be the result of
simplification of the respirator selection process for employers.
This will in turn lead to greater compliance with OSHA's various
standards regarding exposure to toxic and harmful substances. * * *
In addition to these benefits from increased compliance, 3M also
concurs with OSHA's determination that the simplification and
clarification of the APF tables will result in lessening of
cardiovascular stress, as well as other potential stresses, because
of the ability to select a filtering facepiece respirator.
E. Economic Feasibility
OSHA is required to set standards that are feasible. To demonstrate
that a standard is feasible, the courts have held that OSHA must
"construct a reasonable estimate of compliance costs and demonstrate a
reasonable likelihood that these costs will not threaten the existence
or competitive structure of an industry" (United Steelworkers of
America, AFL-CIO-CLC v. Marshall (the "Lead" decision), 647 F.2d 1189
(DC Cir. 1980)).
OSHA conducted its analysis of economic feasibility on an
establishment basis. Accordingly, for each affected industry, the
Agency compared estimates of per-establishment annualized compliance
costs with per-establishment estimates of revenues and per-
establishment estimates of profits. It used two worst-case assumptions
regarding the ability of employers to pass the costs of compliance
through to their customers: The no-cost-pass-through assumption, and
the full-cost-pass-through assumption. Based on the results of these
comparisons, which define the universe of potential impacts of the
APFs, OSHA then assessed the economic feasibility for all affected
establishments, i.e., those covered by this rule.
The Agency assumed that establishments falling within the scope of
the standard would have the same average sales and profits as other
establishments in their industries. OSHA believes this assumption is
reasonable because no evidence is available showing that the financial
characteristics of those firms with employees who use respirators are
different from firms that do not use respirators. In the absence of
such evidence, OSHA relied on the best available financial data (those
from the Bureau of the Census (Ex. 6-4) and Robert Morris Associates
(Ex. 6-5)), used a commonly accepted methodology to calculate industry
averages, and based its analysis of the significance of the projected
economic impacts and the feasibility of compliance on these data.
The analysis of the potential impacts of this standard on before-
tax profits and sales shown in Table V-5 is a "screening analysis,"
so called because it simply measures costs as a percentage of pre-tax
profits and sales under the worst-case assumptions discussed above, but
does not predict impacts on these before-tax profits or sales. OSHA
used the screening analysis to determine whether the compliance costs
potentially associated with the standard could lead to significant
impacts on all affected establishments. The actual impact of the
standard on the profit and sales of establishments in a specific
industry would depend on the price elasticity of demand for the
products or services of these establishments.
Table V-5 shows the economic impacts of these costs. For each
industry, OSHA constructed the average compliance cost per affected
establishment and compared it to average revenues and average
profits.\7\ These costs are quite small, i.e., less than 0.005 percent
of revenues; the one major exception is SIC 44 (Water transportation),
for which OSHA estimated the costs impacts to be 0.16 percent of
revenues. When the Agency compared average compliance costs with
profits, the costs also are small, i.e., less than 0.17 percent; again,
the major exception was SIC 44, which had an estimated impact of 2.12
percent of profits.\8\ Based on the very small impacts for
establishments in all industries shown in Table V-5, OSHA concludes
that the APF standard is economically feasible, in the sense of being
unlikely to close or alter the competitive structure of the affected
industries, for the affected establishments.
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\7\ OSHA defines "affected establishment" as any facility that
uses respirators, as represented in the NIOSH-BLS survey data.
\8\ For some industries, such as SIC 44, data from the NIOSH-BLS
survey were suppressed due to low response rates. In these cases,
the Agency, for the purposes of assessing economic feasibility,
imputed broader sector-level data from the survey to form an
estimate of respirator use. This procedure may result in
overestimating the impact of the standard (proposal) in some
industries. See the full FEA (Ex. 11) for further details.
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F. Economic Impacts to Small Entities
OSHA also estimated the economic impacts of the rule on affected
entities with fewer than 20 employees, and for affected small entities
as defined by the Small Business Administration (SBA). Table V-6 shows
the estimated economic impacts for small entities with fewer than 20
employees: average compliance costs by industry are less than 0.005
percent of average revenues, and less than 0.19 percent of profits, in
all industries. Table V-7 presents the economic impacts for small
entities as a whole, as defined by SBA. For these firms, average
compliance costs are less than 0.005 percent of average revenues and
less than 0.03 percent of average profits. Thus, the Agency projects no
significant impacts from the rule on small entities.
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When costs exceed one percent of revenues or five percent of
profits, OSHA considers the impact on small entities significant for
the purposes of complying with the RFA. For all classes of affected
small entities, the Agency found that the costs were less than one
percent of revenues and five percent of profits. Therefore, OSHA
certifies that this regulation would not have a significant impact on a
substantial number of small entities.
VI. Summary and Explanation of the Final Standard
This section of the preamble provides a summary and explanation of
each revision made to OSHA's Respiratory Protection Standard involving
APFs.
A. Definition of Assigned Protection Factor
As part of its 1994 proposed rulemaking for the Respiratory
Protection Standard, OSHA proposed a definition for APFs that read as
follows: "[T]he number assigned by NIOSH [the National Institute for
Occupational Safety and Health] to indicate the capability of a
respirator to afford a certain degree of protection in terms of fit and
filter/cartridge penetration" (59 FR 58938). OSHA proposed this
definition on the assumption that NIOSH would develop APFs for the
various respirator classes, building on the APFs in the 1987 NIOSH RDL
(59 FR 58901-58903). However, NIOSH subsequently decided not to publish
a list of APFs as part of its 42 CFR 84 Respirator Certification
Standards (60 FR 30338), and reserved APFs for a future NIOSH
rulemaking.
During his opening statement on June 15, 1995, at an OSHA-sponsored
expert-panel discussion on APFs, Adam Finkel, then Director of the
Agency's Directorate of Health Standards Programs, noted that OSHA
would explore developing its own list of APFs (H-049, Ex. 707-X). The
Agency then announced in the preamble to the final Respiratory
Protection Standard (63 FR 1182) that it would propose an APF table
"based on a thorough review and analysis of all relevant evidence" in
a subsequent rulemaking. In the final Respiratory Protection Standard,
OSHA reserved space for a table for APFs, a paragraph ((d)(3)(i)(A))
for APF requirements, and a definition of APF under paragraph (b).
In its 1987 RDL, NIOSH defined an APF as "[t]he minimum
anticipated protection provided by a properly functioning respirator or
class of respirators to a given percentage of properly fitted and
trained users" (Ex. 1-54-437Q). ANSI subsequently developed a
definition for an APF in its Z88.2-1992 Respiratory Protection Standard
that reads, "The expected workplace level of respiratory protection
that would be provided by a properly functioning respirator or class of
respirators to properly fitted and trained users" (Ex. 1-50). The ANSI
Z88.2 subcommittee that developed the 1992 standard used the NIOSH
definition of an APF as a template for its APF definition. However, the
Z88.2 subcommittee revised the phrase "minimum anticipated
protection" in the NIOSH definition to "expected workplace level of
respiratory protection." It also removed the NIOSH phrase "to a given
percentage" from its definition.
The phrase "a given percentage" implies that some respirator
users will not achieve the full APF under workplace conditions. The
"given percentage" usually is about five percent, which is a
percentage derived from statistical analyses of results from WPF
studies. In this regard, five percent represents the 5th percentile of
the geometric distribution of individual protection factors in a WPF
study. Therefore, the 5th percentile is the threshold for specifying
the APF for the respirator tested under those workplace conditions.
Using the 5th percentile means that about five percent of the employees
who use the respirator under these workplace conditions may not achieve
the level of protection assigned to the respirator (or class of
respirators), even after they receive proper fit testing and use the
respirator correctly under a comprehensive respiratory protection
program. However, ANSI dropped the phrase "to a given percentage" to
reduce confusion (i.e., the phrase did not specify a percentage), and
to emphasize the level of protection needed by the vast majority of
employees who use respirators in the workplace. See also subsection E.4
("Analysis of Updated Database on APRs") of Section III
("Methodology for Developing APFs for Respirators") of this preamble.
The Agency's review of the available data on respirator
performance, as well as findings from surveys of personal protective
equipment (Exs. 6-1 and 6-2), indicate that existing APF definitions
are confusing to the respirator-using public. Accordingly, OSHA has
developed its own definition in this final rule that will reduce
confusion among employers and employees regarding APFs, thereby
assisting employers in providing their employees with effective
respirator protection, consistent with its Respiratory Protection
Standard.
The major revision the Agency made to the ANSI APF definition in
developing the proposed APF definition included adding the phrase
"when the employer implements a continuing, effective respiratory
protection program as specified by 29 CFR 1910.134." The Agency added
this phrase to emphasize the already existing requirement that
employers must select a respirator in the context of a comprehensive
respiratory protection program. Also, the Agency revised the phrase
"as specified by 29 CFR 1910.134" at the end of the proposed APF
definition to read "as specified by this section" to conform to style
conventions for referencing an entire standard. Therefore, the Agency
is adopting the APF definition that was proposed in the NPRM except for
this minor revision. OSHA's final definition for APF reads as follows:
Assigned protection factor (APF) means the workplace level of
respiratory protection that a respirator or class of respirators is
expected to provide to employees when the employer implements a
continuing, effective respiratory protection program as specified by
this section.
B. APF Provisions
1. Paragraph (d)(3)(i)(A)--APF Provisions
Paragraph (d)(3)(i)(A) is the provision in OSHA's Respiratory
Protection Standard that requires employers to use the APFs in Table 1
of this final standard to select respirators. The language of the final
provision is the same as the language in the proposal. Therefore,
paragraph (d)(3)(i)(A) in the final rule reads as follows:
(A) Assigned Protection Factors (APFs). Employers must use the
assigned protection factors listed in Table 1 to select a respirator
that meets or exceeds the required level of employee protection.
When using a combination respirator (e.g., airline respirators with
an air-purifying filter), employers must ensure that the assigned
protection factor is appropriate to the mode of operation in which
the respirator is being used.
The proposed language in paragraph (d)(3)(i)(A) also contained the
following note that addressed two issues related to APFs:
Note to paragraph (d)(3)(i)(A): The assigned protection factors
listed in Table 1 are effective only when the employer has a
continuing, effective respiratory protection program as specified by
29 CFR 1910.134, including training, fit testing, maintenance and
use requirements. These assigned protection factors do not apply to
respirators used solely for escape.
The first sentence of the note was proposed to remind employers
that the APFs in Table 1 are effective only when they have a complete
respirator program that meets the requirements of OSHA's Respiratory
Protection Standard. Table 1 of the final rule already contains a note
(footnote 2) that essentially repeats this language. Therefore, to avoid
unnecessary duplication, the Agency decided to remove this language for
the final rule. However, the Agency is retaining the last part of the
note as a footnote in Table 1 of the final rule (see discussion of
footnote 5 in the following subsection).
2. Table 1--APF Table
The NPRM contained Table 1 ("Assigned Protection Factors"), which
listed the APFs for the various respirator classes. The final APFs for
these respirators are discussed in detail in subsection C ("Assigned
Protection Factors for Specific Respirator Types") of this section.
The proposed APF Table also contained a set of footnotes that
informed users regarding the application of APFs in the table. In the
final rule, footnote 1 remains essentially unchanged from the proposal.
Footnote 2 has been clarified to explain when APFs are effective,
rather than when APFs apply. All employers who use respirators need to
comply with the Respiratory Protection Standard. The language in
footnote 3 of the proposed table was revised from the proposal.
Proposed footnote 3 stated "This APF category includes quarter masks,
filtering facepieces, and half-masks." The reference to quarter masks
has been removed from this footnote since quarter mask respirators have
been assigned a separate APF in Table 1. Also, the phrase "with
elastomeric facepieces" has been added to the description of half
masks to clarify that elastomeric facepieces are included in the half
mask respirator class. Final footnote 3 reads as follows in the final
rule: "This APF category includes filtering facepieces, and half masks
with elastomeric facepieces."
Footnote 4 relates to the testing of PAPRs with helmets or hoods to
demonstrate that these respirators can perform at the required APF of
1,000 or greater for this class. The proposed footnote and the changes
made to it in the final standard are discussed in subsection C
("Assigned Protection Factors for Specific Respirator Types") in item
4 ("APF for Powered Air-Purifying Respirators (PAPRs)") of this
section.
Footnote 5 in the proposal described limitations for the APF of
10,000 (maximum) for pressure-demand SCBAs. The proposed footnote 5
described an SWPF study demonstrating that, when test subjects used
pressure-demand SCBAs under high work rates, a few of the study results
indicated that the respirators may not achieve an APF of 10,000.
Consequently, the proposed footnote cautioned employers not to use
these respirators under conditions that would require protection above
this level. In discussing this footnote in the proposal, OSHA stated
that, "the employer must restrict [pressure-demand SCBA] use to
conditions in which the required level of employee protection is at or
below an APF of 10,000" (68 FR 34105). While the Agency received no
comments on the proposed footnote, it believes that, when employers use
these respirators, they must assess the exposure conditions prior to
such use as required by paragraph (d)(1)(iii) of OSHA's Respiratory
Protection Standard. In view of the already existing requirement, the
Agency decided that the information in proposed footnote 5 was
unnecessary, and, therefore, removed it from the final rule.
As noted previously under subsection B ("Paragraph (d)(3)(i)(A)--
APF Provisions") of this section, OSHA is adding a new footnote 5 to
Table 1 in the final rule. The new footnote will remind employers that
they cannot apply the APFs specified in Table 1 to emergency-escape
conditions. OSHA believes this footnote is important because precise
exposures levels, which serve as the basis for determining APFs, cannot
be assessed accurately for emergency-escape conditions. Under these
conditions, the only appropriate respirators for employee use are
respirators designated for escape (i.e., escape respirators),
consistent with the requirements specified by OSHA's Respiratory
Protection Standard at 29 CFR 1910.134(d)(2)(ii). New footnote 5 is
similar to the APF provisions of the Agency's substance-specific
standards that designate appropriate respirators for use under
emergency-escape conditions. Because both the substance-specific
standards and 29 CFR 1910.134(d)(2)(ii) contain requirements for
selecting escape respirators, the Agency is revising the note slightly
to ensure that employers refer to the appropriate provisions.
Therefore, footnote 5 to Table 1 in the final rule will read as
follows:
These APFs do not apply to respirators used solely for escape.
For escape respirators used in association with specific substances
covered by 29 CFR part 1910 subpart Z, employers must refer to the
appropriate substance-specific standard in that subpart. Escape
respirators for other IDLH atmospheres are specified by 29 CFR
1910.134(d)(2)(ii).
C. Assigned Protection Factors for Specific Respirator Types
OSHA received comments on APFs during the public comment period
following publication of the NPRM, and at the public hearing. These
comments and hearing testimony are addressed in the following sections.
1. APF for Quarter Mask Air-Purifying Respirators
Introduction. OSHA proposed an APF of 10 for quarter mask air-
purifying respirators (i.e., quarter masks/quarter mask respirators),
including them in the same category as filtering facepieces and half
mask air-purifying respirators (68 FR 43115). However, the Agency
specifically requested comment on whether this action was appropriate
(see 68 FR 34112).
The following recommendations include all of the issues raised by
commenters regarding quarter mask respirators: assign them an APF of
10; assign them an APF of 5; prohibit their use altogether; or refrain
from assigning an APF to them until more studies become available. In
general, those commenters who recommended an APF of 10 for quarter mask
respirators based their recommendations on the analogous structural
characteristics (i.e., similarities in design) of quarter mask and half
mask respirators. Commenters who recommended an APF of 5 pointed out
that the only available APF data for quarter mask respirators were in
the 1976 study by Edwin C. Hyatt entitled "Respiratory Protection
Factors" (i.e., the "Hyatt Study" (Ex. 2)). Based on this study,
Hyatt assigned quarter masks an APF of 5.
Comments regarding quarter mask respirators. The commenters who
advised OSHA to give quarter mask respirators an APF of 10 believed
that when these respirators are used in a workplace where the employer
has implemented a complete respirator program as required by 29 CFR
1910.134, their performance should be the same as that of half mask
respirators. For example, Thomas Nelson of Nelson Industrial Hygiene
Systems, Inc. testified,
There is no unique property of a quarter mask respirator that
makes it[s] use different from half facepiece respirators provided
the person using the respirator is trained, fitted and maintains the
respirator. OSHA should include quarter masks in the half facepiece
category. (Ex. 10-17.)
Michael Runge of 3M Corporation recommended that both half mask and
quarter mask respirators should receive an APF of 10 because of their
similarity in performance, which he described as follows:
[L]eakage into a respirator can occur through three pathways[:]
defects, filter penetration or faceseal leakage. Leakage through
defects is controlled by the respirator maintenance program. Quarter
facepiece respirators are no harder to maintain than half facepiece
respirators; they have many of the same parts * * * Filter leakage
is controlled by the NIOSH certification process * * * Faceseal
leakage is controlled through fit testing. The same fit tests can be
used with either type of respirator, hence the same maximum face
seal leakage would be expected for the quarter and half facepiece
respirator. (See Ex. 9-16.)
Daniel Shipp and Janice Bradley of the International Safety
Equipment Association and Kenneth V. Bobetich of MSA made similar
statements (Exs. 9-22, 9-37, and 16-14).
Thomas Nelson asserted that the Hyatt Study may have underestimated
the APF for quarter mask respirators because the study did not control
adequately for respirator leakage. His comment was based on the fact
that the authors of the study: (1) Did not administer a proper fit test
to the test subjects prior to measuring particle contamination inside
the respirator, and (2) used a fine particle (sodium chloride) as a
test aerosol, that may have penetrated both the faceseal and filter,
thereby artificially increasing concentrations inside the respirator
(Tr. at 163 and Ex. 18-9).
The commenters who recommended that OSHA assign quarter mask
respirators an APF of 5 stressed that no studies, including WPF and
SWPF studies, on quarter mask respirators have been performed since the
Hyatt Study. Few quantitative data are thus available on which OSHA can
rely to set an APF for quarter mask respirators. These commenters, who
include NIOSH, pointed out that NIOSH used the Hyatt Study to set the
APF for quarter mask respirators at 5 in its 1987 RDL. NIOSH commented
further that, "quarter mask respirators should be separated from half
mask respirators into a class of their own with an APF of 5. The data
from Hyatt's study [1976] do not support an APF of 10" (Ex. 17-7-1).
Similarly, James S. Johnson stated, "We object to the agency's
proposed APF of 10 for quarter mask respirators. There is no evidence
in the record, from either WPF or simulated workplace protection factor
(SWPF) studies that support this conclusion" (Ex. 16-9-1). Johnson's
comments were echoed by the AFL-CIO (Exs. 9-27 and 19-1-1). These
comments indicate that the Hyatt Study was not a valid WPF or SWPF
study because it was a fit test protocol, not an experimental study.
The International Brotherhood of Teamsters and the AFL-CIO Building
and Construction Trades Department supported an APF of 5 for quarter
mask respirators because they believed that quarter mask respirators
were more likely than half mask respirators to move around on workers'
faces when the workers communicate, or because of movement, exertion,
or perspiration. These commenters stated:
Since the lower seal of the facepiece in quarter mask
respirators is on the chin, rather than below the chin, the seal is
much more likely to be compromised than the seal on a half face
respirator. Additionally, in use factors such as movement, exertion,
and perspiration add to the likelihood that the seal of these masks
will be compromised in the work place. (Exs. 9-12 and 9-29.)
The Nuclear Regulatory Commission commented that its regulations
prohibit the use of quarter masks because of "the potential lack of
stability of fit and the availability of acceptable alternatives (half-
face respirators)" (Ex. 10-7). Tracy Fletcher of Parsons-Oderbrecht JV
recommended that OSHA prohibit the use of both quarter and half masks,
stating, "Employees are required to wear eye protection with the
respirator, and use of the two together is difficult as the wearer will
find that the glasses rest on the nose piece of the respirator creating
an entry point for an overspray, splash or whatever." (Ex. 10-1.)
A small number of commenters expressed the opinion that, because
the Hyatt Study provides the only data on the protection afforded by
quarter mask respirators, OSHA should reserve its decision on the APF
for these respirators until more studies can be completed. ORC
Worldwide commented that "[q]uarter masks should be evaluated as
individual respirator models. In the absence of comprehensive testing
data over the last 27 years, there is no valid basis for giving them an
APF of any kind" (Ex. 10-27). David Spence, an industrial hygienist,
stated:
We recommend that SWPF studies be performed on quarter masks
respirators in a manner analogous to the ORC SWPF studies performed
on powered air-purifying respirators and supplied-air respirators.
To not delay publishing APFs for the other classes of respirators,
the section on APF of quarter masks could be reserved pending
completion of SWPF studies. (Ex. 10-6.)
Summary and conclusions. In light of these comments, the Agency has
reconsidered the proposed APF of 10 for quarter masks. The comments
recommending an APF of 10 for quarter mask respirators are based solely
on structural analogies between quarter masks and half masks, and not
on the functional characteristics of these respirators. Accordingly,
the rulemaking record contains no quantitative or qualitative data or
other convincing evidence confirming that quarter mask and half mask
respirators function in a similar fashion to provide employees with
equal levels of respiratory protection. No WPF or SWPF studies
conducted on quarter mask respirators were submitted to the record. The
Hyatt Study, which consisted of testing quarter masks using a fit
testing protocol, provides the only data available for quarter mask
respirators, and it supports an APF of 5. Therefore, OSHA has decided
to separate quarter mask respirators into their own category and assign
them an APF of 5.
It is possible that the facepieces of quarter masks and half masks
are not functionally analogous. Some commenters noted that half masks
rest under the chin while quarter masks rest on the chin. Consequently,
quarter masks are more prone than half masks to slip and compromise the
face seal when a worker talks or performs heavy work. While the record
contains no quantitative evidence supporting such assertions, there is
ample qualitative evidence, and OSHA is entitled under these
circumstances to take a conservative approach in weighing the available
evidence (see, e.g., 29 U.S.C. 655(b)(5) and United Steelworkers of
America, AFL-CIO-CLC v. Marshall, 647 F.2d 1189, 1248 (D.C. Cir.
1980)). Moreover, OSHA believes that these respirators can be used
safely at an APF of 5 because properly administered fit testing
protocols (including administering the fit test with glasses and other
protective equipment worn during respirator use),\9\ as well as
appropriate respirator training, will inform employees of this problem
and the procedures they can use to prevent it.
---------------------------------------------------------------------------
\9\ As required under Appendix A (Part IA, paragraph 13) of 29
CFR 1910.134.
---------------------------------------------------------------------------
In further response to those commenters who advised OSHA to
prohibit quarter masks, OSHA does not believe that this approach is
reasonable. As discussed at the public hearing, quarter mask
respirators are not widely used, but they do have some popularity in
particular industries (Tr. at 558). All existing quarter mask
respirators have received an N95 rating under NIOSH's certification
program, indicating that the respirators are designed to prevent at
least 95% of the challenge agent from penetrating the filter.
Therefore, these certification results, along with the other evidence
in the rulemaking record, have convinced OSHA that employees can use
these quarter mask respirators safely at an APF of 5 in workplaces that
implement a respirator program that complies with 29 CFR 1910.134.
Regarding those commenters who advised OSHA to delay the APF
decision for quarter mask respirators until WPF or SWPF studies are
available, OSHA notes that in the intervening 29 years following the
Hyatt Study, no WPF or SWPF studies have been conducted on quarter mask
respirators. If OSHA was to delay setting an APF for quarter mask
respirators pending further study, it could in effect be deciding to
delay setting an APF for these respirators indefinitely. OSHA has not
been persuaded by the record to delay setting an APF for quarter mask
respirators. Moreover, as noted in the previous paragraph, OSHA has
concluded that the record evidence supports an APF of 5 for quarter
mask respirators.
2. APF for Half Mask Air-Purifying Respirators
Introduction. OSHA proposed an APF of 10 for both elastomeric and
filtering facepiece half mask respirators. During the public comment
period, interested parties expressed two divergent views on this
proposed APF. The healthcare industry (Ex. 9-18 to 9-21), NIOSH (Tr.
107 and 112) and other commenters (e.g., Exs. 9-11, 9-22, 9-26, 9-42,
and 10-18) agreed to an APF of 10 for both types of respirators, while
a number of commenters stated that filtering facepieces should be
assigned a protection factor of 5 (e.g., Exs. 9-8, 9-12, 9-29, and 10-
6; AFL-CIO Tr. at 122-126). The following sections discuss this issue
in detail.
A number of reasons were presented for limiting filtering facepiece
half masks to an APF of 5. These reasons can be categorized generally
into concerns related to: (1) WPF studies and associated data; (2)
design of filtering facepiece respirators; (3) respirator use in the
workplace; and (4) ANSI standards. As discussed in Section III above,
some commenters believed that the WPF studies evaluated by OSHA
suffered from multiple problems (e.g., old data, studies not
representative of typical workplaces). While these points are addressed
in detail in Section III of this preamble, some of these concerns
warrant further discussion here.
Some filtering facepieces do not achieve an APF of 10. Comment was
made that the data presented in the studies analyzed by OSHA indicate
that not all filtering facepieces achieved an APF of 10. Consequently,
these commenters argued that the entire class of respirators should
receive an APF of 5 (Exs. 9-29, 9-27, and 10-54). The AFL-CIO stated:
An examination of the summary table of WPF studies for filtering
facepieces and half-mask elastomeric respirators at 68 FR 30495 of
OSHA's preamble to this proposed rule justifies our position. Of the
seven respirators that had a 5th percentile WPF less than 9, five of
[the] respirators that failed consisted of the filtering facepiece
style of respirator. Thus [of] the overwhelming majority of the half
mask respirators that failed, five of the seven or 71%, were
filtering facepieces. At the qualitative level then, this data
clearly indicates that most of the problem with failing to provide
adequate protection rests with filtering facepieces and not with
half-mask elastomerics. (Ex. 9-27.)
The summary table in the proposal at 68 FR 34095 contains several
studies that were reviewed by OSHA, but did not meet the selection
criteria and were excluded from the quantitative analyses. The two
filtering facepiece respirators (one model in each study) evaluated in
these excluded studies had WPFs less than 9 (Cohen, Ex. 1-64-11; and
Reed, Ex. 1-64-61), while five of the respirators included in OSHA's
analyses failed to achieve a WPF of 9. Three of these five respirators
were filtering facepiece respirators and the remaining two respirators
were elastomeric half masks. As noted at the hearing, OSHA conducted a
Chi-square analysis to determine if the proportion of filtering
facepieces having a WPF less than 9 differed from the proportion of
elastomerics with a WPF less than 9 (Trans. at 135-136). This
statistical comparison showed that these proportions did not differ
significantly from each other, indicating that similar proportions of
filtering facepiece and elastomeric respirators performed at this
level--i.e., that the filtering facepiece respirators did not perform
more poorly than the elastomeric respirators.
After updating the proposal's half mask WPF database (Ex. 20-2)
with new and additional data, Dr. Crump reanalyzed the database (Ex.
20-1). Plotting the observed protection factors for both the
elastomeric and the filtering facepiece half masks shows that over 95%
of each type of half mask attained an APF of at least 10. Moreover, a
review of these updated analyses reveals that more elastomeric than
filtering facepiece respirators failed to achieve an APF of 10 (see
Table 2 in Ex. 20-1). Even when the data from studies excluded from
these analyses were added to the database, over 95% of the WPFs for
both types of half mask (separately and combined) are still equal to or
greater than 10. (A detailed discussion of Dr. Crump's analyses can be
found in section III (Methodology) of this preamble.) Therefore, OSHA
does not agree that the evidence in the record supports an APF for
filtering facepieces of 5 as suggested by these commenters.
Respirator configuration and certification issues. Commenters also
stated that not all configurations (e.g., cups, duckbills, fold flats)
of filtering facepiece respirators have been studied (e.g., Exs. 9-17,
9-34, 9-40, 10-33, and 10-34; Tr. at 204-205). In addition, some
commenters mentioned that none of the respirators in the studies
evaluated by the Agency for the proposal were certified under NIOSH's
new 42 CFR 84 requirements (Exs. 9-33, 9-34, 10-22, and 10-38). The
focus of these comments was that OSHA should not assume that all
filtering facepieces perform the same as those filtering facepieces
that were tested. These commenters believed that filtering facepiece
half masks should be given an APF of 5 because, in their view, there is
a lack of information on 42 CFR 84 filtering facepieces.
OSHA recognizes that its analyses do not encompass all
configurations or models of filtering facepiece half masks. However,
this is true for all types of respirators, not just filtering facepiece
half masks. Since filter efficiency is certified by NIOSH, the filter
media of all filtering facepiece (and elastomeric) half mask
configurations are equivalent. Therefore, any differences in
performance would arise from variations in faceseal leakage among the
different configurations. OSHA's Respiratory Protection Standard
requires that all respirator users pass a respirator fit test to ensure
that a minimum acceptable faceseal performance is achieved. Therefore,
because all respirators must be used in accordance with the Respiratory
Protection Standard, the Agency sees no reason to conclude that
differences in configuration will result in performance variations. In
addition, Section III of this preamble discusses two studies that
compare the workplace performance of 42 CFR 84 and 30 CFR 11 filtering
facepiece half masks. The 42 CFR 84 respirators demonstrated superior
performance when compared to the 30 CFR 11 respirators. OSHA concludes
that, based on the more stringent filter efficiency certification
requirements and these study results, 42 CFR 84 respirators provide
performance at least equal to 30 CFR 11 respirators. Therefore, the
record evidence does not support lowering the APF for filtering
facepieces to 5.
Determining faceseal leakage. Several commenters mentioned that
NIOSH had eliminated the fit test portion of its certification
procedures. They believed that as a result of this NIOSH action, one
could not be sure if a filtering facepiece respirator achieves an
adequate faceseal and provides the expected protection (Exs. 9-8, 9-27,
9-29, 9-34, 9-35, 9-40, 9-41, 10-22, 10-33, 10-38, 10-50, and 10-55).
During the public hearing, NIOSH indicated that it would establish a
new respirator certification testing procedure, stating:
Such changes would result in additional certification tests to
assure or assess the overall performance of every respirator model,
and thus assure that every model is capable of providing a level of
protection consistent with the class APF. (Tr. at 103.)
Several commenters supported this approach, and indicated that
implementing such a procedure would be beneficial. For example, Tim
Roberts (Exs. 17-8 and 18-4) stated that the procedure would help to
identify respirators that may not have adequate workplace performance.
The AFL-CIO (Ex. 19-1) believed that while the procedure would help
assure certified filtering facepieces are capable of fitting an
employee properly, these respirators should still be given an APF of 5.
Two respirator manufacturers also addressed this issue. The 3M
Company commented that no evidence exists showing that employee
protection would be enhanced by adding a fit test requirement to
NIOSH's certification procedures, and added that proper respirator fit
must be determined by fit testing each wearer (Ex. 18-7). When asked by
OSHA about the proposed NIOSH testing, Jay Parker of Bullard responded
that he believed such testing would be an improvement over the current
procedures (Tr. at 497).
OSHA has reviewed this information and supports NIOSH's plans to
add performance testing to its respirator certification procedures. The
Agency agrees with the 3M Company that proper facepiece fit can only be
assured through individual fit testing. However, OSHA also agrees with
Tim Roberts that performance testing will assist in identifying
respirators with poor fitting characteristics that may not provide
protection consistent with the respirator's APF. Thus, OSHA concludes
that performance testing will enhance the information needed for
selecting appropriate respirators, and encourages NIOSH to expedite its
efforts in this area. However, employers and respirator users should
note that using a respirator certified by NIOSH through performance
tests would not preclude individual fit testing as required by OSHA's
Respiratory Protection Standard.
Filtering facepiece design problems. Several commenters urged an
APF of 5 for filtering facepiece half masks based on the design
characteristics of these respirators. Some commenters expressed concern
that, in comparison to elastomeric half masks, filtering facepieces are
poorly constructed (e.g., non-adjustable head straps, prone to crushing
or denting, facepiece too stiff or too soft) (e.g., Exs. 9-34, 10-37,
10-38, 10-54, and 12-7-1). For example, T.C. Lefford of Fluor Hanford
stated:
Elastomeric half-mask respirators provide a better face seal
that filtering facepieces (Disposable respirators or maintenance-
free masks). Most elastomeric half-mask respirators are made of more
pliable silicone rubber that provides a much better seal on the
face. Elastomeric half-mask respirators have three sizes with
adjustable head straps and a head cradle to improve stability while
the majority of filtering facepieces have one or two sizes and the
head straps are non-adjustable. (Ex. 9-32.)
OSHA believes that concerns about loose, dented, or crushed
filtering facepieces are addressed adequately by compliance with
existing program requirements under 29 CFR 1910.134(d) and (g).
In addition, comment was received alleging that the 42 CFR 84
requirements for increased filter efficiency result in respirators with
stiff facepieces, poor face seals, and high breathing resistance,
thereby producing filtering facepieces with increased faceseal leakage
(e.g., Exs. 9-34, 9-41-1, 10-46, and 10-50). Mark Haskew, Tim Roberts,
and Ching-tsen Bien (Exs. 12-7-1, 16-12, 16-20-3, and 17-5) also
expressed concern about the increased filter efficiency requirements of
the new 42 CFR 84 certification standards and their effect on the
performance of filtering facepiece respirators. In their written
comments, Mark Haskew and Tim Roberts stated that the 42 CFR 84 filter
efficiency requirements "would increase the breathing resistance and
in turn cause an increase in faceseal leakage when compared to 30 CFR
part 11 filtering facepieces" (Ex. 12-7-1). Haskew, Roberts and Bien
also questioned the ability of 42 CFR 84 filtering facepieces to fit
the user's face, and the applicability of 30 CFR part 11 study data to
42 CFR 84 respirators. For example, Mark Haskew testified:
The other problem with the old data is that the 30 CFR 11
respirators are significantly different in performance, or at least
we would anticipate that they may be different in the performance
that they provide. Based on the newer filter media with the 95, 99
and 100 series, there's an allowance for increased breathing
resistance. And because the efficiency has to be greater, the filter
media itself tends to be stiffer. And the concern we have, of
course, which is untested in the research as far as we know, is that
it may not conform as well to a wearer's face. (Tr. at 203.)
Based on their opinion that manufacturers would have to produce
thicker, stiffer filter media to meet the new filter efficiency
requirements, these commenters concluded that the data for 42 CFR 84
filtering facepieces would show a decrease in performance compared to
the older 30 CFR 11 respirators. These commenters, based on this
assumption, concluded that it would be inappropriate to set the APF for
filtering facepieces based on WPF studies of the older 30 CFR 11
respirators. However, they presented no data to substantiate this
claim.
When NIOSH published the 42 CFR 84 respiratory protective devices
final rule (60 FR 30336), Section 84.180 of this rule increased the
maximum allowable breathing resistance levels during inhalation to 35
mm (of water pressure), and during exhalation, to 25 mm. NIOSH
explained this increase as follows:
[It will] enable manufacturers to produce respirators meeting
the new requirements more expeditiously and at lower cost. * * *
This small increase in maximum allowable breathing resistance for
particulate respirators does not add substantially to physiologic
burden for respirator users, and will be compensated for by
increased worker protection provided by the new filter efficiency
tests and classification system. (60 FR 30346.)
However, when respirator manufacturers developed new particulate
filters to meet the 42 CFR 84 performance requirements, they were able
to meet them without increasing the breathing resistance levels. For
example, the 3M Company submitted the following table of breathing
resistance values for several classes of 42 CFR 84 filters made by
different manufacturers (Ex. 17-9-1, page 6; derived from a paper
submitted by 3M to the OSHA docket (Ex. 9-16-1-3)).
------------------------------------------------------------------------
Manufacturer A Manufacturer B
Filter Class ([Delta]P mmH2O) ([Delta]P mmH2O)
------------------------------------------------------------------------
N95............................. 11.5.............. 9.7
R95............................. No Product........ 13.6
P95............................. 14.9.............. No Product
P100............................ 23.9.............. 17.3
------------------------------------------------------------------------
No measurement in this table exceeds the 30 CFR 11 limit of 30 mm
of water pressure. As the 3M Company stated, "Breathing resistance of
42 CFR 84 respirators are contained within the range of breathing
resistances allowed for 30 CFR 11 respirators, rather than being
significantly higher" (Ex. 16-25-2, page 17).
OSHA also received comments that higher breathing resistance leads
to increased faceseal leakage (Exs. 9-34, 9-35, 9-41, 10-38, and 10-
50). During the public hearings, 3M submitted two new studies of
filtering facepiece respirators certified under 42 CFR 84 (Ex. 16-25-
3). The 42 CFR 84 certified filtering facepieces used in these studies
performed better, overall, than comparable filtering facepieces
certified under 30 CFR 11 (see discussion above under Section III
("Methodology, etc.")). These results indicate that faceseal leakage,
if it existed, did not impair the performance of these filtering
facepieces.
At the 2004 AIHCE in Atlanta, Georgia, Larry Janssen of the 3M
Company presented the results of a recently completed study (Ex. 17-9-
1) using the OHD FitTester 3000 controlled negative pressure (CNP) fit
testing instrument to measure faceseal leak rate (i.e., a drop in
pressure inside the mask). Leak-rate measurements first were made using
the negative pressure and flow-rate settings listed for the CNP fit
test in Appendix A of 29 CFR 1910.134. Without disturbing the fit of
the respirator, four additional leak-rate measurements then were made
at four different negative pressures and flow rates ranging from 5.6
through 20.1 mm of water pressure, followed by a final measurement at
the CNP fit test rates. Janssen found that test subjects with a fit
equal to or greater than a fit factor of 100:
[D]id not show any increase in leak rate as pressure drop
increased. Subjects with a fit factor below 100 * * * showed
significant variability in leakage as the settings were changed, but
the amount of leakage did not correlate with increasing pressure
drop, i.e., sometimes the leakage was higher and sometimes lower.
(Ex. 18-7, page 49.)
The 3M Company concluded that the study "demonstrates the value of
fit testing: respirators that fit well enough to be assigned to a
worker do not exhibit increased leakage as pressure drop increases"
(Ex. 18-7, page 49). Janssen, in a summary of this study that he
presented at the May 2004 AIHCE stated, "Results of this study do not
support the concept of increased faceseal leakage with increased
pressure drop."
While concern was expressed by some commenters about increased
filter efficiency requirements resulting in increased breathing
resistance and faceseal leakage, no data were submitted to support this
viewpoint. However, studies were submitted that demonstrated that 42
CFR 84 filtering facepiece respirators perform at least as well as 30
CFR 11 filtering facepieces, and that increased filter efficiency does
not result in increased faceseal leakage. After reviewing this
information, OSHA is persuaded that 42 CFR 84 half masks are as
protective as 30 CFR 11 half masks and that increased face seal leakage
in such respirators has not been demonstrated by evidence in the
record. Therefore, these arguments do not support an APF for filtering
facepieces of 5.
The efficacy of user seal checks provided by respirator
manufacturers also was questioned by several commenters. These
commenters stated that user seal checks for filtering facepieces either
could not be performed or were more difficult than user seal checks
with elastomeric facepieces (e.g., Exs. 9-27, 9-31, 9-34, 9-35, 9-40-1,
9-41-1, and 10-54). In general, their opinion was that the inability to
perform an adequate user seal check on filtering facepiece respirators
would lead to decreased protection, thereby warranting a reduced APF
for this type of respirator.
Bill Kojola of the AFL-CIO (Exs. 9-27 and 19-1) stated that "user
seal checks are rarely performed on filtering facepieces in the field
and * * * it is extremely difficult, if not impossible, to perform
effective user seal checks on filtering facepieces." He stated that it
was "easy for wearers to perform effective user seal checks on
elastomerics." Kojola cited this difficulty in performing user seal
checks as a reason for separating filtering facepieces from
elastomerics, and giving filtering facepieces an APF of 5. However, he
did not provide any data to support his experience that filtering
facepieces demonstrate a difference in user seal check performance
compared to elastomerics.
Similar concerns were voiced by Mark Haskew (Exs. 17-5 and 18-3),
Tim Roberts (Exs. 9-8, 10-55, and 17-8), and Ching-tsen Bien (Exs. 9-
43-2 and 18-5). In addition, Mark Haskew stated that filtering
facepieces with adjustable nose pieces cannot normally obtain
repeatable fit factors. However, these commenters did not submit any
supporting data for this contention. In his post-hearing submission,
Tim Roberts (Ex. 18-4) stated that data demonstrating this difference
in performance are not available.
James Johnson (Exs. 10-33, 16-9-1, and 17-10) also stated that
filtering facepieces cannot be fit checked effectively, and presented
results from a series of fit tests he performed on himself with
filtering facepieces and elastomeric half masks. Three of the four
elastomeric half masks that he tested passed a positive or negative
user seal check, and consistently achieved a fit factor of 1500 or more
using the Portacount fit test instrument. One elastomeric half mask did
poorly (fit factor of less than 100), and it was identified clearly as
a failure by a user seal check and a subsequent fit test. He found that
it was difficult to achieve a minimum fit factor of 100 or greater with
filtering facepieces using the Portacount Companion fit test
instrument. However, two of the eight filtering facepiece models he
tested achieved fit factors of 100 or greater. He stated that he was
able to identify obvious leaks with the filtering facepieces he tested
by exhaling heavily and sensing the airflow, but that cupping his hands
over the facepiece was not an effective user seal check for him. He
stated further that these preliminary fit test results demonstrated a
significant difference in performance between elastomeric and filtering
facepiece half masks, and that OSHA should give filtering facepieces an
APF of 5 based on these results.
The numerical differences in fit factors between filtering
facepieces and elastomeric half masks reported by Johnson may not be
significant. Achieving a fit factor of 170, as Johnson did with the 3M
9211 foldable filtering facepiece using the Portacount Companion, is not
necessarily worse than achieving a fit factor of 2200 with a MSA Comfo
elastomeric half mask using the Portacount alone. In this regard, the
fit test instruments identified the elastomeric half masks and filtering
facepieces that provided adequate fits on Johnson (i.e., they met their
required fit factor of 100), and he was able to perform user seal checks
with both respirators. Therefore, OSHA finds that these fit test measurement
differences are not a convincing argument for an APF for filtering
facepiece respirators of 5. The Agency believes that Johnson's pilot
study proves only that some makes and models of filtering facepieces
are not suitable for his face size and shape. When he wore a filtering
facepiece or elastomeric respirator that fit him, an APF of at least 10
was achieved.
In response to these concerns, the 3M Company (Ex. 17-9-2) and the
Aearo Company (Ex. 17-3-1) submitted to the record instructions for
conducting user seal checks on their filtering facepiece respirators.
The Aearo Company instructs users to cup their hands over the
respirator to test the seal, stating: "If air flows around your nose,
tighten the nosepiece; if air leaks around the edges, reposition the
straps to fit better (Ex. 17-3-1)." User seal check instructions for
3M filtering facepieces read, "If air leaks between the face and
faceseal of the respirator, reposition it and readjust the nose clip
for a more secure seal" (Ex. 17-9-2).
In their post-hearing comments (Exs. 9-16, 17-9-1, 18-7, and 19-3),
3M responded to the comments raised at the public hearing regarding the
difficulty or impossibility of performing user seal checks on filtering
facepiece respirators. The 3M Company pointed out that no data were
offered to support this position, nor was recognition given to the
methods contained in both the 1980 and 1992 editions of the ANSI Z88.2
respirator standard for performing user seal checks. The 3M Company
also cited a study in the docket by Myers et al. (Ex. 9-16-1-13), which
concluded that no difference was found in the effectiveness of
performing user seal checks on filtering facepiece respirators or
elastomeric respirators. This study also referenced a comment by Daniel
K. Shipp of the ISEA (Ex. 9-22) that user seal checks can be performed
with filtering facepieces. A second evaluation of user seal checks
submitted by 3M (Ex. 17-9-10) involved the use of a 3M flat-fold
filtering facepiece by novice respirator users. It showed that novice
respirator users can be trained to effectively perform user seal
checks, and that the use of seal checks improved the overall quality of
respirator fit.
The 3M Company also stated that the ease or difficulty in
performing user seal checks is based on many factors. These factors
include difficulty in performing a user seal check on some elastomeric
respirators when the exhalation valve cover must be removed without
disturbing the fit. Also, it can be difficult to perform a user seal
check on elastomerics by blocking off the filter when a respirator user
has small hands. In addition, 3M cited an analysis from its report at
the 2001 AIHCE (Ex. 4-10-7) that showed no significant differences in
WPF results for filtering facepieces measured in the morning and
afternoon, with repeated redonnings of the respirators performed during
each of these periods. These results indicate that the user seal check
conducted after each redonning was effective in ensuring proper
respirator fit.
During the rulemaking, several commenters referred to the use of
fit check cups to perform user seal checks. These devices are designed
to assist the respirator user in performing a positive and negative
pressure seal check by covering the surface of a filtering facepiece
respirator. For example, Tim Roberts stated:
One of the manufacturers did recognize that there was difficulty
in doing these types of fit checks, and they designed, and
constructed, and sold a fit-check cup that actually fit over the
facepiece of a respirator, a filtering facepiece respirator, so that
it would actually check the seal in a more conventional manner. We
think that that may be another alternative approach to assuring that
these respirators fit properly if there was a requirement to do
that. (Tr. at 216.)
Another commenter who discussed the use of fit check cups was
Donald Faulkner of the United Steelworkers, who stated during his
questioning of Warren Myers:
[W]e don't see a real good fit with the hands-over filtering
facepiece. That's why the cups were developed by many manufacturers,
but we don't see them being utilized, bought, or anything else. (Tr.
at 95.)
He elaborated in his post-hearing comment: "Filtering facepieces
do not allow seal checks to be performed without the assistance of
additional equipment [i.e., fit check cups] that is never provided by
the employers, as being cost prohibitive." (Ex. 19-2.)
Bill Kojola of the AFL-CIO (Tr. at 132) and George Macaluso of the
Building Construction Trades Department of the AFL-CIO (Tr. at 654)
made similar statements regarding the infrequent use of fit check cups,
i.e., that they are generally not used in the workplaces their unions
represent. They asserted that user seal checks that involve cupping the
hands over the facepiece were not effective, and that the use of fit
check cups should be required by OSHA. They implied that fit check cups
are a generic device for doing user seal checks, and that one
manufacturer's fit check cup can be used with other types of filtering
facepieces. On the other hand, Ken Wilson of the Ohio Board of Water
Quality, Division of Safety and Hygiene (Ex. 10-3) stated that he has
not seen fit check cups used in the field, and doubted that their use
would allow a respirator user to achieve a successful fit check.
OSHA has considered carefully the opinions presented about fit
check cups and user seal checks. The Agency recognizes that the use of
a fit check cup is one way of performing a user seal check. However,
these cups can be inconvenient when used in the workplace on a daily
basis. In this regard, each respirator user would need ready access to
a fit check cup, not only to perform the required user seal checks when
initially donning the respirator, but for any repeated respirator
donnings that occur throughout the workday. The fit check cup would be
another piece of equipment for respirator users to carry with them, and
it can be misplaced. However, most respirator manufacturers have not
adopted the use of fit check cups, and these manufacturers recommend
cupping the hands over the filtering facepiece to perform a user seal
check. As the 3M Company stated in describing the use of fit check
cups, "Based on our experience, user seal checks without cups are
effective, more convenient, and easier to perform" (Ex. 17-9-1, page
4).
Since only a few respirator manufacturers have fit check cups, it
is not surprising that they are seldom used in the workplace. The fit
check cups that exist are designed by the respirator manufacturer to
work with a specific facepiece configuration and respirator model, and
the cups do not necessarily work with other models of respirators, even
models made by the same manufacturer. OSHA knows of only one series of
42 CFR part 84 filtering facepiece respirators that have fit check cups
available.
OSHA does not find merit in the comments that fit check cups are
necessary to perform user seal checks with filtering facepieces. While
a fit check cup designed to work with a particular model of respirator
can be used to perform a user seal check, it is not the only way to
perform this function. Accordingly, the Agency believes that respirator
users can follow a respirator manufacturer's instructions to perform a
user seal check, e.g., whether the seal check involves cupping the hands
over the facepiece or the use of a fit check cup.
The OSHA Respiratory Protection Standard requires that an employee
perform a user seal check to use a respirator. The WPF database that
OSHA developed contains over 1,000 WPF data points for half mask
respirators collected from workers using respirators in programs that
included user seal checks. Analyses of these data showed that the
filtering facepiece respirators achieved an APF of 10. These data are
derived from WPF studies in which user seal checks were performed on
filtering facepiece respirators by 100s of workers. In addition, 3M's
analysis (Ex. 4-10-7) indicates that user seal checks performed on
filtering facepieces ensure proper redonning of these respirators. When
a respirator user cannot perform a user seal check with a particular
respirator model, then that respirator cannot be used by that employee,
and the employer must find another respirator model on which a user
seal check can be performed. This requirement applies to all tight-
fitting facepieces, including filtering facepieces and elastomeric half
masks. How easy or difficult it is for an employee to perform a user
seal check on a particular type of respirator is not an issue that
precludes other employees from using that respirator. Therefore, the
comments on user seal checks do not provide convincing evidence that
would support decreasing the APF for filtering facepieces to 5.
OSHA argued previously in National Cottonseed Products Association
v. Brock, 825 F.2d 482 (D.C. Cir. 1987) that filtering facepieces used
to protect employees against exposure to cotton dust should have an APF
of 5 based on the difficulty of fit testing, particularly fit checking
on a daily basis. However, the Agency now believes that the record
evidence for this rulemaking shows that the industrial-hygiene research
community has developed and refined qualitative and quantitative fit
tests, as well as developed sophisticated techniques for determining
respirator leakage. Several commenters (Exs. 16-25-3 and 17-9-1)
provided evidence that filtering facepieces could be fit tested and
then used effectively. Seal-check techniques and procedures (e.g., fit-
test cups, manual testing) also have been developed to help ensure that
filtering facepieces maintain their fit while being worn in the
workplace. These new developments allowed the Agency to reassess
filtering facepieces and find that these respirators can be reliably
fit tested and fit checked.
The WPF studies provide further support for this conclusion. In
fact, every WPF study of filtering facepieces in the OSHA APF database
involved fit testing the respirator, using the new and refined methods,
prior to the worker using the respirator in the study. Researchers used
the available fit testing and checking technologies and methodologies
in the studies to be assured that employees would be protected during
the study by the respirators when exposed to airborne contaminants up
to 10 times the PEL, and so that they could determine the results of
the study would be accurate.
Non-compliance and economic incentive issues. Several commenters
asserted that filtering facepiece half masks should be given an APF
less than 10 because employers do not comply with the Respiratory
Protection Standard (e.g., by not performing fit testing) (e.g., Exs.
9-40-1, 10-33, and 10-52; Tr. at 663). In this regard, Donald Faulkner
of the United Steelworkers of America (USWA) stated:
We observe in many worksites that the employers are issuing
filtering masks as if they were candies. They don't have respiratory
protection programs, requirements to be clean shaven, and no medical
or no idea of the MUC of the contaminant that the worker needs to be
protected from. (Ex. 9-40-1.)
However, the 3M Company commented that non-compliance with the
Respiratory Protection Standard should not be a factor in determining
APFs, noting:
OSHA has appropriately made the proposed APFs contingent upon
the existence of an effective and well-managed respiratory
protection program. This is the only circumstance under which APFs
can be used. Setting APFs on assumptions of poor fit and lack of
training is impossible because of the countless variables that exist
in the workplace and workforce. APFs can only apply under properly
managed respiratory protection programs. This is supported by
following the American Industrial Hygiene Association Respiratory
Protection Committee definition of APFs: An APF is the level of
respiratory protection that a properly functioning respirator or
class of respirators would be expected to provide to properly fitted
and trained users in the workplace. The APF takes into account all
expected sources of facepiece penetration (e.g., face seal
penetration, filter penetration, valve leakage). It is not intended
to take into account factors that degrade performance such as poor
maintenance, failure to follow manufacturers' instructions, and
failure to wear the respirator during the entire exposure period.
(Ex. 9-16.)
Several commenters voiced concern that assigning a protection
factor of 10 to both elastomeric and filtering facepiece half masks
will result in an economic incentive for employers to provide filtering
facepiece respirators to employees rather than elastomeric half masks.
These commenters assumed that the less expensive filtering facepiece
respirators were less protective than the more expensive elastomerics
(e.g., Exs. 9-29, 10-38, and 10-54; Tr. at 212-213 and 659-660). The
USWA expressed this concern, stating, "If OSHA gives the filtering
face piece type of respirator an APF of 10, employers would interpret
this as `let's take the cheap way out.' It will be a dis-incentive to
issue to workers the proven protection of the elastomeric face piece
respirator" (Ex. 9-40-1). Responding to an OSHA question about this
issue, Thomas O'Connor of the National Grain and Feed Association
stated:
Well, clearly, if [you] had two respirators that provided the
comfort and fit to the employee that's needed and one was half the
cost of the other one, obviously anybody would select the lower cost
respirator. But as I noted, that's not the primary motivation, cost.
The primary motivation is complying with the standard, making sure
that the employee[s] wear it and it fits properly and it's
comfortable. * * * If an employee's wearing a respirator that's not
comfortable, there's going to be an incentive for them possibly not
to wear that respirator * * * when they should be wearing it. So
from our perspective, comfort is one of the primary considerations
in selecting a respirator for an employee. (Tr. at 684-685.)
OSHA considered these comments and concludes that neither cost nor
non-compliance with the Respiratory Protection Standard is an
appropriate basis for determining the final APF for half masks.
Employers are required to comply with all the provisions of the
Respiratory Protection Standard. Non-compliance is not an option for
employers. Thus, there is no compliance reason to reduce the APF for
half masks.
As to whether assigning a protection factor of 10 to filtering
facepiece half masks will provide an economic incentive to use these
respirators, OSHA concludes that so long as a respirator achieves an
APF of 10, it doesn't matter what respirator an employer uses. Once
again, OSHA's data analyses, as well as consensus standards, show that
filtering facepieces can attain an APF of 10.
ANSI's updated APF of 5. Several commenters noted that the recent
draft of the ANSI Z88.2 respirator standard gave filtering facepieces
an APF of 5 (e.g., Exs. 9-8, 10-51, and 10-54; Tr. at 124-125 and 197-
201). For example, Bill Kojola of the AFL-CIO testified:
The AFL-CIO's position that filtering facepieces should be given
an APF of 5 is also provided by other organizations with considerable
expertise on respiratory protection. Indeed, the ANSI Z88.2 Committee,
charged with the responsibility for the American standard for respiratory
protection, has recently proposed an APF of 5 for filtering
facepiece respirators. We believe that OSHA should give serious
consideration to this ANSI position as well when it issues its final
rule. (Tr. at 124-125.)
OSHA considered the draft ANSI standard during this APF rulemaking.
However, this draft standard currently is under appeal, and has not
been designated by ANSI as a final standard (Ex. 17-9-10-2). Jill
Snyder, Standards Coordinator for the AIHA secretariat of the ANSI Z88
committee, addressed the status of the draft ANSI Z88.2 revised
respiratory protection standard in an e-mail sent to participants in
Roundtable 228 held at the 2004 AIHCE. This e-mail stated:
Until a standard is approved by ANSI, it is not an ANSI
standard. Therefore, we should not say things like `ANSI completed
drafting * * *' etc. It is actually the Accredited Standards
Committee (ASC) Z88 or Z88.2 that put together what is still the
DRAFT standard. We also have to make sure we call it a draft
standard, not a standard at this point. (Ex. 17-9-10-2.)
The method used by ANSI to determine the draft APFs also differs
from OSHA's approach, which used data analyses and expert opinion to
arrive at the final APF for half masks. James Johnson, representing the
ANSI Z88.2 subcommittee, stated that the subcommittee did not perform
an extensive quantitative analyses similar to OSHA's in determining the
draft APFs (Tr. at 357). In response to questions from Thomas Nelson,
ANSI subcommittee member George Macaluso confirmed that an overall
tabulation and review of available WPF data was not conducted by the
ANSI subcommittee in determining APFs (Tr. at 663-666).
With regard to the decision of the ANSI subcommittee, James Johnson
agreed that a subcommittee composed of other members may have reached a
different conclusion regarding the APF for filtering facepiece half
masks (Tr. at 354-355). He also stated:
There's nothing in the consensus process that says every part of
the standard has to have an absolute defendable, scientific,
technically traceable base. It doesn't exist. It's not there. We
have tremendous numbers of standards that are out there that the
professionals develop with the best knowledge and experience that
they have, and this is the process. (Tr. at 363.)
Summary and conclusions. In this section, OSHA considered the issue
of the appropriate APF for filtering facepieces. OSHA's data analyses
in the record support an APF of 10 for filtering facepiece respirators.
Moreover, a number of commenters supported the APF of 10. Some
commenters recommended a lower APF for filtering facepieces than
proposed based on the poor structural integrity of the mask, the
availability of additional models of respirator protection, poor
compliance with the respirator program requirements, difficulty
performing user seal checks, increased breathing resistance among
filtering facepieces approved under 42 CFR part 84, and the recent ANSI
draft APF for filtering facepieces. As discussed in the previous
sections, the evidence in the record with regard to these issues
justifies retaining in this final rulemaking the proposed APF of 10 for
filtering facepieces.
3. APF for Full Facepiece Air-Purifying Respirators
Introduction. In a 1976 report, Ed Hyatt of LANL developed an APF
table that included this respirator class (Ex. 2). In this report,
Hyatt used the results from quantitative fit testing to assess six
models of full facepiece negative pressure air-purifying respirators
equipped with HEPA filters. Five of these respirators achieved a
protection factor of at least 100 for 95% of the respirator users. The
sixth respirator attained this level of protection for 70% of the
users. Based on the results for the sixth respirator, Hyatt recommended
an APF of 50 for the respirator class as a whole.
The 1980 ANSI respirator standard listed an APF of 100 for full
facepiece air-purifying respirators with DFM filters (Ex. 7-3). ANSI
increased the APF for this respirator class from 50 to 100 because the
poorly performing respirator in Hyatt's study was no longer in
production. Using the 1976 LANL quantitative fit testing results, the
1980 ANSI standard increased this APF to a maximum of 1,000 when the
respirator used HEPA filters and respirator users received quantitative
fit testing (Ex. 7-3).
Based on Hyatt's 1976 data, the 1987 NIOSH RDL recommended that
this respirator class receive an APF of 50 when equipped with a HEPA
filter. However, the RDL gave these respirators an APF of 10 when using
DFM filters. NIOSH gave these respirators an APF of 10 when equipped
with DFM filters because testing that it conducted showed that the
filters had relatively low efficiency.
The 1992 ANSI respirator standard retained the 1980 ANSI standard's
APF of 100 for full facepiece air-purifying respirators, but required
that respirator users perform quantitative fit testing and achieve a
minimum fit factor of 1,000 prior to using the respirators. QNFTs were
necessary because no QLFTs could achieve a fit factor of 1,000. The
ANSI standard kept this APF because the ANSI committee found, as it did
in 1980, that no WPF or SWPF studies had been performed for this
respirator class.
The following table summarizes the previous APFs assigned to full
facepiece air-purifying respirators.
----------------------------------------------------------------------------------------------------------------
APFs
Fully facepiece air-purifying ------------------------------------------------------------------------------
respirators 1992 ANSI
LANL (1976) 1980 ANSI standard NIOSH RDL (1987) standard
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All respirators in the class..... 50 (with HEPA 10 (with QLFT)...... 10 (with DFM filter) 100
filter).
100 maximum (with 50 (with HEPA ...........
QNFT). filter).
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In the proposal, OSHA also discussed a WPF study that Colton,
Johnston, Mullins, and Rhoe (Ex. 1-64-14) conducted in a lead smelter.
The respirator used in this study was a 3M 7800 full facepiece air-
purifying respirator equipped with HEPA filters. The authors found a
5th percentile protection factor of 95 for the sample, but concluded
that the respirator only provided reliable protection at a protection
factor of 50. In addition, a LANL SWPF study by Skaggs, Loibl, Carter,
and Hyatt (Ex. 1-38-3) measured the protection afforded by the MSA
Ultra Twin respirator with HEPA filters. The authors reported fit
factors with geometric means ranging from 1,000 to 5,300. However, 23
of the 60 measurements reported were less than 1,000, seven were less
than 100, and three were less than 50. Based on a careful review of
these studies, OSHA proposed an APF of 50 for full facepiece air-
purifying respirators.
OSHA requested comment in question 7 of the proposal on
whether it should limit full facepiece negative pressure respirators to
an APF of 20 when N95 filters are used. The NIOSH certification tests
for 42 CFR part 84 filters are conducted using monodisperse aerosols of
the most penetrating particle size (0.3 [mu]m) delivered at a high flow
rate of 85 liters per minute. Also, the 42 CFR part 84 certification
standards allow up to 5% filter leakage with an N95 filter. If this level
of leakage were to occur in the workplace, an APF of 20 would be
appropriate for a full facepiece respirator using N95 filters. However,
as several commenters noted (Exs. 9-16, 9-22, 9-23, 9-37, 10-6, 10-17,
10-27, 10-59, and 10-60), workplace filter penetration is always much
less than filter penetration estimated from certification testing.
Kenneth Bobetich of MSA (Ex. 9-37) stated that while 5% leakage is the
worst case, such leakage does not occur in the workplace. Compared to
the aerosols used in certification testing, workplace aerosols are not
monodisperse, are many times larger, and are delivered through the
filters at a lower flow rate. In addition, the 3M Company (Ex. 9-16)
cited studies performed by Janssen (Exs. 9-16-1-3 and 9-16-1-4) that
compared the performance of N95 and P100 filters made by two
manufacturers and used during grinding operations in a steel plant.
Workplace performance of both filters was equivalent statistically, and
the study showed that N95 filter performance was adequate under these
conditions. Lisa Brosseau of the University of Minnesota (Ex. 10-59)
stated that it was entirely inappropriate for OSHA to consider a 5%
leakage effect for N95 filters because such leakage would only occur
when the aerosol is monodisperse and of a small size, conditions that
she said are unlikely to occur in most workplaces.
Bill Kojola of the AFL-CIO (Ex. 9-27), Pete Stafford of the
Building Construction Trades Department of the AFL-CIO (Ex. 9-29), and
Michael Watson of the International Brotherhood of Teamsters (Ex. 9-7)
supported limiting the APF for full facepieces to 20 when N95 filters
are used. Watson stated that if OSHA gave these respirators an APF
higher than 20, employees would likely be exposed to hazardous levels
of workplace contaminants. Kojola stated further that OSHA should take
into account both sources of leakage (filter and faceseal), and lower
the APF accordingly. However, neither Watson nor Kojola provided any
evidence to support these misgivings about the performance of these
respirators.
NIOSH (Ex. 9-13) recommended that OSHA consider the limitations of
the filter, but did not have any WPF or SWPF data on the performance of
full facepiece respirators certified under 42 CFR part 84 using N, R,
or P95 filters. NIOSH stated that because the filters are tested at the
most penetrating particle size, filter efficiency in the workplace
should exceed certification efficiency. However, NIOSH noted that some
workplace tasks, such as welding and grinding, may result in high
leakage rates through the N95 filter because the tasks produce fine or
ultra fine particles.
Loraine Krupa-Greshman of the American Chemistry Council (Ex. 10-
25) stated that OSHA could not justify using a simplistic, generalized
treatment of N95 filter efficiency to limit the APF to 20. She noted
that using N95 or N100 filters is a matter of professional judgment,
based on the type and concentration of the contaminant. Frank White of
ORC Worldwide (Ex. 10-27) stated that reducing the APF to 20 was
unnecessary because protection factors and filter performance need to
be considered separately as part of the respirator selection process.
Ted Steichen of the American Petroleum Institute (API) (Ex. 9-23)
mentioned that API believes that OSHA should further evaluate the data
before assigning, based on worst-case assumptions, an APF of 20 to
these respirators. Thomas O'Connor of the National Grain & Feed
Association (Ex. 10-13) commented that he was not aware of any
scientific information that refuted assigning an APF of 50 to full
facepiece respirators or justified lowering the APF for N95 filters to
20. He supported retaining the proposed APF of 50 for this class of
respirators. Sheldon Coleman of the Hanford Site Respiratory Protection
Committee (Ex. 10-40) stated that, based on fit testing data, an APF of
50 for these respirators already is conservative.
OSHA agrees with these commenters that full facepiece respirators
with N95 filters provide sufficient protection to maintain an APF of
50, and Table 1 of the final standard reflects this decision. Any
effect of filter penetration on respiratory protection is best
addressed during respirator selection, which also is the case for half
masks and other respirator classes using particulate filters. In rare
cases, when workplace exposures consist of a large percentage of
particles of the most penetrating size, this information must be taken
into account by the employer when selecting the appropriate class of
particulate filter for any respirator, not just for full facepieces.
Summary and conclusions. In the proposal, OSHA asked for any
additional studies of full facepiece air-purifying respirators, but
none was submitted. After carefully evaluating the original studies
reviewed in the proposal, the Agency is setting an APF of 50 for full
facepiece air-purifying respirators. The final APF agrees with the
conclusion of Colton, Johnston, Mullins, and Rhoe (Ex. 1-64-14) cited
earlier in this discussion that this class of respirators provides
reliable protection at an APF of 50. Importantly, an APF of 50
corresponds with the APF previously assigned to full facepiece air-
purifying respirators by OSHA in its substance-specific standards, and
by NIOSH in its 1987 RDL. Therefore, OSHA is assigning an APF of 50 to
full facepiece air-purifying respirators based on: the results of WPF
and SWPF studies (which used N95 filters at moderate to high
contaminant levels); The APFs given previously to this respirator class
by NIOSH and ANSI; comments in the record indicating that N95 filters
function effectively under the workplace exposure conditions in which
they are used; and years of experience showing that these respirators,
when equipped with an N95 filter, are safe when used in the manner
prescribed by OSHA's respiratory protection standards. However, as with
any respirator, if a full facepiece air-purifying respirator is
unsuitable for the exposure conditions, paragraph (d)(1) of OSHA's
Respiratory Protection Standard requires that employers select a
respirator that will protect employees from the exposure hazards.
4. APF for Powered Air-Purifying Respirators (PAPRs)
Half mask tight-fitting PAPRs. In the proposal, OSHA assigned an
APF of 50 to tight-fitting half mask PAPRs (68 FR 34098 and 34115)
based on the 1987 NIOSH RDL and the Z88.2-1992 ANSI respirator
standard. In arriving at a proposed APF of 50 for these respirators,
the Agency relied heavily on the WPF study conducted by Lenhart and
Campbell (Ex. 1-64-42), instead of the WPF study performed by Myers and
Peach (Ex. 1-64-46) and the SWPF studies of Skaggs et al. (Ex. 1-38-3)
and da Roza et al. (Ex. 1-64-94). In explaining its position, OSHA
stated:
[The Lenhart and Campbell] study was well controlled and
collected data under actual workplace conditions; these conditions
ensure that the results are reliable and represent the protection
employees likely would receive under conditions of normal respirator
use. The Agency did not consider the Myers and Peach WPF study * * *
for this purpose because of problems involving filter assembly
leakage and poor facepiece fit reported by the authors;
consequently, the abnormally high levels of silica measured inside
the mask would most likely underestimate the true protection
afforded by the respirator. The two SWPF studies * * * reported much
higher geometric mean protection factors than did the WPF study
performed by Lenhart and Campbell. However, OSHA believes that the
higher protection factors reported for these SWPF studies are
consistent with the proposed APF of 50 based on data obtained for
this respirator class in the Lenhart and Campbell WPF study because
SWPF studies typically report significantly higher protection
factors than WPF studies of the same respirator. (68 FR 34098.)
During this rulemaking, OSHA received no substantive comments or
other information regarding the proposed APF of 50 for these
respirators. Nevertheless, OSHA believes that the existing WPF and SWPF
studies on this class proved adequate support for OSHA's conclusion
that an APF of 50 is an appropriate level to predict the protection
capabilities of this class of respirators.
Full facepiece PAPRs and PAPRs with hoods or helmets. In the
proposal, OSHA assigned an APF of 1,000 to tight-fitting full facepiece
PAPRs (68 FR 34099). In support of the proposed APF, OSHA cited a WPF
study by Colton and Mullins that found a corrected 5th percentile
protection factor of 1,335 for these respirators. OSHA received no
substantive comments or other information regarding the proposed APF of
1,000 for these respirators. However, the ANSI Z88.2-1992 respirator
standard and the 2004 draft revision to the ANSI standard both assign
an APF of 1,000 to this respirator class. Based on its review of these
consensus standards and the existing WPF research literature (see Exs.
1-64-12 and 1-64-40), and SWPF research studies (Ex. 3-4), OSHA
concludes that this respirator class warrants an APF of 1,000.
In proposing an APF of 1,000 for PAPRs with helmets or hoods, the
Agency stated in footnote 4 of proposed Table 1 that "only helmet/hood
respirators that ensure the maintenance of a positive pressure inside
the facepiece during use, consistent with performance at a level of
protection of 1,000 or greater, receive an APF of 1,000" and that
"[a]ll other helmet/hood respirators are treated as loose-fitting
facepiece respirators and receive an APF of 25." (See 68 FR 34115.)
OSHA proposed this condition because available WPF and SWPF studies
found that some of these hood/helmet respirators achieved protection
factors well below 1,000 (Exs. 3-4 and 3-5). Under the proposed
condition, the burden of conducting any testing likely would fall on
respirator manufacturers, but the employer would be responsible for
selecting a properly tested respirator.
According to James Johnson of LLNL, simple and effective equipment
and procedures are available for detecting leaks in these respirators.
In this regard, Johnson noted that LLNL developed equipment that
monitors and records positive pressure in these respirators using a
commercially available device. As he stated at the hearing:
[T]his is the one we chose, a data logging micro manometer, the
TSI-DP Calc, with a range of -5 to +15 inches of water gauge, and
data recording intervals of one second and longer were chosen. * * *
We plan on using this technique periodically to monitor actual high-
contamination work activities to assure this PAPR maintains a
positive pressure. (Ex. 16-9-1.)
A number of commenters provided additional support for using
positive pressure inside the facepiece as the criterion for protection.
For example, Rick Givens of the Atlanta, GA Utilities Department stated
that "the maintenance of positive pressure is an appropriate method
for distinguishing high-performing hood/helmet respirators from
others" (Ex. 10-2), while Sheldon Coleman of the Hanford, Washington
DOE site asserted:
In the last three years, our program has used approximately
10,000 PAPR hoods. We have conducted some limited fit testing using
particulate fit testers (although the hood manufacturer does not
recommend using a particulate tester due to the extensive dead space
in the hood). All of our information suggests that an APF of 1,000
is appropriate for a PAPR hood that maintains positive pressure
inside of the hood. (Ex. 10-40.)
Several commenters took exception to the positive pressure
criterion. Craig Colton of 3M stated that "3M disagrees with OSHA's
proposed requirement that hoods and helmets demonstrate that they
maintain positive pressure at all times of use to receive an APF of
1,000" (Tr. at 390). In this regard, Colton argued that the recent
study conducted on PAPRs with hoods/helmets by ORC and LLNL showed that
every respirator tested in the study "had two or more brief negative
pressure spikes within the respiratory inlet covering. Under the
current proposal, all of these respirators, except the poorest
performing supplied-air respirator would have received an APF of 25,
even though the 5th percentile SWPFs found in the study ranged from
86,000 to 250,000" (Tr. at 391). Colton then added, "This study
indicates that pressure within the respiratory inlet covering is only
one of a complex set of factors that determine the protection provided
by PAPRs and supplied-air respirators, and should not be considered by
itself" (Tr. at 391). John P. Farris of Safe Bridge Consultants echoed
this concern (Exs. 9-11 and 10-32).
Other comments focused either on the need for a protocol to
determine if the respirators could perform at an APF level of 1,000, or
on design characteristics that would permit respirator users to select
appropriate respirators. In advocating the testing approach, Stephan
Graham of the U.S. Army Center for Health Promotion and Preventative
Medicine noted that respirators that have high APFs should receive
credit for their design and performance. Graham recommended that
manufacturers test their hooded and helmeted respirators, and set the
maximum APF (to a maximum of 1,000) based on the results (Ex. 9-42-1).
The 3M Company stated that if OSHA retains a testing requirement in the
final rule, it must specify the testing conditions. The 3M Company
recommended testing at a work rate of 40 liters per minute, ensuring
that pressure inside the hood or helmet is maintained at a minimum
level of one atmosphere at this work rate, measuring this pressure at
the flow rate recommended by the manufacturer, and maintaining the
maximum static pressure inside the hood or helmet at 38 mm of water
pressure (Ex. 18-7). Similarly, Jay Parker of the Bullard Co. stated
that "without oversight and guidance, testing performed may not
achieve such goals. This may lead to the use of respirators and an APF
of 1,000 that actually should not be used at that level because the
testing performed was not really capable of ensuring that level of
performance" (Tr. at 492).
ORC Worldwide stated that "the approach proposed by OSHA would
hold hood/helmet or loose-fitting facepiece PAPRs and SARs to a higher
standard than that required of other respirator classes, based simply
on the results of one model" (Ex. 10-27), a point made as well by
Alice E. Till of the Pharmaceutical Research and Manufacturers
Association (PhRMA) (Ex. 9-24). Nevertheless, ORC concluded that,
"[s]hould OSHA retain this requirement, the final rule should clearly
specify acceptable testing criteria to which respirator manufacturers
must conform" (Ex. 10-27). PhRMA believed that OSHA should consider
the proposed APF table to be an interim step in a transition toward the
development of a certification protocol by NIOSH that provides APFs for
each respirator model (Ex. 9-24). Thomas Nelson of NIHS, Inc. agreed,
stating, "Specific test conditions and performance criteria must be
identified" (Ex. 10-17).
Respirator models should not be assigned to the higher APF level
following promulgation of the proposed APF rule unless the
respirator manufacturer provides evidence that testing of that model
demonstrates performance at the higher APF level. A standard test
protocol is needed to assure reliable and reproducible results when
determining if a hood/helmet PAPR * * * can consistently achieve a
protection factor of 1000. NIOSH will assist in developing this
protocol. With implementation of new NIOSH certification criteria,
every respirator model could be evaluated using this protocol as a
condition of certification to assure overall performance consistent
with the established APF. Thus, NIOSH will assure that approved
respirators are capable of providing this assigned level of
protection so that employers have appropriate guidance and APF
values when selecting respirators for their workers. (Ex. 16-4.)
Proponents of using design criteria, instead of testing, to assess
the protection afforded by these respirators recommended that poorer
performing respirators should be identifiable by either their
appearance or technical specifications. For example, John Ferris of
Safe Bridge Consultants, stated:
In my experience, the most important factor in achieving
workplace protection factors of 1,000 or greater with these devices
is the ability to tuck the inner bib (or shroud) into the outer work
garment with the outer shroud placed over the shoulders on the
outside of the garment. I support the use of a 1000-fold APF for
helmet hood PAPRs without the footnote. (Ex. 9-11.)
Robert Barr of Alcoa noted that design flaws need to be identified,
stating, "For example, flip-front types could be designated 25; and
helmets with shrouds at 1000" (Exs. 9-26 and 10-31). PhRMA, ORC, and
the American Chemistry Council argued that OSHA should base the APFs
for these respirators on design and construction characteristics that
would "enable a more exacting selection process, and * * * would be
conducive to eventually assigning protection factors based on
individual model performance" (Exs. 9-24 and 10-27). However, Jay
Parker of the Bullard Co. noted that the latest ANSI Z88.2 subcommittee
"was unable to agree on the design characteristics of a hood or helmet
that would lead to a performance level equivalent to an APF of 25"
(Tr. at 480). Continuing, Jay Parker stated:
I don't see that we will ever be able to define the performance
of a respirator by its design. We don't want to stifle innovation.
We want to be able to allow respirator manufacturers to develop new
hoods and helmets. If OSHA comes up with a definition that limits a
hood or helmet to a certain design, then that would limit the
manufacturer's ability to innovate with new designs. (Tr. at 480.)
After reviewing the comments on proposed footnote 4, OSHA concludes
that: no single parameter (e.g., positive pressure inside the
facepiece) will identify respirators that consistently perform at a
high APF level; no agreement exists on how to determine APFs for these
respirators based on design characteristics alone; no uniform testing
criteria are available to use in determining APFs for these
respirators; and ample evidence demonstrates that WPF or SWPF studies
conducted under a variety of conditions reliably determine reliable and
safe protection factors for these respirators. Therefore, OSHA is
revising footnote 4 to Table 1 in the final standard to read as
follows:
The employer must have evidence provided by the respirator
manufacturer that testing of these respirators demonstrates
performance at a level of protection of 1,000 or greater to receive
an APF of 1,000. This level of performance can best be demonstrated
by performing a WPF or SWPF study or equivalent testing. Absent such
testing, all other PAPRs and SARs with helmets/hoods are to be
treated as loose-fitting facepiece respirators, and receive an APF
of 25.
The Agency is setting an APF of 1,000 for tight-fitting facepiece
PAPRs with hoods and helmets when the manufacturers of these
respirators conduct testing that demonstrates that the respirators
provide a level of protection of at least 1,000(e.g., demonstrating
WPFs of at least 10,000 or greater divided by a safety factor of 10, or
lower fifth percentile SWPFs of at least 25,000 divided by a safety
factor of 25). Based on its review of the record regarding these
respirators, the Agency believes that tight-fitting facepiece PAPRs
with hoods and helmets tested in a manner that is consistent with the
SWPF testing performed previously under the ORC-LLNL study of
respirators in this class (Ex. 3-4-1) will provide the required level
of protection for employees who use these respirators.
While proposed footnote 4 emphasized that respirator manufacturers
have responsibility for testing these respirators, it did not address
who is responsible for selecting properly tested respirators.
Consistent with Section 5 of the OSH Act (29 U.S.C. 654), which places
the responsibility for employee protection on employers, footnote 4 in
the final rule now clearly places the responsibility for proper
respirator selection on employers. Accordingly, employers may use a
respirator at an APF of 1,000 only when they have appropriate test
results provided by the respirator manufacturer demonstrating that the
respirator performs at a protection level of 1,000 or greater.
Evidence in the rulemaking record indicates that the technology
exists to measure any leakage into the facepiece from the ambient
atmosphere that could lessen the protection afforded by a PAPR or SAR
with a helmet or hood (Ex. 16-9-1). This evidence also shows that small
amounts of leakage measured by this technology during testing did not
reduce the performance of the respirator below a level that was
consistent with an APF of at least 1,000 (Exs. 3-4-1, 1-38-3, 1-64-12,
and 1-64-40) Based on this evidence, OSHA believes that it is important
for respirator manufacturers to determine, using available technology,
that leakage into a respirator does not compromise the respirator's
capability to maintain a level of performance throughout testing that
is consistent with an APF of at least 1,000. Therefore, the Agency
removed from footnote 4 in the final rule the language in proposed
footnote 4 stating that "only helmet/hood respirators that ensure the
maintenance of positive pressure inside the respirator during use * * *
receive an APF of 1000."
Loose-fitting facepiece PAPRs with hoods or helmets. OSHA proposed
an APF of 25 for loose-fitting PAPRs with hoods or helmets based on WPF
studies described in the proposal (68 FR 34100), the NIOSH RDL, and the
Z88.2-1992 ANSI respirator standard. In supporting the proposed APF,
ISEA commented that "as the reports of many WPF studies have shown,
the performance of loose-fitting PAPRs with loose-fitting facepieces
warrants a lower APF than for loose-fitting hoods and helmets" (Ex. 9-
24). Additional support came from Warren Myers, OSHA's expert witness
at the rulemaking hearing, who stated:
Our summary conclusion was that PAPRs were incorrectly
considered as positive pressure devices by the respirator community
and that a minimum certification air flow of 170 liters a minute, at
least for the loose-fitting class of devices, does not necessarily
provide a positive pressure operational characteristic with the
respirator. And then finally, that the assigned protection factor
for these devices with those types of air flows would be 25. (Tr. at
69.)
The WPF studies previously cited (68 FR 34100) demonstrate that
OSHA based the proposed APF on valid data that were substantiated by
the Myers study. OSHA concludes that an APF of 25 is appropriate for
loose-fitting facepiece PAPRs with hoods or helmets, and therefore is
retaining this APF for this respirator class in the final rule. No
adverse comments regarding the proposed APF were submitted.
5. APFs for Supplied-Air Respirators (SARs)
Half mask SARs. The Agency based its proposed APF of 10 for this
respirator class on the analogous performance between these respirators
and negative pressure half mask air-purifying respirators tested in WPF
and SWPF studies (68 FR 34100). Furthermore, the Agency proposed to
give half mask SARs that function in continuous flow or pressure-demand
modes an APF of 50, consistent with the analogous performance between
these respirators and half mask PAPRs operated in a continuous flow
mode during WPF and SWPF studies. Additional support for the proposed
APFs came from the Z88.2-1992 ANSI respirator standard that assigned an
APF of 10 to half mask airline SARs operated in the demand mode, and an
APF of 50 to these respirators when operated in the continuous flow or
pressure-demand modes. The 1987 NIOSH RDL also gave half mask demand
SARs an APF of 10, but recommended an APF of 1,000 for these
respirators when functioning in the pressure-demand or other positive-
pressure modes.
OSHA received no comments or other information during this
rulemaking regarding these proposed APFs. However, the Agency is
confident that the available WPF and SWPF studies for half mask air-
purifying respirators cited in the proposal provide sufficient data to
retain an APF of 10 for half mask SARs when operated in the demand
mode, and an APF of 50 for these respirators when operated in the
continuous flow or pressure-demand modes. Therefore, OSHA is retaining
these APFs in Table 1 of the final rule.
Full facepiece SARs. OSHA stated in the proposal that "[n]o WPF or
SWPF studies were available involving tight-fitting full facepiece SARs
operated in the demand mode. Therefore, in the absence of any such
quantitative data, the Agency assigned this respirator class an APF of
50" (68 FR 34102). OSHA based the proposed APF on the analogous
operational characteristics of these respirators and negative pressure
full facepiece air-purifying respirators tested under WPF conditions in
the demand mode. Also, the proposed APF is the same as the APF
recommended for this respirator class by the 1987 NIOSH RDL.
The Agency proposed an APF of 1,000 for full facepiece SARs
operated in continuous flow, pressure-demand, or other positive-
pressure mode (68 FR 34102). It based the proposed APF on a SWPF study
(Ex. 1-38-3) in which the results for these respirators showed
geometric mean protection factors ranging from 8,500 to 20,000. Further
justification for the proposed APF came from the similarity in
operational characteristics between these respirators and tight-fitting
full facepiece continuous flow PAPRs, which had a proposed APF of
1,000. The proposed APF for these respirators also was consistent with
the APFs of 1,000 assigned to them under the Z.88.2-1992 ANSI
respirator standard, and was substantially lower than the APF of 2,000
recommended for these respirators by the 1987 NIOSH RDL.
OSHA received no comments on full facepiece SARs operated in a
demand, pressure-demand, or other positive-pressure mode. The Agency
believes that the evidence in the proposal is sufficient to support an
APF of 50 for these respirators when operated in the demand mode, and
an APF of 1,000 when the respirators function in a pressure-demand or
other positive-pressure mode, and has included these APFs in the final
standard.
SARs with hoods or helmets. Based on a number of WPF studies, OSHA
proposed an APF of 1,000 for continuous flow SARs with hoods or
helmets, contingent on the manufacturers' demonstration that the
respirators meet the criteria specified in Table 1 of the proposed
standard (68 FR 34103). In responding to the proposed APF, Paul Schulte
of NIOSH noted that an APF of 1,000 is appropriate for these
respirators only when the manufacturer demonstrates that the models
performed at this level (Ex. 9-13). ORC Worldwide stated that only SWPF
data would give employers the assurance that the SAR offers the
necessary protection for their workers (Ex. 10-27). ISEA recommended
that further testing be performed before assigning an APF of 1,000 for
continuous flow SARs with hoods and helmets (Ex. 9-22). MSA concluded
that an APF of 1,000 is appropriate (Ex. 16-10) because, it asserted,
every credible WPF study demonstrates that continuous flow SARs with
hoods and helmets perform at an APF of 1,000.
These commenters generally agree that continuous flow SARs with
hoods or helmets should be assigned an APF of 1,000 only after
manufacturers demonstrate through appropriate WPF or SWPF studies that
the respirators are capable of performing at an APF of 1000. Therefore,
based on the evidence cited in the proposal, the comments from ORC
Worldwide, NIOSH, and ISEA, and the absence of any new studies or
evidence submitted in response to the proposal, OSHA is assigning these
respirators an APF of 1,000 in the final rule only when the employer
can provide evidence from the respirator manufacturers that
demonstrates the respirators perform at that level; absent such
testing, these respirators must receive an APF of 25.
Loose-fitting facepiece SARs. OSHA proposed an APF of 25 for this
class of respirators based on analogous performance between these
respirators and loose-fitting facepiece PAPRs (68 FR 34104). Additional
support cited in the proposal included data from NIOSH showing that the
two types of respirators (i.e., loose-fitting facepiece SARs and PAPRs)
have the same minimum airflow rates when evaluated under 42 CFR part
84. The proposed APF also is consistent with the APF specified for
respirators in the 1987 NIOSH RDL and the Z88.2-1992 ANSI respirator
standard.
Commenters agreed with OSHA's proposed APF of 25 (Exs. 9-22 and 10-
39; Tr. at 75 and 546). For example, Warren Myers stated, "I believe
it is reasonable for OSHA to use analogous operational characteristics
between PAPRs and SARs equipped with loose-fitting hoods or helmets to
set the APF for the SARs devices at 25" (Tr. at 75). ISEA noted that
WPF studies conducted on loose-fitting facepieces justify an APF of 25
for these respirators (Ex. 9-22). Based on these comments, the
analogous performance with loose-fitting PAPRS, NIOSH certification
testing at the same minimum flow rates, and the APFs given these
respirators in the 1987 NIOSH RDL and the ANSI Z88.2-1992 respirator
standard, OSHA has concluded that an APF of 25 is appropriate for this
respirator class. Therefore, the final rule will list an APF of 25 for
SARs with loose-fitting facepieces.
6. APF for Self-Contained Breathing Apparatuses (SCBAs)
Ed Hyatt, in 1976, assigned a protection factor of 50 to a full
facepiece SCBA operated in the demand mode, the same protection factor
he assigned to full facepiece SARs used in this mode. Based on results
from a panel of 31 respirator users tested at LANL, he gave full
facepiece SCBAs used in the pressure demand mode an APF of 10,000+ (Ex.
2). The 1980 ANSI respirator standard listed half mask and full
facepiece SCBAs operated in the demand mode with APFs of 10 and 100,
respectively, when qualitatively fit tested. The APFs for half mask or
full facepiece SCBAs functioning in the demand mode were the protection
factors obtained during quantitative fit testing, with this APF limited
to the sub-IDLH value. Full facepiece SCBAs used in the pressure-demand
mode received an APF of 10,000+. The 1987 NIOSH RDL recommended that half
mask and full facepiece SCBAs operated in the demand mode receive APFs of
10 and 50, respectively, and that the APF for full facepiece SCBAs operated
in the pressure-demand or other positive pressure mode be 10,000.
The Z88.2 subcommittee responsible for the 1992 ANSI respirator
standard could not reach a consensus on an APF for full facepiece
pressure-demand SCBAs. Available WPF and SWPF studies reported that, in
some cases, the respirators did not achieve an APF of 10,000 (Ex. 1-
50). Nevertheless, the subcommittee found that a maximum APF of 10,000
was appropriate when employers use the respirators for emergency-
planning purposes and could estimate levels of hazardous substances in
the workplace.
Two respirators equipped with hoods, Draeger's Air Boss Guardian
and Survivair's Puma, have operational characteristics similar to
SCBAs. The facepiece of the Draeger respirator consists of a hood with
an inner nose cup and a tight-fitting seal at the neck, and an air
cylinder that supplies breathing air to the facepiece. NIOSH reviewed
this respirator in accordance with its 42 CFR part 84 certification
requirements, and in January 2001 certified the respirator as a tight-
fitting full facepiece demand SCBA when equipped with a cylinder having
a 30-minute service life. NIOSH also approved the respirator for use in
entering and escaping from hazardous atmospheres. In a May 16, 2001
letter to OSHA's Directorate of Enforcement Programs (Ex. 7-1), Richard
Metzler of NIOSH justified the classification of the Draeger respirator
as an SCBA on the basis that the neck seal, which is integral to the
facepiece, forms a gas-tight or dust-tight fit with the face consistent
with the definition of a tight-fitting facepiece specified by 42 CFR
84.2(k). This letter also noted that the fit testing procedures used
for full facepiece demand SCBAs apply to the Draeger SCBA, and that, as
a full facepiece demand SCBA, NIOSH recommended that the respirator
receive an APF of 50 in accordance with its 1987 RDL.
NIOSH subsequently certified the Survivair Puma respirator, which
has a tight-fitting hood supplied by an air cylinder, as a pressure-
demand SCBA with a tight-fitting facepiece. As part of the 42 CFR part
84 certification process, NIOSH specified that the fit testing
requirement for tight-fitting SCBAs would apply to this respirator.
However, Steve Weinstein of Survivair (Ex. 7-2) stated that the hood
totally encapsulates the respirator user's hair, making quantitative
fit testing (e.g., with a Portacount) impossible. In such cases, the
fit testing instrument treats dander and other material shed by the
hair as particulates originating from outside the respirator, causing
the fit factor to be artificially low. Nevertheless, qualitative fit
testing with the hood is possible because Survivair provides an adapter
and P100 filters for this purpose. Such fit testing meets the fit-
testing requirements for tight-fitting SCBAs specified in paragraph
(f)(8) of OSHA's Respiratory Protection Standard.
The table below provides a summary of APFs given to the half mask
and full facepiece SCBAs by different groups.
----------------------------------------------------------------------------------------------------------------
APFs
SCBAs -------------------------------------------------------------- 1992 ANSI
LANL (1976) 1980 ANSI standard NIOSH RDL (1987) standard
----------------------------------------------------------------------------------------------------------------
Tight-fitting half mask........ 10 (demand)...... 10 (demand; with QLFT) 10 (demand)......
Same as QNFT factor
(demand; sub-IDLH
value max.).
Tight-fitting Full facepiece... 50 (demand)...... 100 (demand; with 50 (demand)......
QLFT) Same as QNFT
factor (demand; sub-
IDLH value max.).
Tight-fitting Full facepiece... 10,000 (pressure 10,000+ (pressure 10,000 (pressure 10,000 maximum
demand). demand). demand). (emergency
planning
purposes only).
----------------------------------------------------------------------------------------------------------------
OSHA received no new WPF or SWPF studies for tight-fitting half
mask SCBAs and tight-fitting full facepiece SCBAs operated in the
demand mode in response to the proposal. In the only WPF study
conducted on full facepiece positive-pressure SCBAs, Campbell, Noonan,
Merinar, and Stobbe of NIOSH assessed the performance of two different
models of full facepiece pressure-demand SCBAs that met the NFPA 1981
air-flow requirements for respirators used by firefighters (Ex. 1-64-
7). While the authors could not determine protection factors for these
respirators because contaminant levels measured inside the facepiece
were too low, pressure measurements taken inside the facepiece proved
more useful. These measurements showed that four of the 57 test
subjects (i.e., firefighters) experienced one or more negative pressure
incursions inside the facepiece while performing firefighting tasks.
After analyzing the data for these firefighters using two different
methods, the authors estimated that the overall protection factor
exceeded 10,000.
In the first of two SWPF studies performed on full facepiece SCBAs
used in the pressure-demand mode, McGee and Oestenstad determined the
protection afforded to members of a respirator test panel who used the
Biopack 60 closed-circuit SCBA (Ex. 1-64-86). Three members of the
panel had protection factors of 4,889, 7,038, and 18,900, with the
remaining members having protection factors over 20,000. In the second
study, Johnson, da Roza, and McCormack of LLNL (Ex. 1-64-98) tested the
Survivair Mark 2 SCBA that met NFPA 1981 air-flow requirements. During
testing, a panel of 27 test subjects exercised on a treadmill at 80% of
their cardiac reserve capacity. Although the authors found negative
pressure incursions inside the facepiece at high work rates, they
concluded that the respirator "provided [a minimum] average fit factor
of 10,000 [for any single subject], with no single subject having a fit
factor less than 5,000 at a high work rate." The tables below
summarize the results of the WPF and SWPF studies performed on full
facepiece pressure-demand SCBAs.
----------------------------------------------------------------------------------------------------------------
WPF studies for tight-fitting full Geometric
facepiece pressure demand SCBAs (by name Sample size Geometric standard 5th percentile WPF
of authors and model of respirator tested) mean deviation
----------------------------------------------------------------------------------------------------------------
Campbell et al. (Ex. 1-64-7) Unspecified 57 ........... ........... >10,000 (estimated).
model (with NFPA-compliant airflow).
----------------------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------------------
Geometric 5th
SWPF studies for ight-fitting full facepiece pressure demand Sample size Geometric standard percentile
SCBAs (by name of authors & mode of respirator tested) mean deviation WPF
----------------------------------------------------------------------------------------------------------------
McGee and Oestenstad (Ex. 1-64-86) Biopack 60 (closed 23 >20,000 ........... ...........
circuit)...................................................
Johnson et al. (Ex. 1-64-98) Survivair mark 2 with NFPA- 27 29,000 1.63 ...........
compliant airflow).........................................
----------------------------------------------------------------------------------------------------------------
Janice Bradley (Ex. 9-22) of the International Safety Equipment
Association and Kenneth Bobetich of the MSA Company (Ex. 9-37) both
stated that footnote 5 in the proposed OSHA APF Table 1 was not
necessary because most SCBA models now meet the increased air-flow
requirements in the NFPA 1981 standard. They further noted that the
study that served as the basis of the footnote was more than 15 years
old, and that OSHA should remove the footnote. They recommended that
the APF should be 10,000 for pressure-demand SCBAs that meet the air-
flow requirements of NFPA 1981. Janice Bradley (Tr. at 531) cited the
WPF study NIOSH performed with firefighters (Ex. 1-64-7) as supporting
the conclusion that SCBAs meeting the NFPR 1981 requirements would
provide APFs of 10,000.
Summary and conclusions. OSHA is setting APFs of 10 and 50,
respectively, for tight-fitting half mask SCBAs and tight-fitting full
facepiece SCBAs operated in the demand mode. In the absence of any new
WPF and SWPF studies on these respirators, the Agency is basing the
final APFs on analogous operational characteristics between these
respirators and half mask facepiece and full facepiece air-purifying
respirators, that have APF values of 10 and 50, respectively. In
addition, the final APFs are consistent with the APFs recommended by
the 1987 NIOSH RDL for these respirators. (Note that the 1992 ANSI
standard did not assign APFs for these respirator classes.)
For tight-fitting full facepiece SCBAs used in the pressure-demand
or other positive pressure modes, OSHA is setting an APF of 10,000 in
the final standard, which is consistent with the 1987 NIOSH RDL and the
1992 ANSI respirator standard. Empirical support for the final APF
comes from the WPF study conducted by Campbell, Noonan, Merinar, and
Stobbe (Ex. 1-64-7). This study showed that protection factors for
these respirators, when operating at NFPA-compliant air flows, far
exceed 10,000. While four respirator wearers experienced momentary
negative-pressure spikes inside their facepieces, which indicates
possible leakage into the facepiece under some workplace conditions,
these spikes did not impair overall respirator performance. The Agency
concludes that these study results justify an unrestricted APF of
10,000 for tight-fitting full facepiece SCBAs.
For the class of respirators designated as pressure-demand SCBAs
with tight-fitting hoods or helmets, including the Survivair Puma, OSHA
is setting an APF of 10,000. The basis for this final APF is the
analogous operational characteristics between these respirators and
tight-fitting full facepiece pressure-demand SCBAs.
D. Definition of Maximum Use Concentration
Employers use MUCs to select appropriate respirators, especially
for use against organic vapors and gases. MUCs specify the maximum
atmospheric concentration that an employee can experience while wearing
a specific respirator or class of respirators. MUCs are a function of
the APF determined for a respirator (or class of respirators), and the
exposure limit of the hazardous substance in the workplace.
1. Introduction
Ed Hyatt, in the 1976 LASL report on respiratory protection factors
(Ex. 2, Docket H049), recounted the early history of MUCs, starting
with the MUC recommendations of the joint AIHA-ACGIH committee in 1961.
This committee recommended that, for highly toxic compounds, full
facepiece respirators with HEPA filters use a maximum limit of 100
times the TLV. Hyatt noted that Dr. Letts in 1961 in the United
Kingdom, recommended that half mask dust respirators provided effective
protection against airborne contaminant levels no greater than 10 times
the TLV.
In 1974, NIOSH and OSHA started the Standards Completion Program to
develop standards for substances with existing PELs. As part of this
process, the initial respirator decision logic was developed and the
concept of MUCs began to be used. NIOSH Criteria Documents also
recommended MUCs for different types of respirators. The information
for these MUCs were obtained from various sources, including NIOSH
Current Intelligence Bulletins and recognized industrial hygiene
references. NIOSH later published this information in its Pocket Guide
to Chemical Hazards. Other source documents for MUC definitions and
regulations include the 1987 NIOSH RDL, and the ANSI Z88.2-1980 and
ANSI Z88.2-1992 respiratory protection standards.
OSHA's 1994 proposed Respiratory Protection Standard contained the
following definition of MUC:
Maximum use concentration (MUC) means the maximum concentration
of an air contaminant in which a particular respirator can be used,
based on the respirator's assigned protection factor. The MUC cannot
exceed the use limitations specified on the NIOSH approval label for
the cartridge, canister, or filter. The MUC can be determined by
multiplying the assigned protection factor for the respirator by the
permissible exposure limit for the air contaminant for which the
respirator will be used. (59 FR 58884.)
Several commenters to this 1994 proposal recommended alternatives
to this definition. Reynolds Metal Company recommended defining MUC as
"the maximum concentration of an air contaminant in which a particular
respirator can be used, based on the respirator's assigned protection
factor" (Ex. 1-54-222). The American Petroleum Institute (API) noted
NIOSH developed the term "MUC," and that, to avoid confusion, OSHA
should not use the term (Ex. 1-54-330). API proposed using the term
"assigned use concentration" to replace MUC. API defined "assigned
use concentration" as "the maximum concentration of an air
contaminant in which a particular respirator can be used, based on the
respirator's assigned protection factor" (Ex. 1-54-330). However, when
the Agency published the final Respiratory Protection Standard in 1998,
it reserved the definition of MUC in paragraph (b), and the MUC requirements
in paragraph (d)(3)(i)(B), for future rulemaking because it reserved the APF
provisions of the respirator selection section of the standard (i.e.,
MUCs could not be determined without knowing the APF values).
In the June 6, 2003 proposal, OSHA defined MUC as follows:
Maximum use concentration (MUC) means the maximum atmospheric
concentration of a hazardous substance from which an employee can be
expected to be protected when wearing a respirator, and is
determined by the assigned protection factor of the respirator or
class of respirators and the exposure limit of the hazardous
substance. The MUC usually can be determined mathematically by
multiplying the assigned protection factor specified for a
respirator by the permissible exposure limit, short-term exposure
limit, ceiling limit, peak limit, or any other exposure limit used
for the hazardous substance. (68 FR 34036.)
Under this definition, MUC represents the maximum atmospheric
concentration of a hazardous substance against which a specific
respirator or class of respirators with a known APF can protect
employees who use these respirators. Accordingly, MUCs are a function
of the APF determined for a respirator (or class of respirators) and
the exposure limit of the hazardous substance in the workplace.
The last sentence in the definition describes the MUC in terms of a
mathematical calculation, i.e., that employers can "usually"
determine the MUC by multiplying the APF for the respirator by the
exposure limit used for the hazardous substance.\10\ The last sentence
of the proposed definition also specifies the exposure limits as
"permissible exposure limit (PEL), short-term exposure limit (STEL),
ceiling limit (CL), peak limit, or any other exposure limit used for
the hazardous substance." Although OSHA received no comments on the
proposed definition, it nevertheless is making several minor revisions
to the definition in the final rule. First, the Agency is removing the
term "usually" from the definition because multiplying the assigned
protection factor by the exposure limit for a hazardous substance is
the currently accepted method used by safety and health professionals
for calculating MUCs. Absent any other accepted method, the term
"usually" is confusing and unnecessary.
---------------------------------------------------------------------------
\10\ For example, when the hazardous substance is lead (with a
PEL of 50 [mu]g/m\3\), and the respirator used by employees has an
APF of 10, then the calculated MUC is 500 [mu]g/m\3\ or 0.5 mg/m\3\
(i.e., 50 [mu]g/m\3\ x 10).
---------------------------------------------------------------------------
The second revision to the proposed MUC definition involves the
last part of the second sentence, which required employers to consider
an "exposure limit" when determining an MUC. OSHA is making two
changes to this proposed language to make clear its intent regarding
the information employers need to consider when making this
calculation. First, OSHA is clarifying the language to require
employers to calculate an MUC using an OSHA exposure limit in those
instances where one exists. OSHA was concerned that employers could
have misinterpreted the language in the proposed MUC definition as
meaning that they could use any available exposure limit for
calculating an MUC (and, by implication, for protecting employees from
hazardous airborne contaminants). This revision emphasizes the priority
that OSHA exposure limits have in regulating hazardous airborne
contaminants.
Second, OSHA is changing the language to make clear the information
employers need to consider to determine an MUC in the absence of an
OSHA exposure limit. The Agency revised the language to require
employers to use relevant available information and informed
professional judgment when determining an MUC when no OSHA exposure
limit exists. This language more clearly states OSHA's intent that
employers can utilize a wide range of available information in
calculating an MUC when OSHA has not yet promulgated an exposure limit
for a hazardous airborne contaminant. While not required, some
employers may choose to conduct individualized risk assessments of
hazards. Others may consult information from manufacturers or other
published exposure limits (e.g., the NIOSH RELs or the AIHA WEELs) for
making MUC determinations. However, whatever approach employers choose
to take, the MUC must provide adequate protection for their employees.
OSHA believes this approach provides employers with greater flexibility
than the proposed MUC definition while still maintaining employee
protection.
The Agency also broadened the language in this second sentence by
requiring employers to "take the best available information into
account" when determining an MUC in the absence of an OSHA exposure
limit. This language is consistent with the guidance that the Agency
provided to employers in the preamble to the Respiratory Protection
Standard for determining APFs in the absence of a final APF standard
(see, e.g., 63 FR 1203). OSHA believes this language gives employers
maximum flexibility to develop MUCs that protect their employees from
hazardous airborne contaminants, including the use of other exposure
limits when appropriate.
In the proposal to this final rule, OSHA requested comments on the
development of the MUC for substances with no OSHA PEL, limiting
factors such as eye irritation, LELs and IDLHs, and mixtures of
substances (68 FR 34112). OSHA received numerous comments on these
issues, as well as on hazard ratios, an issue raised by several
commenters. These issues are discussed in the following sections.
2. MUCs for Substances With No OSHA PEL or Other Limiting Factors
OSHA received many comments on this issue. Some commenters believed
that in the absence of a PEL it is appropriate for the Agency to
require calculation of MUCs based on other information (Exs. 10-54, 9-
27, and 10-3). Other commenters supported using any occupational
exposure limit for this purpose, but some of these commenters specified
that no other limiting factors should be used (Exs. 9-26, 9-42, 10-27).
Others specified that additional limiting factors were needed (Exs. 9-
13, 9-15, 9-29, 10-6, and 10-60). Several commenters recommended using
only the OSHA PELs with limiting factors (Ex. 10-17, 10-25, and 9-16)
or without limiting factors (Exs. 9-22 and 9-23). A few commenters
addressed limiting factors only, either supporting specific factors
(Exs. 9-12 and 10-1) or stating that no limiting factors were needed
when determining MUCs (Ex. 9-37). These comments are discussed in the
following paragraphs.
W.M. Parris of Alabama Power (Ex. 9-15) proposed the following
generic definition of MUC that would include all possible MUCs:
Maximum use concentration (MUC) means the maximum atmospheric
concentration of a hazardous substance from which an employee can be
expected to be protected when wearing a respirator. The MUC will be
the lowest of the following: (1) IDLH value for the substance, (2)
the LEL value, (3) limitations set by manufacturer, or (4)
mathematically determined by multiplying the assigned protection
factor specified for the respirator by the permissible exposure
limit, short term exposure limit, ceiling limit, peak, or another
occupational exposure limit used for the hazardous substance.
Paul Schulte of NIOSH (Exs. 9-13, 13-11-1, and 16-4) recommended
that employers use the RELs, or in the absence of a REL, another appropriate
exposure limit. Schulte also stated that, for both regulated and non-
regulated substances, the MUC for any respirator other than a pressure-
demand SCBA should never exceed the IDLH value. Schulte noted further
that NIOSH did not agree with the use of the LEL as an appropriate
respirator-selection factor for MUCs unless the respirator is the
source of an ignition hazard (e.g., respirators with communication
systems). Accordingly, Schulte (Ex. 9-13) proposed revising the MUC
definition to read as follows:
Maximum use concentration (MUC) means the maximum atmospheric
concentration of a hazardous substance from which an employee can be
expected to be protected when wearing a respirator, and is
determined by the lesser of
APF times (x) exposure limit
The respirator manufacturer's maximum use concentration
for a hazardous substance (if any)
The IDLH, unless the respirator is a positive-pressure,
full facepiece SCBA
Daniel K. Shipp of the International Safety Equipment Association
(ISEA) (Ex. 9-22) commented that ISEA believed that OSHA should not
expand the MUC definition to include MUCs for hazardous substances not
regulated by OSHA, and that the definition should not involve limiting
factors. He indicated that employers should have the flexibility to
determine what to do in these situations. Shipp also stated that the
NIOSH approval labels on chemical cartridges already read "Do not
exceed maximum use concentrations established by regulatory
standards." In this regard, he suggested that OSHA rewrite the MUC
definition to require that MUCs used to select respirators shall not be
exceeded.
Michael Sprinker of the International Chemical Workers Union
Council of the United Food and Commercial Workers Union (Ex. 10-54)
believed that OSHA's definition of MUC should be revised because it is
unclear whether the MUC is a concentration never to be exceeded or a
time weighted average. He also stated that OSHA should require
employers to determine MUCs for substances for which no OSHA PEL is
available, and that these MUCs can be derived from occupational
exposure limits issued by NIOSH, ACGIH, EPA, or the manufacturer.
Robert W. Barr and Linda M. Maillet of Alcoa, Inc. (Exs. 9-26 and
10-31) said that OSHA should not expand the definition and application
of MUCs to hazardous substances it does not regulate because that would
constitute adoption of these exposure limits as OSHA rules. The Alcoa
representatives said that employers should be free to select the
criteria for calculating MUCs based on their own risk assessments.
Also, they did not want the lower NIOSH RELs to replace OSHA PELs in
calculating MUCs. They did not believe that OSHA should specify the LEL
or 10% of the LEL as a limiting factor because LEL is an independent
indicator of a physical hazard. They asserted that respirator users who
could be exposed to an explosive level of a substance must not enter
such an area because of the physical hazard--the characteristics of
their respirators are irrelevant in such situations. Similarly, Daniel
P. Adley and William L. Shoup of the Society for Protective Coatings
(Ex. 9-10) did not agree with the "or any other exposure limit" in
the definition of MUC, which would give regulatory authority to TLVs,
RELs, and other industry--established exposure limits.
Bill Kojola of the AFL-CIO (Exs. 9-27 and 16-5) believed that OSHA
should expand the definition and application of MUC to include
substances it does not regulate, and that the exposure limits issued by
NIOSH, ACGIH, EPA, or the manufacturer should be used when available.
Pete Stafford of the Building and Construction Trades Department, AFL-
CIO (Ex. 9-29) recommended that OSHA expand the definition of MUC to
include appropriate exposure values because thousands of harmful and
potentially harmful chemicals used in the workplace are not regulated
by OSHA. He indicated that alternative MUCs calculated for chemicals
using a non-OSHA exposure limit should be used when these MUCs are
lower than the MUCs determined from using PELs. He also recommended
that OSHA specify 10% of the LEL as a limiting factor for MUCs.
Stephan C. Graham of the United States Army Center for Health
Promotion and Preventive Medicine (Exs. 9-42, 9-42-1, and 9-42-2)
indicated that OSHA should expand the MUC definition to include
hazardous substances it does not regulate. However, he did not believe
that NIOSH MUCs should be used when they are lower than the MUCs
calculated using OSHA PELs. Rick N. Givens of Augusta Utilities
Department (Ex. 10-2) also agreed that OSHA should require employers to
calculate MUCs for substances that do not have OSHA PELs. Ken M. Wilson
of the Division of Safety & Hygiene, Ohio Board of Water Control (Ex.
10-3) stated that OSHA should require employers to determine MUCs for
substances that have no OSHA PEL because many of these substances can
harm employees.
David L. Spelce (Ex. 10-6) stated that the PELs in 29 CFR 1910.1000
were adopted by OSHA in 1971 and came mostly from the 1968 ACGIH TLVs.
He recommended that OSHA require employers to use the ACGIH TLVs and
AIHA Workplace Environmental Exposure Levels when no OSHA PEL exists.
He indicated that these alternative values also should be used when
they are more stringent than the OSHA PELs. He agreed with OSHA that
when the IDLH level is lower than the calculated MUC, the IDLH
concentration must take precedence. In such circumstances, only the
most protective atmosphere-supplying respirators should be used. He
also stated that IDLH limits should be established based on
toxicological data, but, in the absence of toxicological data, 10% of
the LEL should be used as the limiting factor (i.e., having the same
weight as the IDLH for flammable substances).
Thomas C. O'Connor of the National Grain and Feed Association
(NGFA) (Exs.10-13 and 16-19) recommended a revised MUC definition that
would read as follows:
Maximum use concentration (MUC) * * * usually can be determined
mathematically by multiplying the assigned protection factor
specified for a respirator by the permissible exposure limit or
ceiling value as appropriate. In a situation when such regulatory
limits have not been set by OSHA, the employer may rely on limits
established by non-regulatory organizations based on professional
judgment and the working environment.
However, he (Ex. 10-13) said that NGFA strongly opposes requiring
employers to determine MUCs for substances for which no OSHA PELs are
available. The NGFA also opposed any requirement that employers rely on
MUCs developed by NIOSH, but supported the use of non-OSHA exposure
limits as aids employers can use in establishing MUCs.
Thomas Nelson of NIHS, Inc. (Ex. 10-17) indicated that OSHA should
not require employers to determine MUCs for substances that have no
OSHA PELs. Nelson said that OSHA first must determine when a need for
such exposure limits exists, and then issue new PELs. Furthermore,
Nelson stated that OSHA cannot rely on other groups to establish limits
for OSHA's use. He also said that the only limiting factors that should
be used in calculating MUCs are APFs and IDLHs, and that the Agency
should specify the LEL, or a value close to the LEL (e.g., 90% of the
LEL), when no IDLH exists for a substance.
Lorraine Krupa-Greshman of the American Chemistry Council (ACC)
(Ex. 10-25) indicated that NIOSH MUCs should not be adopted as a
specific requirement, but should remain available for guidance. The ACC
also does not support requiring compliance with NIOSH MUCs when they
are lower than OSHA's MUCs. The ACC recommends a requirement for
employers to determine the appropriate MUCs for substances that do not
have an OSHA PEL. However, employers should be allowed to designate and
document the basis for these MUCs using either the OSHA formula or
other criteria. She stated that the IDLH is a reasonable limit on the
MUC for some types of respirators, and that an IDLH should be based on
health effects. She noted that using the LEL or a percentage of the LEL
to limit MUCs is confusing and inappropriate because an LEL is used to
determine whether an employee can safely enter an area with a fire
hazard, not for selecting respirators.
Frank A. White of ORC Worldwide (Ex. 10-27) stated that OSHA should
not require employers to calculate MUCs for substances that have no
OSHA PEL, but that employers should have the freedom to select the
occupational exposure limits used for calculating MUCs based on their
own risk assessments. He emphasized that it is important that employers
be able to show the documented evidence used to support their MUC
decisions. ORC Worldwide also indicated that OSHA should not expand the
application of MUCs to hazardous substances it does not regulate
because these exposure limits (e.g., developed by chemical
manufacturers, ACGIH, NIOSH, EPA) would become OSHA regulations. He
also stated that OSHA should not enforce the 1994 NIOSH IDLHs, but
instead should continue to rely on those IDLHs that NIOSH developed in
1990. OSHA should not use either the LEL or 10% of the LEL as a
limiting factor because these factors are not health-based, and are
used as indicators of a physical hazard.
Ted Steichen of the American Petroleum Institute (Ex. 9-23)
believed that the determination of MUCs for substances with no OSHA
PELs should be left to the good practices of the employer. He stated
that OSHA would be exceeding its authority if it expanded the
definition and application of MUC to hazardous substances that it does
not regulate. Steichen said that the use of the LEL to limit the MUC is
confusing and inappropriate. He stated that the LEL has no relationship
to the protection provided by a respirator, but is an essential factor
to consider when working with flammable or combustible materials.
Paul Hewett of Exposure Assessment Solutions, Inc. (Ex. 10-60)
believed that OSHA should require employers to determine MUCs for those
substances that have no OSHA PEL. He pointed out that employers already
are required to consider all hazardous substances, including those
substances without an OSHA PEL, under the "recognized hazards"
provision of the general-duty clause of the OSH Act. He recommended
that OSHA indicate, either by regulation or by repeated emphasis in the
preamble of this final standard and in all respirator guidelines, that
these requirements also apply to overexposures involving unregulated
substances. Hewett also stated that OSHA should not require employers
to comply with MUCs calculated using NIOSH RELs when these MUCs are
lower than the MUCs calculated using OSHA PELs. He recommended as well
that OSHA should specify an upper bound on MUCs that is a percentage of
the IDLH for a substance, e.g., the MUC is no more than 25% of the
IDLH.
Michael Watson of the International Brotherhood of Teamsters, AFL-
CIO (Ex. 9-12), Pete Stafford of the Building and Construction Trades
Department, AFL-CIO (Ex. 9-29), and Rick N. Givens of the Augusta
Utilities Department (Ex. 10-2) agreed with using the IDLH as a
limiting factor for MUCs. Givens also recommended that OSHA specify 10%
of the LEL as an additional limiting factor for MUCs.
Michael Runge of the 3M Company (Exs. 9-16, 16-25, and 16-25-2)
said that only APFs and IDLHs should be used to calculate MUCs. The LEL
and eye irritation, as well as all other limitations, already are
considered in the respirator selection process, and do not necessarily
need to be considered when establishing specific MUCs. He did not
support use of 10% of the LEL as a limiting factor, but stated that
OSHA should specify the LEL when no IDLH is available for a chemical.
He also stated that when employers use the REL for an unregulated
contaminant to select a respirator, the APF and MUC principles
specified in the proposal should apply.
Kenneth Bobetich of Mine Safety Appliances (Ex. 9-37) believed that
OSHA's definition of MUC is sufficient to cover the limitations, and
that MUCs should not be based on eye irritation. Tracy C. Fletcher of
Parsons-Odebrecht JV (Ex. 10-1) recommended that OSHA use 10% of the
LEL as an MUC-limiting factor. Accordingly, when the atmosphere reaches
10% of the LEL, the employee should be removed and steps taken to make
the work area safe (e.g., ventilate the area). When the area cannot be
made safe, the employer should provide the employee with a fire-
retardant suit and supplied air.
3. Summary and Conclusions
As noted above in the discussion of the MUC definition, the final
standard will require employers to use an OSHA exposure limit when
available. However, absent an OSHA exposure limit, employers must use
relevant available information combined with informed professional
judgment to determine MUCs. The purpose of this approach is to permit
employers to rely on existing data sources and professional judgment
when determining an MUC that will provide adequate protection for their
employees from hazardous airborne contaminants that have no OSHA
exposure limit.
E. MUCs for Mixtures and Hazard Ratios
1. MUCs for Mixtures
Paragraph (d)(3)(i)(B)(1) requires employers to select respirators
for employee use that maintains the employees exposure to the hazardous
substance at or below the MUC. However, a question arises regarding how
to make these calculations for mixtures. Question 12 in Section VIII.
("Issues") of the proposal addressed this issue by requesting
comments on the proposed MUC for mixtures., About half of the
commenters supported the MUC provisions as proposed, but believed that
insufficient data were available to perform the calculations for
mixtures (Exs. 9-23, 9-37, 10-17, 10-25, and 10-59). Another group of
commenters supported performing the calculations based on information
that each component of a mixture has a non-additive effect on
independent organ systems. In this case, the commenters suggested
either a separate MUC for each component, or lowering the MUC according
to the proportion of each component in the mixture (Exs. 9-12, 9-13, 9-
22, 9-29, and 9-37). Still others recommended lowering the MUC by an
unspecified proportion when individual components of the mixture have
synergistic effects on organ systems (Ex. 9-42), or simply requiring
employers to use supplied-air respirators when employees are exposed to
mixtures (Ex. 10-1).
Daniel K. Shipp of the International Safety Equipment Association
(Ex. 9-22) pointed out that the effect of the mixture on canister/
cartridge service life must be evaluated, and an appropriate change
schedule established for a mixture of gases or vapors. Shipp indicated
that no MUC equation is available for mixtures. He suggested that when
the health effects of a mixture's components are not additive, then each
component should be evaluated separately, and the respirator must be
appropriate for the sum of the individual chemical concentrations.
Kenneth Bobetich of Mine Safety Appliances (Ex. 9-37) noted that no
evidence exists to indicate that respirator performance is different
when the exposure is to a mixture of particulates versus a single
particulate. However, the effect of a mixture of gases or vapors on
canister/cartridge service life must be evaluated, and an appropriate
change schedule established. He further mentioned that Dr. Gerry Wood
of LANL is conducting a study to evaluate the effect of mixtures on
service life, and is developing a model to predict cartridge service
life. Bobetich indicated that when the health effects of the mixture
components are on the same organ system and these effects are additive,
an additive formula can be used to establish the PEL for the mixture.
However, when the health effects are not additive, then each component
should be evaluated individually and the respirator must be appropriate
for the sum of the individual chemical concentrations.
Thomas Nelson of NIHS, Inc. (Ex. 10-17) said that, because
exposures to multiple organic vapors will affect the service life of a
cartridge, the employer already is required to consider multiple
contaminants in setting a cartridge change schedule. He recommended
that, to determine the MUC for a mixture that affects the same organ
system, employers should assume that the health effects of each
component are additive.
Frank A. White of ORC Worldwide (Ex. 10-27) indicated that exposure
to multiple gas or vapor contaminants may affect the service life of
respirator filters and cartridges differently than exposure to a single
contaminant. He, too, mentioned that Dr. Gerry Wood is working on this
issue with NIOSH, and that a service life calculation model for
multiple contaminants will soon be available. He emphasized that the
more important consideration in determining MUCs for mixtures is the
health effects of multiple contaminants. He stated that the employers
are in the best position to apply recommendations from chemical
manufacturers and information on health effects to their specific
workplaces. He noted that industrial hygienists should determine if the
contaminants have additive health effects, and they should use the
additive mixture formula set by ACGIH and OSHA to calculate the MUC.
Michael Watson of International Brotherhood of Teamsters, AFL-CIO
(Ex. 9-12) and Pete Stafford of the Building and Construction Trades
Department, A FL-CIO (Ex. 9-29) stated:
The presence of multiple contaminants in the workplace should be
taken into consideration when the employer determines the MUC and
respirator change schedules for gases and vapors. Mixtures may have
similar effects on chemical cartridge loading, so the MUC of each
component of a mixture should be lowered in proportion to its
percentage of the total concentration of contaminants in air.
Paul Schulte of NIOSH (Exs. 9-13, 13-11-1, and 16-4) recommended
that the equation C1/MUC1 + C2/
MUC2 + * * * + Cn/MUCn = 1 should be
used to determine MUCs for mixtures. He asserted that the MUC would be
safe only when the result is [gteqt]1. Schulte also stated that the
rated service life of the cartridge may be shortened during exposure to
a mixture (i.e., one or more of the mixture's components may break
through before the rated end-of-service-life).
Ted Steichen of American Petroleum Institute (Ex. 9-23) indicated
that no data are available comparing respirator performance during
exposure to multiple contaminants and exposure to single contaminants,
and that it is impractical to discuss establishing different MUCs for
mixtures. Stephan C. Graham of the United States Army Center for Health
Promotion and Preventive Medicine (Exs. 9-42, 9-42-1, and 9-42-2)
stated that MUCs for mixtures should differ from MUCs for single
compounds depending on whether the health effects are additive or
synergistic.
Tracy C. Fletcher of Parsons-Odebrecht JV (Ex. 10-1) believed that
supplied-air respirators should be used to eliminate the risk of filter
failure caused by chemical reactions that may occur among the
components of a mixture. Lorraine Krupa-Greshman of the American
Chemistry Council (ACC) (Ex. 10-25) indicated that by addressing
contaminants with additive effects, 29 CFR 1910.1000(d)(2)(i) and the
proposal provide adequate means of achieving suitable protection. Also,
she said that MUCs can be developed for multiple contaminants that have
independent health effects by using the change schedule provisions of
1910.134(d)(3)(iii)(B)(2). The ACC does not believe that adequate
information and data are available to develop MUCs for mixtures with
synergistic effects.
Lisa M. Brosseau of the University of Minnesota (Ex. 10-59)
believed that the issue of mixtures, as addressed in the proposal, is
confusing and incorrect. She stated that the only requirements needed
are to assure that respirators have the required filters and that gases
and vapors have appropriate cartridges.
2. Use of Hazard Ratios
Michael Runge of the 3M Company (Ex. 9-16), Daniel K. Shipp of the
International Safety Equipment Association (Ex. 9-22), and Lisa M.
Brosseau of the University of Minnesota (Ex. 10'59) supported another
method for selecting respirators, the hazard ratio (HR). The HR is
defined as the ratio of the workplace concentration of an airborne
contaminant divided by the occupational exposure limit (e.g., PEL). Any
respirator that has an APF equal to or greater than the HR may be
selected. They stated that the HR is more useful to employers than MUCs
because employers likely will have information on airborne
concentrations and occupational exposure limits when selecting
respirators. Both Runge and Shipp said that the HR is similar to the
MUC. Brosseau noted that it makes more sense to use the HR rather than
the MUC to select respirators, and she recommended that OSHA require
the HR method, and use the MUC as guidance.
OSHA is not adopting hazard ratios under this final rulemaking
because it was not addressed in the notice of proposed rulemaking.
Accordingly, OSHA would have to provide the public with notice and an
opportunity for comment on this issue before taking such action.
3. Summary and Conclusions
OSHA agrees with the commenters who stated that the data on
mixtures are limited, and that no revision is needed for OSHA's
proposed single-contaminant MUC definition (Exs. 9-23, 9-37, 10-17, 10-
25, and 10-59). The existing requirement for setting change schedules
for respirator cartridges and canisters specified in 29 CFR 1910.134
(d)(3)(iii)(B)(2) already requires that employers consider the effects
of each component in organic vapor mixtures when they develop change
schedules. The Agency recognizes that reliable methods are not
available to develop MUCs for mixtures based on whether the components
of the mixture act additively or synergistically, and whether they
affect the same organ or different organs. Therefore, OSHA will rely on
the provisions at 29 CFR 1910.1000(d)(2)(i) to assist employers in
calculating MUCs.
While the determination of MUCs and service life are both necessary
for respirator selection, they should not be confused. MUCs can be used
to decide if a certain type of respirator even qualifies for
consideration for use in defined workplace concentrations. Service life
estimation identifies how long a properly selected respirator can be
expected to provide worker protection and, therefore, is useful for
setting change schedules.
OSHA has established at 29 CFR 1910.1000(d)(2)(i) an equivalent
exposure requirement for mixtures of air contaminants. Accordingly,
MUCs for respirators used in a mixture of contaminants must satisfy the
following equation:
Em = (C1 / L1 + C2 /
L2) + * * * + (Cn / Ln)
Where:
Em is the equivalent exposure for the mixture
C is the concentration of a particular contaminant
L is the exposure limit for that substance
The value of Em shall not exceed unity (1).
OSHA is maintaining the MUC as a requirement in the final standard
for determining the maximum concentration of an airborne contaminant
from which a respirator will protect an employee. In addition, the
Agency cannot revise the final rule to mandate the use of hazard ratios
because the regulated community must have adequate notice of, and an
opportunity to comment on, any such revision to the standard.
F. MUC Provisions
1. Paragraph (d)(3)(i)(B)--MUC Provisions
These final requirements consist of three separate paragraphs
((d)(3)(i)(B)(1) through (d)(3)(i)(B)(3)). Paragraph (d)(3)(i)(B)(1),
which sets the requirements for the use and application of MUCs, reads,
"The employer must select a respirator for employee use that maintains
the employee's exposure to the hazardous substance, when measured
outside the respirator, at or below the MUC." This paragraph, which
has the same designation in the proposal, requires employers to select
respirators for employee protection that are appropriate to the ambient
levels of the hazardous substance found in the workplace, i.e., that
the ambient level of the hazardous substance must never exceed the MUC,
which is the exposure limit specified for the hazardous substance
multiplied by the respirator's APF. Accordingly, this provision ensures
that employers maintain employees' direct exposure to hazardous
substances (i.e., inside the respirator) below levels specified by
OSHA's Z tables and substance-specific standards, and, when OSHA has no
standards, below exposure levels determined by the employer. Therefore,
this provision provides employee protection consistent with existing
regulatory requirements and prevailing industrial-hygiene practice.
In the MUC provision following paragraph (d)(3)(i)(B)(1) in the
proposal, OSHA had incorporated a note that stated: "MUCs are
effective only when the employer has a continuing, effective
respiratory protection program as specified by 29 CFR 1910.134,
including training, fit testing, maintenance and use requirements."
The Agency is removing this note because the program already is
required under its Respiratory Protection Standard for all employers
using respirators, and OSHA believes that duplicating this information
in a note is unnecessary.
The second MUC provision in the proposal, paragraph
(d)(3)(i)(B)(2), required employers to use MUCs determined by
respirator manufacturers when those MUCs were lower than the MUCs
determined using the general calculation (i.e., MUC = APF x PEL).
Several commenters objected to the proposed provision, stating that it
gave regulatory status to manufacturer's MUCs (e.g., Exs. 9-10, 9-22,
9-23, 9-24, 9-26, and 10-13). However, the Agency often defers in its
rules to instructions and other documents published by manufacturers
(e.g., no fewer than seven provisions of OSHA's Respiratory Protection
Standard refer to manufacturers' instructions or recommendations).
Nevertheless, the Agency believes that the proposed provision is
unnecessary because using the general calculation specified in the MUC
definition is an accepted safe practice in the industrial-hygiene
community.
Paragraph (d)(3)(i)(B)(2) of the final MUC provisions (which was
designated as paragraph (d)(3)(i)(B)(3) in the proposal) specifies that
employers must not use MUCs to select respirators for employees who are
entering an IDLH atmosphere. OSHA previously specified the requirements
for selecting respirators for use in IDLH atmospheres in paragraph
(d)(2) of its Respiratory Protection Standard. Paragraph (d)(2)
requires employers to select for this purpose a full facepiece
pressure-demand SCBA certified by NIOSH to have a service life of at
least 30 minutes, or a combination full facepiece pressure-demand
supplied-air respirator with an auxiliary self-contained air supply. In
the preamble to the final Respiratory Protection Standard, the Agency
justified selecting these respirators as follows: "In [IDLH]
atmospheres there is no tolerance for respirator failure. This record
supported OSHA's preamble statement that IDLH atmospheres `require the
most protective types of respirators for workers' " (59 FR 58896).
Commenters to the APF proposal, including NIOSH, ANSI, and
representatives of both labor and management, agreed that employees
should use these respirators, which are the most protective respirators
available, when exposed to IDLH atmospheres. (See 63 FR 1201 for a more
complete discussion of these comments.)
Ted Steichen of the American Petroleum Institute (Ex. 9-23)
requested that OSHA clarify that a pressure-demand full facepiece SAR
with auxiliary SCBA can be used at an APF higher than 1,000. He said
that positive-pressure SARs with auxiliary SCBAs often are used by the
petroleum industry for non-emergency work in high-hazard operations
(e.g., cleaning refinery flare systems) that may involve potential
exposures greater than 1,000 times the PEL. Under proposed Table 1, he
questioned whether OSHA would consider this use of SARs with auxiliary
SCBAs to be acceptable. The Agency notes that paragraph (d)(2)(i)(B) of
its Respiratory Protection Standard already permits employers to use a
combination full facepiece pressure-demand supplied-air respirator
(SAR) with auxiliary self-contained air supply in IDLH atmospheres.
Also, paragraph (d)(3)(i)(A) of this final standard states, "When
using a combination respirator * * * employers must ensure that the
assigned protection factor is appropriate to the mode of operation in
which the respirator is being used." In this case, the combination
pressure-demand full facepiece SAR with auxiliary SCBA respirator is
equivalent to an SCBA, and, therefore, the APF for an SCBA applies.
The last MUC provision, proposed paragraph (d)(3)(i)(B)(4), would
have required that "[w]hen the calculated MUC exceeds another limiting
factor such as the IDLH level for a hazardous substance, the lower
explosive limit (LEL), or the performance limits of the cartridge or
canister, then employers must set the maximum MUC at that lower
limit." Accordingly, the IDLH limits for hazardous substances would
take precedence over the calculated MUC when the IDLH limits result in
lower employee exposures to the hazardous substances. Consequently,
this provision increases employee protection against these hazardous
substances. OSHA is retaining a revised version of this proposed
provision in the final rule (redesignated as paragraph
(d)(3)(i)(B)(3)). The remaining paragraphs of this subsection discuss
the revisions.
The previous discussion of MUCs for substances with no OSHA PEL or
other limiting factors (see subsection 2 ("MUCs for Substances with No
OSHA PEL or Other Limiting Factor") of this section) addressed the use
of the LEL as a limiting factor to be considered when calculating the
MUC. NIOSH did not agree with the use of the LEL as a limiting factor
for MUCs in respirator selection unless the respirator is the source of
an ignition hazard (Ex. 9-13). Alcoa, Inc. did not believe OSHA should
use the LEL as a limiting factor for MUCs since the LEL "is not
health-based, rather it is an independent indicator of a physical
hazard" (Ex. 10-31). The American Chemical Council commented using the
LEL to set MUCs was confusing and inappropriate, because the LEL is
used to determine whether an employee can safely enter an area with a
fire hazard, not for selecting respirators (Ex. 10-25). The American
Petroleum Institute also questioned the use of the LEL to limit the MUC
because the LEL has no relationship to the protection provided by a
respirator, but is a factor to consider when working with flammable or
combustible substances (Ex. 9-23). The 3M Company stated that the LEL
already is required under the Respiratory Protection Standard when
selecting respirators, and does not need to be taken into account when
establishing specific MUCs (Ex. 9-16).
The Agency agrees with these commenters that the LEL is not
appropriate as a limiting factor in setting MUCs. Therefore, OSHA
removed from paragraph (d)(3)(i)(B)(3) in the final rule the language
that identified the LEL as a limiting factor in setting MUCs. The
Agency made this revision to the proposal because the LEL is not
related to the performance of the respirator, but is an independent
indicator of a physical hazard (i.e., the flammability or
combustibility of a substance) that already must be considered when
determining whether an employee can safely enter a hazardous area.
The revised and redesignated final paragraph (d)(3)(i)(B)(3) now
reads as follows:
(3) When the calculated MUC exceeds the IDLH level for a
hazardous substance, or the performance limits of the cartridge or
canister, then employers must set the maximum MUC at that lower
limit.
G. Superseding the Respirator Selection Provisions of Substance-
Specific Standards in Parts 1910, 1915, and 1926
1. Introduction
OSHA proposed to revise the provisions in its substance-specific
standards under 29 CFR parts 1910, 1915, and 1926 that regulate APFs
(except the APF requirements for the 1,3-Butadiene Standard at 29 CFR
1910.1051). These substance-specific standards specify numerous
requirements for regulating employee exposure to toxic substances. The
proposed revisions would have removed the APF tables from these
standards, as well as any references to these tables, and would have
replaced them with a reference to the APF and MUC provisions specified
by proposed paragraphs (d)(3)(i)(A) and (d)(3)(i)(B) of the Respiratory
Protection Standard at 29 CFR 1910.134. In justifying these proposed
revisions, the Agency stated that the proposed revisions would simplify
compliance for employers by removing many APF requirements across its
substance-specific standards. The proposed revisions would enhance
consolidation and uniformity of these requirements, and conform them to
each other and to the general APF and MUC requirements specified by 29
CFR 1910.134 (68 FR 34107).
As noted elsewhere in this preamble to the final APF rule, OSHA
developed the final APFs using the best available evidence. The
development of these final APFs included a careful review of the
comments, testimony, data, and other evidence submitted to the
rulemaking record, a quantitative (i.e., statistical) analysis of the
results from WPF studies performed among workers wearing air-purifying
half mask respirators (both filtering facepieces and elastomerics)
discussed above in this preamble, and a thorough quantitative and
qualitative review of existing WPF and SWPF studies performed with
other types of respirators. Using the best data and analytic techniques
available, as well as the extensive comments and testimony provided to
the rulemaking record, lends a high degree of reliability and validity
to the final APF determinations.
The Agency believes that the final APFs developed under this
rulemaking will improve the substance-specific standards. The final
APFs will provide employers with confidence that their employees will
receive the level of protection from airborne contaminants signified by
these APFs when they implement a respiratory protection program that
complies with the requirements of 29 CFR 1910.134. In addition,
applying the final APFs to the substance-specific standards is
consistent with OSHA's goal of bringing uniformity to its respiratory
protection requirements. Moreover, protection for workers likely will
be increased because the final APFs result in regulatory consistency,
enhanced employer compliance, and reduced the compliance burden on the
regulated community, and, consequently, further increases the
protection afforded to employees who use respirators.
In its Respiratory Protection Standard, OSHA noted that the revised
standard was to "serve as a "building block" standard with respect
to future standards that may contain respiratory protection
requirements." (See 63 FR 1265, 1998.) However, in the proposed APF
rulemaking that would provide generic APFs and MUCs as part of the
Respiratory Protection Standard, the Agency decided to retain former
respirator selection provisions in the existing substance-specific
standards that it found supplemented or supplanted the proposed APFs
and MUCs (e.g., organic vapor cartridge and canister procedures,
prohibiting use of filtering facepieces or half mask respirators). OSHA
did so because these provisions enhance the respirator protection
afforded to employees.
2. Comments Regarding the Respirator Selection Provisions of the 1,3-
Butadiene Standard
The former respirator selection provisions being retained in this
final rule include those provisions in the 1,3-Butadiene (BD) Standard.
In issue 13 of the proposed APF rule (68 FR 34112), OSHA asked if
exclusion of this standard was warranted. The responses to this
question addressed only the service life requirement for cartridges
used to absorb atmospheric BD. Typical of these responses is the
following comment from the 3M Company:
A short service life does not affect the ability of a specific
respirator to reduce a concentration of a contaminant below the PEL.
* * * [W]ith the cartridge change requirements in 1910.134 there is
no need to limit the use of organic vapor cartridges or canisters to
specific levels of BD. The employer is required to determine a
useful service life. If that service life is very short, the
employer will need to determine if the replacement schedule is
realistic. (Ex. 18-7.)
However, two other commenters made important observations. First,
the American Chemistry Council representative noted that "[E]xclusion
of [the BD] standard is reasonable since this standard has a more
comprehensive respirator section that includes end of service life
specifications' (Ex. 10-25). Second, ORC Worldwide stated, "Excluding
[BD] is warranted. Additional verbiage relative to service lives developed
under a negotiated rulemaking process should not be changed" (Ex. 10-
27).
Commenters who recommended adopting the change-out schedule
provisions of 29 CFR 1910.134 provided no compelling rationale for
disturbing the extensive change-out schedules developed for the BD
Standard on the recommendation of industry and labor representatives .
Substituting the performance-based provisions that regulate change
schedules under 29 CFR 1910.134 for the existing BD Standard's change
schedule provisions for the sake of convenience is insufficient
justification for revisiting these relatively recently promulgated
provisions. In this regard, the latter two commenters clearly
recognized the importance of the process that resulted in the existing
change schedule requirements.
In the preamble to the final BD Standard, the Agency reviewed test
data that demonstrated short breakthrough times for BD concentrations
above 50 ppm. Accordingly, these short breakthrough times justified
setting at 50 ppm the upper limit at which employees can use air-
purifying respirators for protection against BD exposures. The Agency
used these data to develop change schedules for cartridges and
canisters that are unique for BD exposures (see Table 1 of the BD
Standard). OSHA reviewed the test data when it published the final
standard in 1996 and found that these conclusions remain valid. The
Agency believes that it would impose an unnecessary burden on employers
who are subject to the BD Standard to require them to repeat the review
already conducted by OSHA on BD breakthrough times, and then develop
their own change-out schedules under 29 CFR 1910.134. Moreover,
employee protection from exposure to BD is unlikely to be increased.
The Agency acknowledged in the preamble to the final BD Standard
that it took a conservative approach to employee protection. In this
regard, OSHA noted that its "decision to rely on the more protective
NIOSH APFs is based on evidence showing that organic vapor cartridges
and canisters have limited capacity for adsorbing BD and may have too
short a service life when used in environments containing greater than
50 ppm BD." (See 61 FR 56816.) With regard to the change-out
schedules, the Agency concluded:
Allowing for a reasonable margin of protection, and given that
test data were available only for a few makes of cartridges and
canisters, OSHA believes that air-purifying devices should not be
used for protection against BD present in concentrations greater
than 50 ppm, or 50 times the 1 ppm PEL. Thus, OSHA finds that the
ANSI APFs of 100 for full facepiece, air-purifying respirators and
1,000 for PAPRs equipped with tight-fitting facepieces are
inappropriate for selecting respirators for BD.
Accordingly, OSHA is retaining the respirator selection provisions
of the BD Standard to avoid imposing on employers the new burden of
developing their own change-out schedules, and to ensure maximum
protection for employees exposed to BD.
3. Comments Regarding the Respirator Selection Provisions of Other
Substance-Specific Standards
The Agency proposed to retain a number of special respirator
selection provisions in the existing substance-specific standards. In
this regard, OSHA noted that the respirator selection requirements
proposed for retention were developed in rulemakings to provide
protection against a hazardous characteristic or condition that is
unique to the regulated substance. Additionally, the Agency stated that
retaining these requirements would not increase the existing employer
burden because they already must comply with these requirements.
Consequently, retaining these provisions would maintain the level of
respiratory protection currently afforded to employees. These
provisions were in the substance-specific standards regulating employee
exposure to vinyl chloride, inorganic arsenic, asbestos, benzene, coke
oven emissions, cotton dust, ethylene oxide, and formaldehyde.
Under issue 13 in the proposal, OSHA requested comments on the need
to standardize the respirator selection provisions being proposed for
retention. The Agency received numerous comments and hearing testimony
on this issue. Most of these comments and testimony encouraged OSHA not
to retain these provisions in their existing form, but instead to
subsume these provisions under the Respiratory Protection Standard at
29 CFR 1910.134. An example of such a recommendation was provided by
the 3M Company (3M) when it stated, in its hearing testimony, "It is
neither necessary nor justified to retain any of the specific
requirements in the substance-specific standards. * * * They do not
reflect the changes in science and technology, respirator design,
respirator certification, or respirator regulation under 29 CFR
1910.134" (Tr. at 393). In subsequent testimony, a representative from
3M stated, "We contend that requiring separate respirator APFs and
selection requirements in the substance-specific standards as proposed
would only add confusion to the respirator selection process, and is
not justified by any scientific or practical evidence" (Tr. at 394).
Thomas Nelson of NIHS, Inc., provided similar rationale in support of
standardizing these provisions, stating:
The proposal would retain information [on] cartridge change
schedules, filter selection and some specific respirator selection
requirements in the substance specific standards. None of these
requirements are necessary in the substance specific standard[s].
The current 1910.134 with the addition of an assigned protection
factor table contains requirements that are protective. (Ex. 18-9.)
Many of these comments addressed issues involving single substance-
specific standards, including their cartridge, canister, and filter
requirements. The following paragraphs provide a summary of the
comments that pertain to individual substance-specific standards, as
well as OSHA's response to these comments.
Inorganic Arsenic (29 CFR 1910.1018). A commenter wanted
OSHA to "[c]larify if filtering facepieces will be acceptable [under
this standard]," and asserted that requiring "gas masks or SARs for
exposures above the PEL is unnecessary (Ex. 9-5). Two commenters, the
Mine Safety Appliances Co., and the 3M Company, questioned the need to
require a HEPA filter when using a cartridge or canister for exposures
above a specified limit (Exs. 9-37, 18-7), while one of these
commenters claimed that any filter approved by NIOSH under 42 CFR part
84 would provide the required level of filter efficiency (Ex. 18-7).
The Agency did not address, as part of this rulemaking, the use of
filtering facepieces during inorganic arsenic exposures. This question
deals with compliance. The other two commenters provided no basis for
questioning the requirement for HEPA filters, while the issue of
filters approved under 42 CFR part 84 is addressed below (see section
entitled "Substituting N95 Filters for HEPA Filters").
Asbestos (29 CFR 1910.1001 and 29 CFR 1926.1101). The 3M
Company (3M) objected to the provision in this standard that prohibits
the use of disposable half masks, but permits the use of elastomeric
respirators, at asbestos concentrations that are 10 times the PEL (Ex.
18-7). In these comments 3M stated that this disparity "is counter to
OSHA's analysis of WPF data that does not show a difference
between filtering facepieces and elastomeric facepieces." The 3M
Company continued by noting that NIOSH stated that the aerosol size
used in its respirator certification test ensures that filter
performance will be at least as efficient "for essentially all other
aerosol sizes" (see 60 FR 30344). While this comment implies that
NIOSH would accept filtering facepieces for protection against
asbestos, another commenter observed that the 1997 NIOSH Pocket Guide
to Chemical Hazards expressly prohibits such use (Ex. 18-5).
The rebuttal made by the last commenter indicates that 3M's
concerns regarding the use of disposable respirators are controversial.
Consequently, revision would require a new rulemaking.
Coke Oven Emissions (29 CFR 1910.1029). A 3M
representative asserted that OSHA made an error when it proposed to
revise the term "single-use respirator" to "filtering facepiece
respirators" in item (b)(1) of Table 1 in paragraph (g)(3) of this
standard (Ex. 18-7). This commenter supported this assertion by noting
that "[t]he `single use type' respirator was a term that NIOSH started
after promulgation of the coke oven emission standard," and that
"[d]isposable dust/mist respirators are not prohibited from use under
the * * * standard." In conclusion, this commenter remarked that, by
revising the term "single-use respirator" to "filtering facepiece
respirators," the Agency is "prohibiting disposable particulate
respirators from being used, which was not the intent of the original
standard." However, another commenter took exception to removing the
proposed prohibition against all filtering facepiece respirators (Ex.
18-5), claiming that the particle size of coke oven emissions is
unknown, and that coke oven fumes may degrade the electrostatic filters
used in filtering facepieces. This commenter asserted that employers
should use only HEPA filter cartridges, or P100 filtering facepieces
that respirator manufacturers demonstrate will not degrade when exposed
to coke oven fumes.
The Agency agrees with the first commenter that the term "single-
use respirator" is outdated. It believes that the regulated community
now designates these respirators as filtering facepiece respirators.
Accordingly, the definition of filtering facepiece respirators in
paragraph (b) of 29 CFR 1910.134 consists of three key
characteristics--they function under negative pressure, are used
against particulates and vapors, and consist of a filtering medium that
is an integral part of the facepiece or that constitutes the entire
facepiece. These characteristics also describe single-use respirators.
This definition does not specify the functional characteristics of
filtering facepieces, only their structural features. In this regard,
both filtering facepiece and single-use respirators generally are
considered disposable, with the period of effectiveness determined by
the functional characteristics of either respirator. Therefore, because
single-use and filtering facepiece respirators are identical with
regard to their structural characteristics, OSHA is retaining the
proposed terminology in the final APF standard. However, while
paragraph (b)(1) of the Table I in the Coke Oven Emissions Standard
prohibits using a single-use, filtering facepiece respirator, paragraph
(b)(2) of this table permits its use when it functions as a
"particulate filter respirator." Accordingly, employers may select
filtering facepiece respirators when employees are exposed to coke oven
emissions and those emissions (1) consist solely of particulates, and
(2) the exposure conditions are no more than 10 times the PEL for coke
oven emissions. Finally, OSHA simply cannot adopt the recommendation of
the second commenter to use only P100 filtering facepieces under these
conditions as this issue was not part of this rulemaking.
Cotton Dust (29 CFR 1910.1043). The comments concerning
this standard addressed whether filtering facepieces used to protect
employees against cotton dust exposure should retain the current APF of
5 or be upgraded to an APF of 10. In this regard, one commenter
believed that revising this standard to upgrade the APF of filtering
facepieces to 10 would be consistent with the results of OSHA's
statistical analysis of WPF studies for filtering facepiece respirators
(Ex. 18-7). This commenter stated, "[F]iltering facepieces should have
the same APF of 10 for cotton dust as they would for all other dusts.
Filtering facepieces do not show selective performance to cotton dust
versus other aerosols." Three additional commenters echoed a similar
concern with regard to filtering facepieces used against cotton dust.
Two of these commenters noted that no technical reason exists "to
reduce the APF to 5 for filtering facepieces" (Exs. 9-22 and 9-37),
while the third commenter stated that "[n]ot allowing filtering
facepieces for greater than 5 times the PEL is inconsistent with an APF
of 10 indicated in [proposed] Table 1" (Ex. 9-42).
Several commenters responded negatively to the recommendations to
raise the APF from 5 to 10 for filtering facepieces used for protection
against cotton dust (Exs. 12-7-1 and 18-5; Tr. at 41-43). However,
these commenters provided no technical or safety-and-health rationale
for their position. Typical of these comments was the following
statement made at the rulemaking hearing by one of the participants:
"If OSHA goes ahead and assigns a 10 * * * for [filtering facepieces]
for the cotton dust standard * * *, you're going against what was
established way back when and settled by the court [at] an APF of 5."
(Tr. at 43.)
The first set of commenters recommended revising this standard to
raise the APF for filtering facepieces from 5 to 10, consistent with
the APF for filtering facepieces proposed for 29 CFR 1910.134. However,
the Agency did not propose to raise the APF for filtering facepieces
used against cotton dust, and the record is inadequate to make that
decision at this time. The second set of comments noted that revising
the APF from 5 to 10 for filtering facepieces used during exposures to
cotton dust would be foreclosed by the court's decision in Minnesota
Mining and Manufacturing Co. v. OSHA, 825 F.2d 482 (D.C. Cir. 1987);
this decision upheld the Cotton Dust Standard's assignment of an APF of
5 for disposable respirators. While OSHA is not revising the APF for
filtering facepieces used against cotton dust at this time, the Agency
notes that the court's decision in this case does not preclude it from
revising the Cotton Dust Standard in the future based on an appropriate
rulemaking record.
4. Change-Out Schedules for Vinyl Chloride (29 CFR 1910.1017), Benzene
(29 CFR 1910.1028), Formaldehyde (29 CFR 1910.1048), and Ethylene Oxide
(29 CFR 1910.1047)
The International Safety Equipment Association (ISEA), the Mine
Safety Appliances Co., and the 3M Company (3M) requested OSHA to remove
the existing cartridge change-out schedules under the Vinyl Chloride
Standard and replace them with the change-out schedule provisions of 29
CFR 1910.134 (Exs. 9-22, 9-37, and 18-7). In its comments on this
issue, 3M stated that "the nature of toxicity of any analyte does not
affect the service life of a chemical cartridge" (Ex. 18-7). ISEA and
3M submitted similar comments regarding the existing cartridge change-
out schedules in the Benzene Standard (Exs. 9-22 and 18-7).
Accordingly, 3M noted that the Agency should not limit cartridge
selection to only organic vapor
cartridges specified for benzene absorption, but should expand the
permitted cartridges to organic vapor cartridges for acid gas or
formaldehyde absorption, as well as multi-gas cartridges (Ex. 18-7).
The three commenters also recommended that OSHA remove the requirements
for cartridges, filters, and the cartridge change-out schedules in the
Ethylene Oxide Standard, as well as the specifications for cartridges/
canisters and change-out schedules in the Formaldehyde Standard,
asserting that employers could refer to 29 CFR 1910.134 to obtain the
necessary information (Exs. 9-22, 9-37, and 18-7).
In response to these commenters, the Agency notes that it believes
that the minimum change-out schedules specified by these standards
ensure that employers use the designated respirators at appropriate
concentration levels of the regulated substance. OSHA also recognizes
that retaining these specifications may limit employers' flexibility in
adopting change-out schedules. However, it considers this limitation
justified because the specified change-out schedules provide a high
level of protection for employees against the dangerous properties of
these substances. In addition, adopting the change-out schedule
provisions of 29 CFR 1910.134 for current OSHA health standards is
beyond the scope of this APF rulemaking. The Agency cannot make
revisions to this final rule based on these comments because the
regulated community must have adequate notice of, and an opportunity to
comment on, any proposed revisions.
5. Miscellaneous Comments Regarding Superseding Other Substance-
Specific Standards
A number of comments were general, and did not address a single
substance-specific standard. These comments centered on respirator
selection issues that involved two or more of the substance-specific
standards, such as HEPA filters and training. The following paragraphs
identify the issues addressed in these comments, and provide a summary
of the comments that address these general issues, including OSHA s
response to them.
Skin absorption and eye irritation. Three commenters
argued that it was unnecessary to preclude the use of half masks
against eye irritants in the Ethylene Oxide, Methylene Chloride, and
Formaldehyde standards when employees wear appropriate eye protection
with half masks (Exs. 9-22, 9-37, and 9-42). A fourth commenter made a
similar statement regarding protection against eye irritants, but did
not identify any specific substances (Ex. 9-59). One of these
commenters asked, "Why make it a requirement to wear eye protection
unless the concentrations are at irritant levels?" (See Ex. 9-42.)
This commenter also noted that OSHA does not permit the use of half
mask respirators during exposure to arsenic trichloride, but did not
apply this prohibition to other chemicals that employees may absorb
rapidly through the skin. This commenter recommended that the Agency
"[p]rovide consistent recommendations that involve chemicals that can
be absorbed through the skin in significant amounts (e.g., chemicals
with PEL or TLV with `skin' notations)." Another commenter took a
different approach to this issue, proposing that OSHA should "[r]emove
all references to [the] use of respirators for protection from
substances that can be absorbed through the skin or irritate the skin
or eyes. There are other ways that the skin can be protected" (Ex. 10-
59).
The purpose of this rulemaking was to provide the regulated
community with notice of, and an opportunity to comment on, specific
respirator selection provisions that the Agency proposed for revision.
In this regard, OSHA proposed no revisions to any requirements in the
substance-specific standards that addressed protection against eye or
skin irritants. Accordingly, these provisions will remain intact. The
Agency believes that the requirements of existing substance-specific
standards that specify the use of protective clothing and the other
personal protective equipment requirements of 29 CFR 1910 subpart D
will prevent serious skin absorption of toxic substances. Moreover,
provisions in the substance-specific standards that require the use of
full facepiece respirators and other high-end respirators for eye
protection will provide employees with an integrated protection system
that assures maximum respiratory and eye protection.
HEPA Filters. Several commenters took exception to
requirements in many substance-specific standards that some respirators
use HEPA filters. For example, one commenter stated that NIOSH's
updated respirator testing protocol in 42 CFR 84 eliminated the need
for HEPA filters (Ex. 9-22). Similarly, a second commenter noted that
HEPA filters were no longer listed in the NIOSH certification
categories, and that OSHA should update the language in the Respiratory
Protection Standard to be consistent with these categories (Ex. 10-59).
A third commenter recommended that the Agency remove references to HEPA
filters from a number of its substance-specific standards because
"[p]article properties such as size and form are no longer needed in
filter selection" (Ex. 9-37). Another commenter stated that P100
filters were equivalent to HEPA filters, and that OSHA should
"[p]rovide clear generic guidance on when HEPA or P100 filters should
be used, as opposed to another less efficient filter"(Ex. 9-42).
In addressing other issues, one commenter stated that OSHA would be
breaching an earlier decision if it superseded dust-mist-fume
respirators with respirators using HEPA filters at lead levels that are
equal to or below 0.5 mg/m3 (Ex. 10-4).\11\ Another
commenter recommended limiting the use of all electrostatic (fiber)
filters (Ex. 18-5). This commenter based this recommendation on
evidence presented at the 1994 NIOSH hearing on the proposed filter
certification requirements of 42 CFR 84. This commenter stated that the
evidence showed, when tested with a heated DEHP aerosol challenge
agent, the average filter efficiency for electrostatic P100 filters was
less than the average filter efficiency for respirators that used a
mechanical filter media. In one of these tests, the average filter
efficiency for a P100 electrostatic filter was as low as 84.5%.
---------------------------------------------------------------------------
\11\ OSHA published this decision at 44 FR 5446 (January 26,
1979).
---------------------------------------------------------------------------
While it is beyond the scope of this rulemaking to make the
revisions recommended by these commenters, the Agency notes that the
definition of HEPA filters in paragraph (b) of 29 CFR 1910.134 equates
these filters with high-end filters tested under the NIOSH
certification scheme specified by 42 CFR 84. In this regard, the
definition notes that, under 42 CFR 84, HEPA filters are equivalent to
the N100, R100, and P100 particulate filters certified by NIOSH.
Therefore, the Respiratory Protection Standard already describes HEPA
filters in language that equates them to N100, R100, and P100 filters
certified by NIOSH (i.e., the terms are interchangeable). OSHA
Directive No. CPL 2-0.120 of September 25, 1998 ("Inspection
Procedures for the Respiratory Protection Standard") also states,
"When HEPA filters are required by an OSHA standard, N100, R100, and
P100 filters can be used to replace them." In addition, an Agency
letter of interpretation to Neoterik Health Technologies, Inc. dated
March 18, 1996 concludes that, "when any OSHA standard requires the
use of HEPA filters[,] then the employer may satisfy
the requirement by choosing to use a P100, N100, or R100 filter
certified under 42 CFR 84, since such filters would exhibit minimum
leakage." Therefore, for over eight years, OSHA has consistently
equated HEPA filters to the high-end filters certified by NIOSH under
42 CFR 84.
OSHA believes that this definition is sufficient to meet the
recommendations of these commenters regarding the need to update the
description of HEPA filters consistent with the NIOSH certification
program, including the need to provide the "clear generic guidance"
requested by one of the commenters (Ex. 9-42). As noted by another
commenter (Ex. 9-37), the definition of HEPA filters contained in the
Respiratory Protection Standard also specifies the filtering criterion
that these filters must meet in terms of particulate size. The
definition recognizes that the N100, R100, and P100 filters meet this
criterion, thereby updating the HEPA definition as recommended by this
commenter.
Contrary to the assertions made by one of the commenters (Ex. 10-
4), the Agency is not breaching its earlier decision to permit the use
of dust-mist-fume respirators (instead of respirators configured with
HEPA filters) when employees are exposed to lead levels that are equal
to or below 0.5 mg/m3. Although this commenter mentioned
that the decision covered N95 respirators as well, N95 respirators were
not even available in 1979 when the Agency published the decision and,
therefore, were never part of the decision. The remarks of the last
commenter (Ex. 18-5) described special testing conditions (using a
heated DEHP aerosol challenge agent) that appeared to degrade specific
types of filters. While this information may be of interest to NIOSH in
determining the efficacy of its filter certification program, it is
unclear how useful this information would be in selecting respirators
for use in workplaces that vary substantially from these specialized
testing conditions.
Substituting N95 Filters for HEPA Filters. A
representative for the 3M Company (3M) argued strongly that OSHA should
require only N95 particulate filters for respirators, noting that OSHA
based the existing requirement to use HEPA filters under some exposure
conditions on NIOSH's outdated filter certification process specified
in 30 CFR 11 (Tr. at 396). The 3M Company then described a WPF study
conducted by Jensen et al. in a steel foundry on employees who
performed a grinding operation involving a heavy work load (i.e., as
shown by high airflow rates through the filters) and exposure to an
iron aerosol. The 3M Company claimed that under these conditions, no
significant difference existed between P95 and P100 particulate filters
used by these employees with regard to the percentage of workplace iron
penetration inside the filter. In addition, they asserted that neither
type of filter permitted any detectable oil mist penetration (Ex. 18-7;
Tr. at 397).
Later in the hearing, when asked about the test conditions under
which NIOSH certifies filter efficiency, the 3M representative stated:
NIOSH's testimony yesterday, which I agree with, is that they've
got a worst case, or close to worst case, testing, and, as they've
stated, * * * they expect performance in the workplace to be better
than that rating. * * * So I believe that in the N95 filter[s],
while you see a difference in their performance in the laboratory,
when they're used against workplace aerosols, there is no
difference. (Tr. at 429.)
In his testimony the previous day, the NIOSH representative made
the following statement:
Well, NIOSH does not accept the premise that efficiency levels
for filters that we test should be considered at higher efficiency
levels. The approval program designates an efficiency level for the
filters, which is well known to be tested with a near-worst case
aerosol. However, this is done so that every workplace does not have
to conduct sizing tests before they selected proper filters in the
workplace. We think that this is a proper way to go, and we also do
not think that assuming particle sizes and greater efficiencies on
the filters is a very wise approach for protecting workers. (Tr. at
121.)
The 3M Company also mentioned that another justification for
substituting N95 filters for N100 filters is that "increased breathing
resistance caused by use of a 100 filter may decrease overall
respirator effectiveness by reducing user comfort and thereby reducing
the time the respirator is worn" (Ex. 18-7).
In its post-hearing comments, NIOSH acknowledged, "It is possible
that a specific NIOSH certified 95-level filter may have filter
penetration less than 5% in a specific workplace. However, this type of
workplace-specific result may not be generalized to all 95-level
filters in all workplace settings"' (Ex. 17-7-1). Later in these
comments it stated, "NIOSH has included rigorous certification tests
to help assure that filter performance in the workplace will be
maintained at least at the certification level even under severe
conditions," and "the NIOSH certification criteria are designed to
assure that filters meet minimum performance requirements. NIOSH does
not certify that they will perform any better than these criteria."
Revising the existing respirator selection requirements for HEPA
filters, or for filters certified by NIOSH as N100, R100, and P100
under 42 CFR part 84, is beyond the scope of the present rulemaking.
Additionally, the commenters did not provide any evidence demonstrating
that 95-level filters would protect employees when used under the
worst-case conditions simulated during the NIOSH certification tests.
However, from the evidence presented here, OSHA believes that NIOSH's
filter certification program provides a substantial margin of
protection to employees who use respirators. In addition, it is unclear
from the study discussed by these commenters whether the results are
applicable to the extreme range of exposure conditions used by NIOSH in
its filter certification testing. Consequently, the Agency believes
that adopting the recommendations made by these commenters may enable
employers to purchase respirators that do not perform at the designated
level of efficiency under extreme workplace exposure conditions,
thereby jeopardizing seriously the health of their employees. Absent
data demonstrating that 95-level filters perform effectively under near
worst-case experienced conditions, OSHA is retaining its existing HEPA
filter requirements.
Mixed-Versus Single-Substance Contaminants. Several
commenters recommended superseding the individualized canister/
cartridge change-out schedules in the substance-specific standards with
the performance-based provisions for developing change-out schedules
described in OSHA's Respiratory Protection Standard. Their rationale
for this recommendation is that schedules developed using the
Respiratory Protection Standard provisions are capable of accommodating
employee exposure to multiple contaminants, while the schedules
provided in the substance-specific standards are limited to a single
atmospheric contaminant. For example, 3M noted that:
[T]he benzene standard requires the cartridges be changed before
the beginning of the next shift. In a refinery, workers may be
exposed to benzene along with [toluene] and [x]ylene. The change
schedule should be based on the exposure to the mixture as required
by 29 CFR 1910.134, not just the benzene, because the mixture may
result in requiring the cartridge to be changed sooner than eight
hours. By following the requirements of 134, a change schedule would
be established resulting in changing the cartridge before loss of service
life, thereby, increasing worker protection. (Tr. at 396.)
The International Safety Equipment Association and Thomas Nelson of
NIHS, Inc., made similar statements (Tr. at 518 and Ex. 18-9). In
further justification, 3M remarked that "[r]espirator program
administrators may not be aware that the cartridge change schedules
contained in the substance specific [standards] may not be protective
if multiple contaminants are present" (Ex. 18-7).
These comments are a variation of the comments cited earlier in
this section that recommended removing the change-out schedules
specified for substance-specific standards and replacing them with the
provisions of 29 CFR 1910.134 governing change-out schedules. This
recommendation involves a major revision to these standards, and,
therefore, is beyond the scope of this rulemaking. However, such a
revision likely is unnecessary because change-out schedules involving
multiple-contaminant exposures would not be covered under the
substance-specific standards. Instead, employers must develop these
change-out schedules for air-purifying respirators not equipped with an
end-of-service-life indicator according to the requirements of the
Respiratory Protection Standard, notably paragraph (d)(3)(iii)(B)(2).
Retaining APF Tables for Lead and Asbestos. Several unions
requested that OSHA retain the revised APF tables in the construction
standards for lead and asbestos. During the hearing, a representative
from the Building Construction Trades Department of the AFL-CIO (BCTD)
stated that union-management training centers "conduct a great deal of
worker training on lead and asbestos," and that "these tables * * *
greatly facilitate the understanding of appropriate respirator
selection" (Tr. at 615). This representative stated further:
It is much more usable for these parties to go directly to the
substance-specific standard with the air-monitoring results and
choose the appropriate type of respirator. If employers had to do
calculations to determine the appropriate type of respirator to
select, that is simply an added barrier to compliance. Additionally,
the tables are of great help when communicating the need for
respirators to employers who may not normally be engaged in lead and
asbestos work. (Tr. at 615.)
The BCTD representative later noted that "[i]t's the idea of
jumping from [the respiratory protection] standard to [the lead/
asbestos construction] standard, that's why we don't want the table
[removed]" (Tr. at 647). The BCTD post-hearing comments expanded on
this testimony, stating, "Calculations to determine appropriate
respirator add [a] barrier to compliance * * *" (Ex. 9-29).
A representative of the Insulators and Asbestos Workers
International ("IAWI") found the tables to be invaluable as a
teaching aid, and added that:
I am asked by all types of people, regulators, legislators,
facility engineers, owners of companies, [and] consultants where to
find the information [about APFs]. I just tell them [to] look in the
tables. * * * The common worker knows where to find this. It is
where it should be. There are no OSHA libraries on the job sites. *
* * I am asked by a lot of people in charge of sites where these
[APFs] are in writing. If it is taken out of the rules, if it is not
written, it will not be adhered to. (Tr. at 623.)
However, this representative later admitted that "[e]very one of
our supervisors gets a copy of an updated [construction] standard,"
and "[h]e gets the 1910.134 [i.e., the Respiratory Protection
Standard]" (Tr. at 645.) Similarly, another commenter remarked that
"[e]mployers covered by [substance-]specific standards are already
required to refer to 29 CFR 1910.134 for most respirator program
elements including fit testing, inspection and cleaning, and program
evaluation," and that "[i]f some employers would not bother to
consult 29 CFR 1910.134 for APFs, these same employers are most likely
not complying with other necessary program elements"(Ex. 18-7).
The Agency believes that employers know they are required to use
the Respiratory Protection Standard. Retaining the APF tables in the
construction standards for lead and asbestos is unlikely to result in
any savings or convenience to employers or other parties because these
tables cannot be used safely and effectively without consulting the
requirements of 29 CFR 1910.134. Even one of the union representatives
recognized this necessity when stating that supervisors must have
access to both the construction standards and the Respiratory
Protection Standard at the job site (Tr. at 646). In addition, OSHA
believes that any respirator selection requirements that are unique to
a substance-specific standard (i.e., not subsumed by this rulemaking
under the Respirator Protection Standard) will remain available for
easy access under the particular standard. In this regard, the Agency
concludes that it is unnecessary to retain the APF tables for the lead
and asbestos standards in the construction standards because the
required APF tables can be assembled readily for training purposes from
the available information in the revised substance-specific standards
and the Respiratory Protection Standard.
Upgrading Respirator Type at Employee Request. At the
hearing, the BCTD representative mentioned that several of the
substance-specific standards required employers to upgrade respirators
when requested to do so by employees. The representative encouraged the
Agency to include such a requirement in current and future substance-
specific standards (Tr. at 616). The IAWI representative commented:
[S]ome of our members, for a variety of reasons, like working in
PAPRs. * * * Some people work in them, feel comfortable in them.
They want them. And it makes them more at ease at doing their work.
* * * It makes the person more productive, cools them down; there's
a variety of reasons. (Tr. at 648.)
When asked how often employers upgrade respirators when doing so is
discretionary, this representative replied, "I wouldn't say it's 100
percent. I'd say a portion of them would allow somebody that activity"
(Tr. at 649).
Placing a burden on employers to upgrade respirators at an
employee's request is beyond the scope of this rulemaking. However, the
Agency recognizes the advantages, as well as disadvantages, to
upgrading a respirator at an employee's request. As it stated in the
preamble to the Respiratory Protection Standard with regard to PAPRs:
OSHA continues to believe that under some circumstances PAPRs
provide superior acceptability. These include situations where
employees wear respirators for full shifts, where employees
frequently readjust their negative pressure respirators to achieve
what they consider a more comfortable or tighter fit, and where the
air flow provided by a PAPR reduces the employee's psychological and
physiological discomfort. However, where ambient temperatures are
extremely high or low, PAPRs are often unacceptable because of the
temperature of the airstream in the facepiece. * * * (63 FR 1201.)
OSHA noted further, "The Agency continues to believe that it is
good industrial hygiene practice to provide a respirator that the
employee considers acceptable" (63 FR 1201). Therefore, employers are
free to upgrade respirators voluntarily at an employee's request when
the employee meets the medical qualifications for using the respirator
and receives the necessary training.
5. Summary of Superseding Actions
The following table summarizes final revisions to the existing
respirator selection provisions of OSHA's substance-specific standards.
Section VIII ("Amendments to Standards") of this rulemaking notice
provides the full, plain-language regulatory text of these final revisions.
Summary of Superseding Actions for Substance-Specific Standards
------------------------------------------------------------------------
Existing provisions Final action
------------------------------------------------------------------------
29 CFR 1910.1001(g)(2)(ii)......... Revise.
.1001(g)(3)........................ Remove Table 1 and revise.
.1001(l)(3)(ii).................... Redesignate Table 2 as Table 1.
.1017(g)(3)(i)..................... Remove table and revise.
.1017(g)(3)(iii)................... Remove.
.1018 (Tables I and II)............ Remove.
.1018(h)(3)(i)..................... Revise.
.1018(h)(3)(ii).................... Remove.
.1018(h)(3)(iii)................... Redesignate as .1018 (h)(3)(ii).
.1025(f)(2)(ii).................... Remove Table II.
.1025(f)(3)(i)..................... Revise.
.1027(g)(3)(i)..................... Remove Table 2 and revise.
.1028(g)(3)(ii).................... Remove Table 1.
.1028(g)(2)(i)..................... Revise.
.1028(g)(3)(i)..................... Revise.
.1029(g)(3)........................ Remove Table I and revise.
.1043(f)(3)(i)..................... Remove Table I and revise.
.1043(f)(3)(ii).................... Revise.
.1044(h)(3)........................ Remove Table 1 and revise.
.1045(h)(2)(i)..................... Revise.
.1045(h)(3)........................ Remove Table I and revise.
.1047(g)(3)........................ Remove Table 1 and revise.
.1048(g)(2)........................ Revise.
.1048(g)(3)........................ Remove Table 1 and revise.
.1050(h)(3)(i)..................... Remove Table 1 and revise.
.1052(g)(3)........................ Remove Table 2 and revise.
29 CFR 1915.1001(h)(2)(i) through Remove Table 1 and revise.
(h)(2)(v).
29 CFR 1926.60(i)(3)(i)............ Remove Table 1 and revise.
.62 (f)(3)(i)...................... Remove Table 1 and revise.
.1101(h)(3)(i) through (h)(3)(iv).. Remove Table 1 and revise.
.1127(g)(3)(i)..................... Remove Table 1 and revise.
------------------------------------------------------------------------
6. Use of Plain Language
In the proposal, OSHA rewrote into plain language the respirator-
selection provisions of the substance-specific standards retained in
this final rule. The Agency received no comments on these proposed
revisions. OSHA believes that using plain language will improve the
uniformity and comprehensibility of these provisions. These
improvements will, in turn, enhance employer compliance with the
provisions and, concomitantly, increase the protection afforded to
employees. The Agency also found that rewriting the respirator-
selection provisions of the existing substance-specific standards into
plain-language provisions did not alter the substantive requirements of
the existing provisions. (The following table lists the plain-language
provisions in the final rule and the corresponding provisions in the
existing standards.) Therefore, OSHA is retaining these plain-language
revisions in the final rule.
Plain-Language Provisions in the Final Rule and Corresponding Provisions
in the Existing Standards
------------------------------------------------------------------------
Plain-language provisions Existing provisions
------------------------------------------------------------------------
Sec. 1910.1001(g)(2)(ii)......... Sec. 1910.1001(g)(2)(ii).
Sec. 1910.1001(g)(3)(i).......... Sec. 1910.1001(g)(3); Table 1.
Sec. 1910.1001(g)(3)(ii)......... Sec. 1910.1001(g)(3); Table 1.
Sec. 1910.1017(g)(3)(i)(B)....... Sec. 1910.1017(g)(3)(i);
undesignated table.
Sec. 1910.1017(g)(3)(i)(C)....... Sec. 1910.1017(g)(3)(i);
undesignated table.
Sec. 1910.1018(h)(3)(i)(B)....... Sec. 1910.1018(h)(3)(i); Table II
(footnote 2).
Sec. 1910.1018(h)(3)(i)(C)....... Sec. 1910.1018(h)(3)(i); Table I
and Table II.
Sec. 1910.1018(h)(3)(i)(D)(1).... Sec. 1910.1018(h)(3)(ii).
Sec. 1910.1018(h)(3)(i)(D)(2).... Sec. 1910.1018(h)(3)(i); Table
II.
Sec. 1910.1025(f)(3)(i)(B)....... Sec. 1910.1025(f)(3)(i); Table II
(footnote 2).
Sec. 1910.1025(f)(3)(i)(C)....... Sec. 1910.1025(f)(3)(i); Table
II.
Sec. 1910.1025(f)(3)(ii)......... Sec. 1910.1025(f)(3)(ii).
Sec. 1910.1027(g)(3)(i)(B)....... Sec. 1910.1027(g)(3)(i)(B); Table
2 (footnote b).
Sec. 1910.1027(g)(3)(i)(C)....... Sec. 1910.1027(g)(3)(i)(B); Table
2.
Sec. 1910.1028(g)(3)(i)(B)....... Sec. 1910.1028(g)(3)(i); Table 1.
Sec. 1910.1028(g)(3)(i)(C)....... Sec. 1910.1028(g)(3)(i); Table 1.
Sec. 1910.1028(g)(3)(i)(D)....... Sec. 1910.1028(g)(3)(i); Table 1
(footnote 1).
Sec. 1910.1029(g)(3)............. Sec. 1910.1029(g)(3); Table I.
Sec. 1910.1043(f)(3)(i)(A)....... Sec. 1910.1043(f)(3)(i); Table I.
[[Page 50184]]
Sec. 1910.1043(f)(3)(i)(B)....... Sec. 1910.1043(f)(3)(i); Table I.
Sec. 1910.1043(f)(3)(ii)......... Sec. 1910.1043(f)(3)(ii).
Sec. 1910.1044(h)(3)(ii)......... Sec. 1910.1044(h)(3); Table 1.
Sec. 1910.1045(h)(3)(ii)......... Sec. 1910.1045(h)(3); Table I.
Sec. 1910.1047(g)(3)(i).......... No provision of the original
ethylene oxide standard contains
this text. However, the only
respirators designated for
selection are either full
facepiece respirators or
respirators with hoods and
helmets. Also, Sec.
1910.1047(g)(4) ("Protective
clothing and equipment") states,
"When employees could have eye or
skin contact with EtO or EtO
solutions, the employer must
select and provide * * *
appropriate protective clothing or
other equipment * * * to protect
any area of the employee's body
that may come in contact with the
EtO or EtO solution * * *."
Sec. 1910.1047(g)(3)(ii)......... Sec. 1910.1047(g)(3); Table 1.
Sec. 1910.1047(g)(3)(iii)........ Sec. 1910.1047(g)(3); Table 1.
Sec. 1910.1048(g)(2)(ii)......... Sec. 1910.1048(g)(2)(ii).
Sec. 1910.1048(g)(3)(i)(B)....... Sec. 1910.1048(g)(3)(i); Table 1.
Sec. 1910.1048(g)(3)(i)(C)....... Sec. 1910.1048(g)(3)(i); Table 1.
Sec. 1910.1048(g)(3)(ii)......... Sec. 1910.1048(g)(3)(i); Table 1
(footnote 2).
Sec. 1910.1048(g)(3)(iii)........ Sec. 1910.1048(g)(3)(ii).
Sec. 1910.1050(h)(3)(i)(B)....... Sec. 1910.1050(h)(3)(i); Table 1.
Sec. 1910.1050(h)(3)(i)(C)....... Sec. 1910.1050(h)(3)(i); Table 1.
Sec. 1910.1050(h)(3)(i)(D)....... Sec. 1910.1050(h)(3)(i); Table 1
(footnote 2).
Sec. 1910.1052(g)(3)(i).......... No provision of the original
methylene chloride standard
contains this text. However, the
only respirators designated for
selection are either full
facepiece respirators or
respirators with hoods and
helmets. Also, Sec.
1910.1052(h)(1) ("Protective work
clothing and equipment") states,
"Where needed to prevent MC-
induced skin and eye irritation,
the employer shall provide clean
protective clothing and equipment
which is resistant to MC * * *."
Sec. 1910.1052(g)(3)(ii)......... Sec. 1910.1052(g)(3); Table 2.
Sec. 1915.1001(h)(2)(i).......... Sec. 1915.1001(h)(2)(i); Table 1.
Sec. 1915.1001(h)(2)(ii)......... Sec. 1915.1001(h)(2)(i); Table 1.
Sec. 1915.1001(h)(2)(iii)........ Sec. 1915.1001(h)(2)(iii)(A).
Sec. 1915.1001(h)(2)(iv)......... Sec. 1915.1001(h)(2)(iv).
Sec. 1915.1001(h)(2)(v).......... Sec. 1915.1001(h)(2)(v).
Sec. 1926.60(i)(3)(i)(B)......... Sec. 1926.60(i)(3)(i); Table 1.
Sec. 1926.60(i)(3)(i)(C)......... Sec. 1926.60(i)(3)(i); Table 1.
Sec. 1926.60(i)(3)(i)(D)......... Sec. 1926.60(i)(3)(i); Table 1
(footnote 2).
Sec. 1926.62(f)(3)(i)(B)......... Sec. 1926.62(f)(3)(i); Table 1
(footnote 2).
Sec. 1926.62(f)(3)(i)(C)......... Sec. 1926.62(f)(3)(i); Table 1.
Sec. 1926.1101(h)(3)(i)(A)....... Sec. 1926.1101(h)(3)(i); Table 1.
Sec. 1926.1101(h)(3)(i)(B)....... Sec. 1926.1101(h)(3)(i); Table 1.
Sec. 1926.1101(h)(3)(ii)......... Sec. 1926.1101(h)(3)(ii).
Sec. 1926.1101(h)(3)(iii)........ Sec. 1926.1101(h)(3)(iii).
Sec. 1926.1101(h)(3)(iv)......... Sec. 1926.1101(h)(3)(iv).
Sec. 1926.1127(g)(3)(i)(B)....... Sec. 1926.1127(g)(3)(i); Table 1
(footnote b).
Sec. 1926.1127(g)(3)(i)(C)....... Sec. 1926.1127(g)(3)(i); Table 1.
------------------------------------------------------------------------
VII. Procedural Determinations
A. Legal Considerations
The purpose of the Occupational Safety and Health Act, 29 U.S.C.
651 et seq. ("the Act") is to "assure so far as possible every
working man and woman in the Nation safe and healthful working
conditions and to preserve our human resources" (29 U.S.C. 651(b)). To
achieve this goal, Congress authorized the Secretary of Labor to
promulgate and enforce occupational safety and health standards (see 29
U.S.C. 654(b) (requiring employers to comply with OSHA standards) and
29 U.S.C. 655(b) (authorizing promulgation of standards pursuant to
notice and comment)).
A safety or health standard is a standard "which requires
conditions, or the adoption or use of one or more practices, means,
methods, operations, or processes, reasonably necessary or appropriate
to provide safe or healthful employment or places of employment." (29
U.S.C. 652(8)). A standard is reasonably necessary or appropriate
within the meaning of Section 652(8) of the Act when it substantially
reduces or eliminates significant risk, and is technologically and
economically feasible, cost effective, consistent with prior Agency
action or supported by a reasoned justification for departing from
prior Agency action, and supported by substantial evidence; it also
must effectuate the Act's purposes better than any national consensus
standard it supersedes (see International Union, UAW v. OSHA (LOTO II),
37 F.3d 665 (DC Cir. 1994; and 58 FR 16612-16616 (March 30, 1993)).
The APFs specified by this final rule are an integral part of
OSHA's Respiratory Protection Standard. This standard ensures that
respirators reduce or eliminate the significant risk to employee health
resulting from exposure to hazardous airborne substances. Accordingly,
employers need the APFs provided in this final rule to select
appropriate respirators for employees use when the employers
must rely on respirators to maintain hazardous substances at safe
levels in the workplace. The APFs in this final rule will help ensure
that the Respiratory Protection Standard achieves the annual health
benefits estimated for that standard (i.e., 932 averted work-related
deaths (best estimate) and 4,046 work-related illnesses (best
estimate)) (see 63 FR 1173).
In this rulemaking, OSHA also is superseding the existing APF
requirements in its substance-specific standards. As noted in section V
of this preamble ("Summary of the Final Economic Analysis and
Regulatory Flexibility Analysis"), the Agency estimates that the final
APFs will reduce significantly employee exposures to the hazardous
airborne substances regulated by these substance-specific standards,
especially asbestos, lead, cotton dust, and arsenic. Consequently,
employees will receive additional protection against the chronic
illnesses resulting from exposure to these hazardous substances,
notably a variety of cancers and cardiovascular diseases.
The Agency believes that a standard is technologically feasible
when the protective measures it requires already exist, can be brought
into existence with available technology, or can be developed using
technology that can reasonably be expected to be available (see
American Textile Mfrs. Institute v. OSHA (Cotton Dust), 452 U.S. 490,
513 (1981); American Iron and Steel Institute v. OSHA (Lead II), 939
F.2d 975, 980 (DC Cir. 1991)). A standard is economically feasible when
industry can absorb or pass on the costs of compliance without
threatening the industry's long-term profitability or competitive
structure (see Cotton Dust, 452 U.S. at 530 n. 55; Lead II, 939 F.2d at
980), and a standard is cost effective when the protective measures it
requires are the least costly of the available alternatives that
achieve the same level of protection (see Cotton Dust, 452 U.S. at 514
n. 32; International Union, UAW v. OSHA (LOTO III), 37 F.3d 665, 668
(DC Cir. 1994)).
All standards must be highly protective (see 58 FR 16612, 16614-15
(March 30, 1993); LOTO III, 37 F.3d at 669). Accordingly, section
8(g)(2) of the Act authorizes OSHA "to prescribe such rules and
regulations as [it] may deem necessary to carry out its
responsibilities under the Act" (see 29 U.S.C. 657(g)(2)). However,
health standards also must meet the "feasibility mandate" of section
6(b)(5) of the OSH Act, 29 U.S.C. 655(b)(5). Section 6(b)(5) of the Act
requires OSHA to select "the most protective standard consistent with
feasibility" needed to reduce significant risk when regulating health
hazards (see Cotton Dust, 452 U.S. at 509). Section 6(b)(5) also
directs OSHA to base health standards on "the best available
evidence," including research, demonstrations, and experiments (see 29
U.S.C. 655(b)(5)). In this regard, OSHA must consider "in addition to
the attainment of the highest degree of health and safety protection *
* * the latest scientific data * * * feasibility and experience gained
under this and other health and safety laws" (Id.). Furthermore,
section 6(b)(5) of the Act specifies that standards must "be expressed
in terms of objective criteria and of the performance desired" (see 29
U.S.C. 655(b)(7)).
The APF and MUC provisions in this final rule are integral
components of an effective respiratory protection program. Respiratory
protection is a supplemental method used by employers to protect
employees against airborne contaminants in workplaces when feasible
engineering controls and work practices are not available, have not yet
been implemented, or are not in themselves sufficient to protect
employee health. Employers also use respiratory protection under
emergency conditions involving, for example, the accidental release of
airborne contaminants. The amendments to OSHA's Respiratory Protection
Standard, and the Agency's substance-specific standards, specified in
this final rule will provide employers with critical information to use
when selecting respirators for employees exposed to airborne
contaminants found in general industry, construction, shipyard,
longshoring, and marine terminal workplaces. Since it is generally
recognized that different types of respiratory protective equipment
provide different degrees of protection against hazardous exposures,
proper respirator selection is of critical importance. Failure to
select the proper respirator for use against exposure to hazardous
substances may result in employees being overexposed to these
substances, thereby resulting in an increased incidence of cancer,
cardiovascular disease, and other illnesses. The APF and MUC provisions
in this final rule will greatly enhance an employer's ability to select
a respirator that will adequately protect employees.
The Agency also developed the provisions of this final rule to be
feasible and cost effective, and is specifying them in terms of
objective criteria and the level of performance desired. In this
regard, section V of this preamble ("Summary of the Final Economic
Analysis and Regulatory Flexibility Screening Analysis") provides the
benefits and costs of the final rule, and describes several other
alternatives as required by section 205 of the Unfunded Mandates Reform
Act of 1995 (2 U.S.C. 1535). Based on this information, OSHA concludes
that the APF and MUC provisions of the final rule constitute the most
cost-effective alternative for meeting its statutory objective of
reducing risk of adverse health effects to the extent feasible.
Several benefits will accrue to respirator users and their
employers from this rulemaking. First, the standard benefits workers by
reducing their exposures to respiratory hazards. Improved respirator
selection augments previous improvements to the Respiratory Protection
Standard, such as better fit-test procedures and improved training,
contributing substantially to greater worker protection. At the time of
the 1998 revisions to the Respiratory Protection Standard, the Agency
estimated that the standard would avert between 843 and 9,282 work-
related injuries and illnesses annually, with a best estimate (expected
value) of 4,046 averted illnesses and injuries annually (63 FR 1173).
In addition, OSHA estimated that the standard would prevent between 351
and 1,626 deaths annually from cancer and many other chronic diseases,
including cardiovascular disease, with a best estimate (expected value)
of 932 averted deaths from these causes. The APFs in this rulemaking
will help ensure that these benefits are achieved, as well as provide
an additional degree of protection. These APFs also will reduce
employee exposures to several Sec. 6(b)(5) chemicals covered by
standards with outdated APF criteria, thereby reducing exposures to
chemicals such as asbestos, lead, cotton dust, and arsenic. While the
Agency did not quantify these benefits, it estimates that 29,655
employees would have a higher degree of respiratory protection under
this APF standard. Of these employees, an estimated 8,384 have exposure
to lead, 7,287 to asbestos, and 3,747 to cotton dust, all substances
with substantial health risks.
In addition to health benefits, OSHA believes other benefits result
from the harmonization of APF specifications, thereby making compliance
with the respirator rule easier for employers. Employers also benefit
from greater administrative ease in proper respirator selection.
Employers no longer have to consult several sources and several OSHA
standards to determine the best choice of respirator, but can make
their choices based on a single, easily found
standard. Some employers who now hire consultants to aid in choosing
the proper respirator should be able to make this choice on their own
with the aid of this rule. In addition to having only one set of
numbers (i.e., APFs) to assist them with respirator selection for
nearly all substances, some employers may be able to streamline their
respirator stock by using one respirator type to meet their respirator
needs instead of several respirator types. The increased ease of
compliance also yields additional health benefits to employees using
respirators.
B. Paperwork Reduction Act
After a thorough analysis of the final provisions, OSHA believes
that these provisions do not add to the existing collection-of-
information (i.e., paperwork) requirements regarding respirator
selection. OSHA determined that its existing Respiratory Protection
Standard at 29 CFR 1910.134 has two provisions that involve APFs and
also impose paperwork requirements on employers. These provisions
require employers to: Include respirator selection in their written
respiratory protection program (29 CFR 1910.134(c)(1)(i)); and inform
employees regarding proper respirator selection (29 CFR 1910.(k)(ii)).
The information on respirator selection addressed by these two
provisions must include a brief discussion of the purpose of APFs, and
how to use them in selecting a respirator that affords an employee
protection from airborne contaminants. The burden imposed by this
requirement remains the same whether employers currently use the APFs
published in the 1987 NIOSH RDL or the ANSI Z88.2-1992 Respiratory
Protection Standard, or implement the final APFs in this rulemaking.
Therefore, the use of APFs in the context of these two existing
respirator selection provisions does not require an additional
paperwork-burden determination because OSHA already accounted for this
burden under its existing Respiratory Protection Standard (see 63 FR
1152-1154; OMB Control Number 1218-0099).
Both OSHA's existing Respiratory Protection Standard and the final
APF provisions require employers to use APFs as part of the respirator
selection process. This process includes obtaining information about
workplace exposure to an airborne contaminant, identifying the exposure
limit (e.g., permissible exposure limit) for the contaminant, using
this information to calculate the required level of protection (i.e.,
the APF), and referring to an APF table to determine which respirator
to select. Admittedly, this process involves the collection and use of
information, but it does not require employers to inform others, either
orally or in writing, about the process they use to select respirators
for individual employees, or the outcomes of this process. By not
requiring employers to communicate this information to others, OSHA
removed this process from the ambit of the Paperwork Reduction Act of
1995 (PRA-95) (44 U.S.C. 3506(c)(2)(A)). In the alternative, even if
PRA-95 applies, the final provisions involve the same information
collection and use requirements with regard to APFs as the existing
standard (see paragraphs (d)(1) and (d)(3)(i) of 29 CFR 1910.134, and
the rationale for the existing APF requirements in the preamble to the
final Respiratory Protection Standard, 63 FR 1163 and 1203-1204).
Accordingly, the paperwork burden imposed by the final standard would
be equivalent to the burden already imposed under the existing
standard.
C. Federalism
The Agency reviewed the final APF provisions according to the most
recent Executive Order on Federalism (Executive Order 13132, 64 FR
43225, August 10, 1999). This Executive Order requires that federal
agencies, to the extent possible, refrain from limiting state policy
options, consult with states before taking actions that restrict their
policy options, and take such actions only when clear constitutional
authority exists and the problem is of national scope. The Executive
Order allows federal agencies to preempt state law only with the
expressed consent of Congress. In such cases, federal agencies must
limit preemption of state law to the extent possible.
Under section 18 of the Occupational Safety and Health Act ("the
Act"), Congress expressly provides OSHA with authority to preempt
state occupational safety and health standards to the extent that the
Agency promulgates a federal standard under section 6 of the Act.
Accordingly, section 18 of the Act authorizes the Agency to preempt
state promulgation and enforcement of requirements dealing with
occupational safety and health issues covered by OSHA standards unless
the state has an OSHA-approved occupational safety and health plan
(i.e., is a state-plan state) (see Gade v. National Solid Wastes
Management Association, 112 S. Ct. 2374 (1992)). Therefore, with
respect to states that do not have OSHA-approved plans, the Agency
concludes that this final rule conforms to the preemption provisions of
the Act. Additionally, section 18 of the Act prohibits states without
approved plans from issuing citations for violations of OSHA standards;
the Agency finds that this final rulemaking does not expand this
limitation.
OSHA asserts that it has authority under Executive Order 13132 to
issue final APF requirements because the problems addressed by these
requirements are national in scope. As noted in section V ("Summary of
the Final Economic Analysis and Regulatory Flexibility Screening
Analysis") of this preamble, hundreds of thousands of employers must
select appropriate respirators for millions of employees. These
employees are exposed to many different types and levels of airborne
contaminants found in general industry (including healthcare),
construction, shipyard, longshoring, and marine terminal workplaces.
Accordingly, OSHA concludes that the requirements in this final rule
will provide all covered employers in every state with critical
information to use when selecting respirators to protect their
employees from the risks of exposure to airborne contaminants. However,
while OSHA drafted the final APF and MUC requirements to protect
employees in every state, section 18(c)(2) of the Act permits state-
plan states to develop their own requirements to deal with any special
workplace problems or conditions, provided these requirements are at
least as effective as the requirements specified by this final rule.
D. State Plans
The 26 states and territories with their own OSHA-approved
occupational safety and health plans must adopt provisions comparable
to the provisions in this final rule within six months after the Agency
publishes the rule. These State-Plan states and territories are:
Alaska, Arizona, California, Hawaii, Indiana, Iowa, Kentucky, Maryland,
Michigan, Minnesota, Nevada, New Mexico, North Carolina, Oregon, Puerto
Rico, South Carolina, Tennessee, Utah, Vermont, Virginia, Washington,
and Wyoming. Connecticut, New Jersey, New York, and the Virgin Islands
have OSHA-approved State Plans that apply to state and local government
employees only. Until a state-plan state promulgates its own comparable
provisions, federal OSHA will provide the state with interim
enforcement assistance, as appropriate.
E. Unfunded Mandates
The Agency reviewed the final APF and MUC provisions according to
the Unfunded Mandates Reform Act of 1995 (UMRA) (2 U.S.C. 1501 et seq.)
and Executive Order 12875. As discussed in
section V ("Summary of the Final Economic Analysis and Regulatory
Flexibility Screening Analysis") of this preamble, OSHA estimates that
compliance with this final rule will require private-sector employers
to expend about $4.6 million each year. However, while this final rule
establishes a federal mandate in the private sector, it is not a
significant regulatory action within the meaning of section 202 of the
UMRA (2 U.S.C. 1532).
OSHA standards do not apply to state and local governments, except
in states that have voluntarily elected to adopt an OSHA-approved state
occupational safety and health plan. Consequently, the provisions of
this final rule do not meet the definition of a "Federal
intergovernmental mandate"(see section 421(5) of the UMRA (2 U.S.C.
658(5)). Therefore, based on a review of the rulemaking record, the
Agency believes that few, if any, of the affected employers are state,
local, and tribal governments. Therefore, the requirements of this
final rule do not impose unfunded mandates on state, local, and tribal
governments.
F. Applicability of Existing Consensus Standards
Section 6(b)(8) of the Occupational Safety and Health Act (29
U.S.C. 655(b)(8)) requires OSHA to explain "why a rule promulgated by
the Secretary differs substantially from an existing national consensus
standard," by publishing "a statement of the reasons why the rule as
adopted will better effectuate the purposes of the Act than the
national consensus standard." Regarding APFs, the American National
Standard Institute (ANSI) issued in 1992 is the only publicly available
consensus standard (i.e., ANSI Z88.2-1992, "Respiratory Protection")
that provided APFs for the various respirators covered by this final
rule (i.e., "the 1992 ANSI APFs") (Ex. 1-50). However, ANSI withdrew
this consensus standard in 2003, and it has yet to officially adopt a
replacement standard.
The Agency relied heavily on the 1992 ANSI APFs in developing this
final standard. Nevertheless, the APFs specified in this final rule
differ in important ways from the 1992 ANSI APFs. For example, the APFs
for full facepiece air-purifying respirators differ substantially
between the two standards. Additionally, the APF of 1,000 for powered
air-purifying respirators with helmets or hoods listed in Table 1 of
this final rule is based on achieving specific test results, while the
1992 ANSI APF for this respirator class is not contingent on any test
results. As noted above in section VI of the preamble to this final
rule ("Summary and Explanation of the Final Standard"), OSHA has
determined that the differences between the APFs specified in this
final rule and the 1992 ANSI APFs will afford employees increased
protection when they are exposed to hazardous airborne contaminants.
Therefore, the Agency did not adopt outright the 1992 ANSI APFs under
this final rule.
In addition to the differences between the APF standards described
in the previous paragraph, use of the 1992 ANSI APFs depends on meeting
six other respirator-selection provisions, several of which differ
substantially from the respirator-selection provisions specified in
OSHA's Respiratory Protection Standard. In this regard, use of the 1992
ANSI APFs is contingent on "the nature of the hazardous operation or
process," "the location of the hazardous area in relation to the
nearest area having respirable air," "the activities of workers in
hazardous areas," and "the physical characteristics and functional
capabilities and limitations of the various types of respirators";
none of these conditions is specified in this manner in the Agency's
Respiratory Protection Standard. Revising OSHA's Respiratory Protection
Standard to accommodate the six respirator-selection provisions that
are an integral part of the 1992 ANSI APFs is beyond the scope of this
rulemaking, which provides additional justification for the Agency not
adopting directly the 1992 ANSI APFs.
Finally, the APFs adopted here represent a clear enforceable
requirement, not merely a recommendation. When employers and employees
can easily determine what respirator is appropriately protective,
compliance is simplified and enhanced.
List of Subjects in 29 CFR Parts 1910, 1915, and 1926
Assigned protection factors, Airborne contaminants, Health,
Occupational safety and health, Respirators, Respirator selection.
Authority and Signature
Edwin G. Foulke, Jr., Assistant Secretary of Labor for Occupational
Safety and Health, U.S. Department of Labor, 200 Constitution Ave.,
NW., Washington, DC 20210, directed the preparation of this notice. The
Agency issues these final sections under the following authorities:
Sections 4, 6(b), 8(c), and 8(g) of the Occupational Safety and Health
Act of 1970 (29 U.S.C. 653, 655, 657); Section 3704 of the Contract
Work Hours and Safety Standards Act (the Construction Safety Act) (40
U.S.C. 3701 et seq.); Section 41, the Longshore and Harbor Worker's
Compensation Act (33 U.S.C. 941); Secretary of Labor's Order No. 5-2002
(67 FR 65008); and 29 CFR part 1911.
Signed at Washington, DC on August 9, 2006.
Edwin G. Foulke, Jr.,
Assistant Secretary of Labor.
VIII. Amendments to Standards
0
For the reasons stated in the preamble of this final rule, the Agency
is amending 29 CFR parts 1910, 1915, and 1926 to read as follows:
PART 1910--[AMENDED]
Subpart I--[Amended]
0
1. Revise the authority citation for subpart I of part 1910 to read as
follows:
Authority: Sections 4, 6, and 8 of the Occupational Safety and
Health Act of 1970 (29 U.S.C. 653, 655, and 657); and Secretary of
Labor's Order No. 12-71 (36 FR 8754), 8-76 (41 FR 25059), 9-83 (48
FR 35736), 1-90 (55 FR 9033), 6-96 (62 FR 111), 3-2000 (62 FR
50017), or 5-2002 (67 FR 65008), as applicable.
Sections 1910.132, 1910.134, and 1910.138 of 29 CFR also issued
under 29 CFR part 1911.
Sections 1910.133, 1910.135, and 1910.136 of 29 CFR also issued
under 29 CFR part 1911 and 5 U.S.C. 553.
0
2. Amend Sec. 1910.134 as follows:
0
a. Add the text of the definitions for "Assigned protection factor
(APF)" and "Maximum use concentration (MUC)" to paragraph (b);
0
b. Add the text of paragraphs (d)(3)(i)(A), including Table 1, and
(d)(3)(i)(B); and
0
c. Revise paragraph (n).
The added and revised text reads as follows:
Sec. 1910.134 Respiratory protection.
* * * * *
(b) * * *
Assigned protection factor (APF) means the workplace level of
respiratory protection that a respirator or class of respirators is
expected to provide to employees when the employer implements a
continuing, effective respiratory protection program as specified by
this section.
* * * * *
Maximum use concentration (MUC) means the maximum atmospheric
concentration of a hazardous substance from which an employee can be
expected to be protected when wearing a respirator, and is determined
by the assigned protection factor of the respirator or class of
respirators and the exposure limit of the hazardous substance. The MUC
can be determined mathematically by multiplying the assigned protection
factor specified for a respirator by the required OSHA permissible exposure
limit, short-term exposure limit, or ceiling limit. When no OSHA exposure
limit is available for a hazardous substance, an employer must
determine an MUC on the basis of relevant available information and
informed professional judgment.
* * * * *
(d) * * *
(3) * * *
(i) * * *
(A) Assigned Protection Factors (APFs). Employers must use the
assigned protection factors listed in Table 1 to select a respirator
that meets or exceeds the required level of employee protection. When
using a combination respirator (e.g., airline respirators with an air-
purifying filter), employers must ensure that the assigned protection
factor is appropriate to the mode of operation in which the respirator
is being used.
Table 1.--Assigned Protection Factors \5\
----------------------------------------------------------------------------------------------------------------
Loose-
Type of respirator \1,\\2\ Quarter Half mask Full Helmet/hood fitting
mask facepiece facepiece
----------------------------------------------------------------------------------------------------------------
1. Air-Purifying Respirator.................... 5 \3\ 10 50 ........... ...........
2. Powered Air-Purifying Respirator (PAPR)..... ........... 50 1,000 \4\ 25/ 25
1,000
3. Supplied-Air Respirator (SAR) or Airline
Respirator
Demand mode....................... ........... 10 50 ........... ...........
Continuous flow mode.............. ........... 50 1,000 \4\ 25/ 25
1,000
Pressure-demand or other positive- ........... 50 1,000 ........... ...........
pressure mode.............................
4. Self-Contained Breathing Apparatus (SCBA)
Demand mode....................... ........... 10 50 50 ...........
Pressure-demand or other positive- ........... ........... 10,000 10,000 ...........
pressure mode (e.g., open/closed circuit).
----------------------------------------------------------------------------------------------------------------
Notes:
\1\ Employers may select respirators assigned for use in higher workplace concentrations of a hazardous
substance for use at lower concentrations of that substance, or when required respirator use is independent of
concentration.
\2\ The assigned protection factors in Table 1 are only effective when the employer implements a continuing,
effective respirator program as required by this section (29 CFR 1910.134), including training, fit testing,
maintenance, and use requirements.
\3\ This APF category includes filtering facepieces, and half masks with elastomeric facepieces.
\4\ The employer must have evidence provided by the respirator manufacturer that testing of these respirators
demonstrates performance at a level of protection of 1,000 or greater to receive an APF of 1,000. This level
of performance can best be demonstrated by performing a WPF or SWPF study or equivalent testing. Absent such
testing, all other PAPRs and SARs with helmets/hoods are to be treated as loose-fitting facepiece respirators,
and receive an APF of 25.
\5\ These APFs do not apply to respirators used solely for escape. For escape respirators used in association
with specific substances covered by 29 CFR 1910 subpart Z, employers must refer to the appropriate substance-
specific standards in that subpart. Escape respirators for other IDLH atmospheres are specified by 29 CFR
1910.134 (d)(2)(ii).
(B) Maximum Use Concentration (MUC). (1) The employer must select a
respirator for employee use that maintains the employee's exposure to
the hazardous substance, when measured outside the respirator, at or
below the MUC.
(2) Employers must not apply MUCs to conditions that are
immediately dangerous to life or health (IDLH); instead, they must use
respirators listed for IDLH conditions in paragraph (d)(2) of this
standard.
(3) When the calculated MUC exceeds the IDLH level for a hazardous
substance, or the performance limits of the cartridge or canister, then
employers must set the maximum MUC at that lower limit.
* * * * *
(n) Effective date. Paragraphs (d)(3)(i)(A) and (d)(3)(i)(B) of
this section become effective November 22, 2006.
* * * * *
Subpart Z--[Amended]
0
3. Revise the authority citation for subpart Z of part 1910 to read as
follows:
Authority: Sections 4, 6, and 8 of the Occupational Safety and
Health Act of 1970 (29 U.S.C. 653, 655, and 657); Secretary of
Labor's Orders 12-71 (36 FR 8754), 8-76 (41 FR 25059), 9-83 (48 FR
35736), 1-90 (55 FR 9033), 6-96 (62 FR 111), or 3-2000 (62 FR
50017); and 29 CFR part 1911.
* * * * *
0
4. Amend Sec. 1910.1001 by:
0
a. Removing Table 1 in paragraph (g)(3);
0
b. Redesignating Table 2 in paragraph (l)(3)(ii) as Table 1;
0
c. Removing the reference to "Table 2" in paragraph (l)(3)(ii) and
adding "Table 1" in its place; and
0
d. Revising paragraphs (g)(2)(ii) and (g)(3).
The revisions read as follows:
Sec. 1910.1001 Asbestos.
* * * * *
(g) * * *
(2) * * *
(ii) Employers must provide an employee with a tight-fitting,
powered air-purifying respirator (PAPR) instead of a negative pressure
respirator selected according to paragraph (g)(3) of this standard when
the employee chooses to use a PAPR and it provides adequate protection
to the employee.
* * * * *
(3) Respirator selection. Employers must:
(i) Select, and provide to employees, the appropriate respirators
specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134; however,
employers must not select or use filtering facepiece respirators for
protection against asbestos fibers.
(ii) Provide HEPA filters for powered and non-powered air-purifying
respirators.
* * * * *
0
5. In Sec. 1910.1017, remove the table in paragraph (g)(3)(i), remove
paragraph (g)(3)(iii), and revise paragraph (g)(3)(i) to read as
follows:
Sec. 1910.1017 Vinyl chloride.
* * * * *
(g) * * *
(3) * * *
(i) Employers must:
(A) Select, and provide to employees, the appropriate respirators
specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134.
(B) Provide an organic vapor cartridge that has a service life of
at least one hour when using a chemical cartridge respirator at vinyl
chloride concentrations up to 10 ppm.
(C) Select a canister that has a service life of at least four
hours when using a powered air-purifying respirator having a hood,
helmet, or full or half facepiece, or a gas mask with a front-or back-
mounted canister, at vinyl chloride concentrations up to 25 ppm.
* * * * *
0
6. In Sec. 1910.1018, remove Tables I and II and paragraph (h)(3)(ii),
redesignate paragraph (h) (3)(iii) as paragraph (h)(3)(ii), and revise
paragraph (h)(3)(i) to read as follows:
Sec. 1910.1018 Inorganic arsenic.
* * * * *
(h) * * *
(3) * * *
(i) Employers must:
(A) Select, and provide to employees, the appropriate respirators
specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134.
(B) Ensure that employees do not use half mask respirators for
protection against arsenic trichloride because it is absorbed rapidly
through the skin.
(C) Provide HEPA filters for powered and non-powered air-purifying
respirators.
(D) Select for employee use:
(1) Air-purifying respirators that have a combination HEPA filter
with an appropriate gas-sorbent cartridge or canister when the
employee's exposure exceeds the permissible exposure level for
inorganic arsenic and the relevant limit for other gases.
(2) Front-or back-mounted gas masks equipped with HEPA filters and
acid gas canisters or any full facepiece supplied-air respirators when
the inorganic arsenic concentration is at or below 500 mg/m\3\; and
half mask air-purifying respirators equipped with HEPA filters and acid
gas cartridges when the inorganic arsenic concentration is at or below
100 [mu]g/m\3\.
* * * * *
0
7. In Sec. 1910.1025, remove Table II in paragraph (f)(2)(ii) and
revise paragraphs (f)(3)(i) and (f)(3)(ii) to read as follows:
Sec. 1910.1025 Lead.
* * * * *
(f) * * *
(3) * * *
(i) Employers must:
(A) Select, and provide to employees, the appropriate respirators
specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134.
(B) Provide employees with full facepiece respirators instead of
half mask respirators for protection against lead aerosols that cause
eye or skin irritation at the use concentrations.
(C) Provide HEPA filters for powered and non-powered air-purifying
respirators.
(ii) Employers must provide employees with a powered air-purifying
respirator (PAPR) instead of a negative pressure respirator selected
according to paragraph (f)(3)(i) of this standard when an employee
chooses to use a PAPR and it provides adequate protection to the
employee as specified by paragraph (f)(3)(i) of this standard.
* * * * *
0
8. In Sec. 1910.1027, remove Table 2 in paragraph (g)(3)(i) and revise
paragraph (g)(3)(i) to read as follows:
Sec. 1910.1027 Cadmium.
* * * * *
(g) * * *
(3) * * *
(i) Employers must:
(A) Select, and provide to employees, the appropriate respirators
specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134.
(B) Provide employees with full facepiece respirators when they
experience eye irritation.
(C) Provide HEPA filters for powered and non-powered air-purifying
respirators.
* * * * *
0
9. In Sec. 1910.1028, remove Table 1 in paragraph (g)(3)(ii) and
revise paragraphs (g)(2)(i) and (g)(3)(i) to read as follows:
Sec. 1910.1028 Benzene.
* * * * *
(g) * * *
(2) * * *
(i) Employers must implement a respiratory protection program in
accordance with 29 CFR 1910.134 (b) through (d) (except (d)(1)(iii)),
and (f) through (m).
* * * * *
(3) * * *
(i) Employers must:
(A) Select, and provide to employees, the appropriate respirators
specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134.
(B) Provide employees with any organic vapor gas mask or any self-
contained breathing apparatus with a full facepiece to use for escape.
(C) Use an organic vapor cartridge or canister with powered and
non-powered air-purifying respirators, and a chin-style canister with
full facepiece gas masks.
(D) Ensure that canisters used with non-powered air-purifying
respirators have a minimum service life of four hours when tested at
150 ppm benzene at a flow rate of 64 liters per minute (LPM), a
temperature of 25 [deg]C, and a relative humidity of 85%; for canisters
used with tight-fitting or loose-fitting powered air-purifying
respirators, the flow rates for testing must be 115 LPM and 170 LPM,
respectively.
* * * * *
0
10. In Sec. 1910.1029, remove Table I in paragraph (g)(3) and revise
paragraph (g)(3) to read as follows:
Sec. 1910.1029 Coke oven emissions.
* * * * *
(g) * * *
(3) Respirator selection. Employers must select, and provide to
employees, the appropriate respirators specified in paragraph
(d)(3)(i)(A) of 29 CFR 1910.134; however, employers may use a filtering
facepiece respirator only when it functions as a filter respirator for
coke oven emissions particulates.
* * * * *
0
11. In Sec. 1910.1043, remove Table I in paragraph (f)(3)(i) and
revise paragraphs (f)(3)(i) and (f)(3)(ii) to read as follows:
Sec. 1910.1043 Cotton dust.
* * * * *
(f) * * *
(3) * * *
(i) Employers must:
(A) Select, and provide to employees, the appropriate respirators
specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134; however,
employers must not select or use filtering facepieces for protection
against cotton dust concentrations greater than five times (5 x) the
PEL.
(B) Provide HEPA filters for powered and non-powered air-purifying
respirators used at cotton dust concentrations greater than ten times
(10 x) the PEL.
(ii) Employers must provide an employee with a powered air-
purifying respirator (PAPR) instead of a non-powered air-purifying
respirator selected according to paragraph (f)(3)(i) of this standard
when the employee chooses to use a PAPR and it provides adequate
protection to the employee as specified by paragraph (f)(3)(i) of this
standard.
* * * * *
0
12. In Sec. 1910.1044, remove Table 1 in paragraph (h)(3) and revise
paragraph (h)(3) to read as follows: Sec. 1910.1044 1,2-Dibromo-3-
chloropropane.
* * * * *
(h) * * *
(3) Respirator selection. Employers must:
(i) Select, and provide to employees, the appropriate atmosphere-
supplying respirator specified in paragraph (d)(3)(i)(A) of 29 CFR
1910.134.
(ii) Provide employees with one of the following respirator options
to use for entry into, or escape from, unknown DBCP concentrations:
(A) A combination respirator that includes a supplied-air
respirator with a full facepiece operated in a pressure-demand or other
positive-pressure or continuous-flow mode, as well as an auxiliary
self-contained breathing apparatus (SCBA) operated in a pressure-demand
or positive-pressure mode.
(B) An SCBA with a full facepiece operated in a pressure-demand or
other positive-pressure mode.
* * * * *
0
13. In Sec. 1910.1045, remove Table I in paragraph (h)(3) and revise
paragraphs (h)(2)(i) and (h)(3) to read as follows:
Sec. 1910.1045 Acrylonitrile.
* * * * *
(h) * * *
(2) * * *
(i) Employers must implement a respiratory protection program in
accordance with 29 CFR 1910.134 (b) through (d) (except (d)(1)(iii)),
and (f) through (m).
* * * * *
(3) Respirator selection. Employers must:
(i) Select, and provide to employees, the appropriate respirators
specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134.
(ii) For escape, provide employees with any organic vapor
respirator or any self-contained breathing apparatus permitted for use
under paragraph (h)(3)(i) of this standard.
* * * * *
0
14. In Sec. 1910.1047, remove Table 1 in paragraph (g)(3) and revise
paragraph (g)(3) to read as follows:
Sec. 1910.1047 Ethylene oxide.
* * * * *
(g) * * *
(3) Respirator selection. Employers must:
(i) Select, and provide to employees, the appropriate respirators
specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134; however,
employers must not select or use half masks of any type because EtO may
cause eye irritation or injury.
(ii) Equip each air-purifying, full facepiece respirator with a
front-or back-mounted canister approved for protection against ethylene
oxide.
(iii) For escape, provide employees with any respirator permitted
for use under paragraphs (g)(3)(i) and (ii) of this standard.
* * * * *
0
15. In Sec. 1910.1048, remove Table 1 in paragraph (g)(3)(i) and
revise paragraphs (g)(2) and (g)(3) to read as follows:
Sec. 1910.1048 Formaldehyde.
* * * * *
(g) * * *
(2) Respirator program. (i) Employers must implement a respiratory
protection program in accordance with 29 CFR 1910.134 (b) through (d)
(except (d)(1)(iii)), and (f) through (m).
(ii) When employees use air-purifying respirators with chemical
cartridges or canisters that do not contain end-of-service-life
indicators approved by the National Institute for Occupational Safety
and Health, employers must replace these cartridges or canisters as
specified by paragraphs (d)(3)(iii)(B)(1) and (B)(2) of 29 CFR
1910.134, or at the end of the workshift, whichever condition occurs
first.
(3) Respirator selection. (i) Employers must:
(A) Select, and provide to employees, the appropriate respirators
specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134.
(B) Equip each air-purifying, full facepiece respirator with a
canister or cartridge approved for protection against formaldehyde.
(C) For escape, provide employees with one of the following
respirator options: A self-contained breathing apparatus operated in
the demand or pressure-demand mode; or a full facepiece respirator
having a chin-style, or a front-or back-mounted industrial-size,
canister or cartridge approved for protection against formaldehyde.
(ii) Employers may substitute an air-purifying, half mask
respirator for an air-purifying, full facepiece respirator when they
equip the half mask respirator with a cartridge approved for protection
against formaldehyde and provide the affected employee with effective
gas-proof goggles.
(iii) Employers must provide employees who have difficulty using
negative pressure respirators with powered air-purifying respirators
permitted for use under paragraph (g)(3)(i)(A) of this standard and
that affords adequate protection against formaldehyde exposures.
* * * * *
0
16. In Sec. 1910.1050, remove Table 1 in paragraph (h)(3)(i) and
revise paragraph (h)(3)(i) to read as follows:
Sec. 1910.1050 Methylenedianiline.
* * * * *
(h) * * *
(3) * * *
(i) Employers must:
(A) Select, and provide to employees, the appropriate respirators
specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134.
(B) Provide HEPA filters for powered and non-powered air-purifying
respirators.
(C) For escape, provide employees with one of the following
respirator options: Any self-contained breathing apparatus with a full
facepiece or hood operated in the positive-pressure or continuous-flow
mode; or a full facepiece air-purifying respirator.
(D) Provide a combination HEPA filter and organic vapor canister or
cartridge with powered or non-powered air-purifying respirators when
MDA is in liquid form or used as part of a process requiring heat.
* * * * *
0
17. In Sec. 1910.1052, remove Table 2 in paragraph (g)(3) and revise
paragraph (g)(3) to read as follows:
Sec. 1910.1052 Methylene chloride.
* * * * *
(g) * * *
(3) Respirator selection. Employers must:
(i) Select, and provide to employees, the appropriate atmosphere-
supplying respirator specified in paragraph (d)(3)(i)(A) of 29 CFR
1910.134; however, employers must not select or use half masks of any
type because MC may cause eye irritation or damage.
(ii) For emergency escape, provide employees with one of the
following respirator options: A self-contained breathing apparatus
operated in the continuous-flow or pressure-demand mode; or a gas mask
with an organic vapor canister.
* * * * *
PART 1915--[AMENDED]
0
18. Revise the authority citation for part 1915 to read as follows:
Authority: Section 41, Longshore and Harbor Workers'
Compensation Act (33 U.S.C. 941); Sections 4, 6, and 8 of the
Occupational Safety and Health Act of 1970 (20 U.S.C. 653, 655, and
687); and Secretary of Labor's Order No. 12-71 (36 FR 8754), 8-76
(41 FR 25059), 9-83 (48 FR 35736), 1-90 (55 FR 9033), 6-96 (62 FR
111), 3-2000 (62 FR 50017), or 5-2002 (67 FR 65008) as applicable.
Sections 1915.120 and 1915.152 of 29 CFR also issued under 29
CFR part 1911.
Subpart Z--[Amended]
0
19. In Sec. 1915.1001, remove Table 1 in paragraph (h)(2)(iii) and
revise paragraph (h)(2) to read as follows:
Sec. 1915.1001 Asbestos.
* * * * *
(h) * * *
(2) Respirator selection. (i) Employers must select, and provide to
employees at no cost, the appropriate respirators specified in
paragraph (d)(3)(i)(A) of 29 CFR 1910.134; however, employers must not
select or use filtering facepiece respirators for use against asbestos
fibers.
(ii) Employers are to provide HEPA filters for powered and non-
powered air-purifying respirators.
(iii) Employers must:
(A) Inform employees that they may require the employer to provide
a tight-fitting, powered air-purifying respirator (PAPR) permitted for
use under paragraph (h)(2)(i) of this standard instead of a negative
pressure respirator.
(B) Provide employees with a tight-fitting PAPR instead of a
negative pressure respirator when the employees choose to use a tight-
fitting PAPR and it provides them with the required protection against
asbestos.
(iv) Employers must provide employees with an air-purifying, half
mask respirator, other than a filtering facepiece respirator, whenever
the employees perform:
(A) Class II or Class III asbestos work for which no negative
exposure assessment is available.
(B) Class III asbestos work involving disturbance of TSI or
surfacing ACM or PACM.
(v) Employers must provide employees with:
(A) A tight-fitting, powered air-purifying respirator or a full
facepiece, supplied-air respirator operated in the pressure-demand mode
and equipped with either HEPA egress cartridges or an auxiliary
positive-pressure, self-contained breathing apparatus (SCBA) whenever
the employees are in a regulated area performing Class I asbestos work
for which a negative exposure assessment is not available and the
exposure assessment indicates that the exposure level will be at or
below 1 f/cc as an 8-hour time-weighted average (TWA).
(B) A full facepiece, supplied-air respirator operated in the
pressure-demand mode and equipped with an auxiliary positive-pressure
SCBA whenever the employees are in a regulated area performing Class I
asbestos work for which a negative exposure assessment is not available
and the exposure assessment indicates that the exposure level will be
above 1 f/cc as an 8-hour TWA.
* * * * *
PART 1926--[AMENDED]
Subpart D--[Amended]
0
20. Revise the authority citation for subpart D of part 1926 to read as
follows:
Authority: Section 3704 of the Contract Work Hours and Safety
Standards Act (40 U.S.C. 3701 et seq.); Sections 4, 6, and 8 of the
Occupational Safety and Health Act of 1970 (29 U.S.C. 653, 655, and
657); Secretary of Labor's Orders 12-71 (36 FR 8754), 8-76 (41 FR
25059), 9-83 (48 FR 35736), 1-90 (55 FR 9033), 6-96 (62 FR 111), 3-
2000 (62 FR 50017), or 5.2002 (67 FR 650008); as applicable; and 29
CFR part 11.
Sections 1926.58, 1926.59, 1926.60, and 1926.65 also issued
under 5 U.S.C. 553 and 29 CFR part 1911.
Section 1926.62 of 29 CFR also issued under section 1031 of the
Housing and Community Development Act of 1992 (42 U.S.C. 4853).
Section 1926.65 of 29 CFR also issued under section 126 of the
Superfund Amendments and Reauthorization Act of 1986, as amended (29
U.S.C. 655 note), and 5 U.S.C. 553.
0
21. In Sec. 1926.60, remove Table 1 and revise paragraph (i)(3)(i) to
read as follows:
Sec. 1926.60 Methylenedianiline.
* * * * *
(i) * * *
(3) * * *
(i) Employers must:
(A) Select, and provide to employees, the appropriate respirators
specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134.
(B) Provide HEPA filters for powered and non-powered air-purifying
respirators.
(C) For escape, provide employees with one of the following
respirator options: Any self-contained breathing apparatus with a full
facepiece or hood operated in the positive-pressure or continuous-flow
mode; or a full facepiece air-purifying respirator.
(D) Provide a combination HEPA filter and organic vapor canister or
cartridge with air-purifying respirators when MDA is in liquid form or
used as part of a process requiring heat.
* * * * *
0
22. In Sec. 1926.62, remove Table 1 in paragraph (f)(3)(ii) and revise
paragraph (f)(3)(i) to read as follows:
Sec. 1926.62 Lead.
* * * * *
(f) * * *
(3) * * *
(i) Employers must:
(A) Select, and provide to employees, the appropriate respirators
specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134.
(B) Provide employees with a full facepiece respirator instead of a
half mask respirator for protection against lead aerosols that may
cause eye or skin irritation at the use concentrations.
(C) Provide HEPA filters for powered and non-powered air-purifying
respirators.
* * * * *
Subpart Z--[Amended]
0
23. Revise the authority citation for subpart Z of part 1926 to read as
follows:
Authority: Section 3704 of the Contract Work Hours and Safety
Standards Act (40 U.S.C. 3701 et seq.); Sections 4, 6, and 8 of the
Occupational Safety and Health Act of 1970 (29 U.S.C. 653, 655,
657); Secretary of Labor's Orders 12-71 (36 FR 8754), 8-76 (41 FR
25059), 9-83 (48 FR 35736), 1-90 (55 FR 9033), 6-96 (62 FR 111), 3-
2000 (62 FR 50017), or 5-2002 (67 FR 65008) as applicable; and 29
CFR part 11.
Section 1926.1102 of 29 CFR not issued under 29 U.S.C. 655 or 29
CFR part 1911; also issued under 5 U.S.C. 553.
0
24. In Sec. 1926.1101, remove Table 1 in paragraph (h)(3)(i) and
revise paragraph (h)(3) to read as follows:
Sec. 1926.1101 Asbestos.
* * * * *
(h) * * *
(3) Respirator selection. (i) Employers must:
(A) Select, and provide to employees, the appropriate respirators
specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134; however,
employers must not select or use filtering facepiece respirators for
use against asbestos fibers.
(B) Provide HEPA filters for powered and non-powered air-purifying
respirators.
(ii) Employers must provide an employee with tight-fitting, powered
air-purifying respirator (PAPR) instead of a negative pressure
respirator selected according to paragraph (h)(3)(i)(A) of this
standard when the employee chooses to use a PAPR and it provides
adequate protection to the employee.
(iii) Employers must provide employees with an air-purifying half
mask respirator, other than a filtering facepiece respirator, whenever
the employees perform:
(A) Class II or Class III asbestos work for which no negative
exposure assessment is available.
(B) Class III asbestos work involving disturbance of TSI or
surfacing ACM or PACM.
(iv) Employers must provide employees with:
(A) A tight-fitting powered air-purifying respirator or a full
facepiece, supplied-air respirator operated in the pressure-demand mode
and equipped with either HEPA egress cartridges or an auxiliary
positive-pressure, self-contained breathing apparatus (SCBA) whenever
the employees are in a regulated area performing Class I asbestos work
for which a negative exposure assessment is not available and the
exposure assessment indicates that the exposure level will be at or
below 1 f/cc as an 8-hour time-weighted average (TWA).
(B) A full facepiece supplied-air respirator operated in the
pressure-demand mode and equipped with an auxiliary positive-pressure
SCBA whenever the employees are in a regulated area performing Class I
asbestos work for which a negative exposure assessment is not available
and the exposure assessment indicates that the exposure level will be
above 1 f/cc as an 8-hour TWA.
* * * * *
0
25. In Sec. 1926.1127, remove Table 1 in paragraph (g)(3)(i) and
revise paragraph (g)(3)(i) to read as follows:
Sec. 1926.1127 Cadmium.
* * * * *
(g) * * *
(3) * * *
(i) Employers must:
(A) Select, and provide to employees, the appropriate respirators
specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134.
(B) Provide employees with full facepiece respirators when they
experience eye irritation.
(C) Provide HEPA filters for powered and non-powered air-purifying
respirators.
* * * * *
[FR Doc. 06-6942 Filed 8-23-06; 8:45 am]
BILLING CODE 4510-26-P
