[Federal Register Volume 79, Number 197 (Friday, October 10, 2014)][Proposed Rules][Pages 61383-61438]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2014-24009]


Vol. 79

Friday,

No. 197

October 10, 2014

Part II





Department of Labor





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 Occupational Safety and Health Administration





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29 CFR Parts 1910, 1915, 1917, et al.





 Chemical Management and Permissible Exposure Limits (PELs); Proposed
Rule

Federal Register / Vol. 79 , No. 197 / Friday, October 10, 2014 /
Proposed Rules



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DEPARTMENT OF LABOR

Occupational Safety and Health Administration

29 CFR Parts 1910, 1915, 1917, 1918, and 1926

[Docket No. OSHA 2012-0023]
RIN 1218-AC74


Chemical Management and Permissible Exposure Limits (PELs)

AGENCY: Occupational Safety and Health Administration (OSHA), DOL.

ACTION: Request for Information (RFI).

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SUMMARY: OSHA is reviewing its overall approach to managing chemical
exposures in the workplace and seeks stakeholder input about more
effective and efficient approaches that addresses challenges found with
the current regulatory approach. This review involves considering
issues related to updating permissible exposure limits (PELs), as well
as examining other strategies that could be implemented to address
workplace conditions where workers are exposed to chemicals. The notice
details the role of past court decisions on the Agency's current
approach to chemical management for the purpose of informing
stakeholders of the legal framework in which the Agency must operate.
It then describes possible modifications of existing processes, along
with potential new sources of data and alternative approaches the
Agency may consider. The Agency is particularly interested in
information about how it may take advantage of newer approaches, given
its legal requirements. This RFI is concerned primarily with chemicals
that cause adverse health effects from long-term occupational exposure,
and is not related to activities being conducted under Executive Order
13650, Improving Chemical Facility Safety and Security.

DATES: Comments must be submitted by the following dates:
    Hard copy: must be submitted (postmarked or sent) by April 8, 2015.
    Electronic transmission or facsimile: must be submitted by April 8,
2015.

ADDRESSES: Comments may be submitted by any of the following methods:
    Electronically: Submit comments electronically at:
www.regulations.gov, which is the Federal eRulemaking Portal. Follow
the instructions online for making electronic submissions.
    Fax: Submissions no longer than 10-pages (including attachments)
may be faxed to the OSHA Docket Office at (202) 693-1648.
    Mail, hand delivery, express mail, or messenger or courier service:
Copies must be submitted in triplicate (3) to the OSHA Docket Office,
Docket No. OSHA-2012-0023, U.S. Department of Labor, Room N-2625, 200
Constitution Avenue NW., Washington, DC 20210. Deliveries (hand,
express mail, messenger, and courier service) are accepted during the
Department of Labor and Docket Office's normal business hours, 8:15
a.m. to 4:45 p.m. (E.T.).
    Instructions: All submissions must include the Agency name and the
OSHA docket number (i.e. OSHA-2012-0023). Submissions, including any
personal information provided, are placed in the public docket without
change and may be made available online at: www.regulations.gov. OSHA
cautions against the inclusion of personally identifiable information
(e.g., social security number, birth dates).
    If you submit scientific or technical studies or other results of
scientific research, OSHA requests that you also provide the following
information where it is available: (1) Identification of the funding
source(s) and sponsoring organization(s) of the research; (2) the
extent to which the research findings were reviewed by a potentially
affected party prior to publication or submission to the docket, and
identification of any such parties; and (3) the nature of any financial
relationships (e.g., consulting agreements, expert witness support, or
research funding) between investigators who conducted the research and
any organization(s) or entities having an interest in the rulemaking.
If you are submitting comments or testimony on the Agency's scientific
and technical analyses, OSHA requests that you disclose: (1) The nature
of any financial relationships you may have with any organization(s) or
entities having an interest in the rulemaking; and (2) the extent to
which your comments or testimony were reviewed by an interested party
prior to its submission. Disclosure of such information is intended to
promote transparency and scientific integrity of data and technical
information submitted to the record. This request is consistent with
Executive Order 13563, issued on January 18, 2011, which instructs
agencies to ensure the objectivity of any scientific and technological
information used to support their regulatory actions. OSHA emphasizes
that all material submitted to the rulemaking record will be considered
by the Agency to develop the final rule and supporting analyses.
    Docket: To read or download submissions or other material in the
docket go to: www.regulations.gov or the OSHA Docket Office at the
address above. All documents in the docket are listed in the index;
however, some information (e.g. copyrighted materials) is not publicly
available to read or download through the Web site. All submissions,
including copyrighted material, are available for inspection and
copying at the OSHA Docket Office.

FOR FURTHER INFORMATION CONTACT: General information and press
inquiries: Mr. Frank Meilinger, Director, Office of Communications, U.
S. Department of Labor, Room N-3647, 200 Constitution Avenue NW.,
Washington, DC 20210, telephone (202) 693-1999; email
meilinger.francis2@dol.gov. Technical information: Ms. Lyn Penniman,
Office of Physical Hazards, OSHA, Room N-3718, 200 Constitution Avenue
NW., Washington, DC 20210, telephone (202) 693-1950; email
penniman.lyn@dol.gov.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Purpose
II. Legal Requirements for OSHA Standards
    A. Significant Risk of a Material Impairment: The Benzene Case
    B. Technological and Economic Feasibility
    C. The Substantial Evidence Test
III. History of OSHA's Efforts To Establish PELs
    A. Adopting the PELs in 1971
    B. The 1989 PELs Update
    C. The 1989 PELs Update is Vacated
    D. Revising OSHA's PELs in the Wake of the Eleventh Circuit
Decision
IV. Reconsideration of Current Rulemaking Processes
    A. Considerations for Risk Assessment Methods
    1. Current Quantitative Risk Assessment Methods Typically Used
by OSHA To Support 6(b) Single Substance Rulemaking
    2. Proposed Tiered Approach to Risk Assessment in Support of
Updating PELs for Chemical Substances
    a. General Description and Rationale of Tiered Approach
    b. Hazard Identification and Dose-Response Analysis in the
Observed Range
    c. Derivation of Low-End Toxicity Exposure (LETE)
    d. Margin of Exposure (MOE) as a Decision Tool for Low Dose
Extrapolation
    e. Extrapolation Below the Observed Range
    3. Chemical Grouping for Risk Assessment
    a. Background on Chemical Grouping
    b. Methods of Gap Analysis and Filling
    i. Read-Across Method
    ii. Trend Analysis
    iii. QSAR
    iv. Threshold of Toxicological Concern
    4. Use of Systems Biology and Other Emerging Test Data in Risk
Assessment
    B. Considerations for Technological Feasibility
    1. Legal Background of Technological Feasibility
    2. Current Methodology of the Technological Feasibility
Requirement
    3. Role of Exposure Modeling in Technological Feasibility
    a. Computational Fluid Dynamics Modeling To Predict Workplace
Exposures
    b. The Potential Role of REACH in Technological Feasibility
    c. Technological Feasibility Analysis With a Focus on Industries
with Highest Exposures
    C. Economic Feasibility for Health Standards
    1. OSHA's Current Approach to Economic Feasibility
    2. Alternative Approaches to Formulating Health Standards that
Might Accelerate the Economic Feasibility Analysis
    3. Alternative Analytical Approaches to Economic Feasibility in
Health Standards
    4. Approaches to Economic Feasibility Analysis for a
Comprehensive PELs Update
V. Recent Developments and Potential Alternative Approaches
    A. Sources of Information About Chemical Hazards
    1. EPA's High Production Volume Chemicals
    2. EPA's CompTox and ToxCast
    3. Production and Use Data Under EPA's Chemical Data Reporting
Rule
    4. Structure-Activity Data for Chemical Grouping
    5. REACH: Registration, Evaluation, Authorization, and
Restriction of Chemicals in the European Union (EU)
    B. Non-OEL Approaches to Chemical Management
    1. Informed Substitution
    2. Hazard Communication and the Globally Harmonized System (GHS)
    3. Health Hazard Banding
    4. Occupational Exposure Bands
    5. Control Banding
    6. Task-based Exposure Assessment and Control Approaches
VI. Authority and Signature
Appendix A: History, Legal Background and Significant Court
Decisions
Appendix B: 1989 PELs Table
List of References by Exhibit Number

List of Acronyms: Request for Information on Chemical Management and
Permissible Exposure Limits

ACGIH American Conference of Governmental Industrial Hygienists
ADI Allowable Daily Intake
AIHA American Industrial Hygiene Association
AISI American Iron and Steel Institute
ANSI American National Standards Institute
APHA American Public Health Association
ATSDR Agency for Toxic Substances Disease Registry
BAuA Federal Institute for Occupational Safety and Health (Germany)
BMD Benchmark Dose
BMDL Benchmark Dose Low
BMR Benchmark Response
CDR Chemical Data Reporting
CFD Computational Fluid Dynamics
COSHH Control of Substances Hazardous to Health (U.K.)
CrVI Hexavalent Chromium
CSTEE Scientific Committee on Toxicity, Ecotoxicity and the
Environment (E.U.)
CT Control Technology
DfE Design for the Environment (EPA)
DHHS Department of Health and Human Services (U.S.)
DMEL Derived Minimal Effect Level
DNEL Derived No Effect Level
DOE Washington Department of Ecology
DOL Department of Labor (U.S.)
ECB European Chemicals Bureau (E.U.)
ECHA European Chemicals Agency (E.U.)
EPA Environmental Protection Agency (U.S.)
ES Exposure Scenario
EU European Union
FDA Food and Drug Administration (U.S.)
GAO Government Accountability Office (U.S.)
GHS Globally Harmonized System for the Classification and Labeling
of Chemicals
HazCom 2012 Revised OSHA Hazard Communication Standard
HCS Hazard Communication Standard (OSHA)
HHE Health Hazard Evaluation (NIOSH)
HPV High Production Volume (EPA)
HPVIS High Production Volume Information System (EPA)
HSE Health and Safety Executive (U.K.)
HTS High Throughput Screening
IFA Federation of Institutions for Statutory Accident Insurance and
Prevention (Germany)
IMIS Integrated Management Information System (OSHA)
IPCS World Health Organization International Programme on Chemical
Safety
IRIS Integrated Risk Information System (EPA)
ISTAS Institute of Work, Environment, and Health (Spain)
ITC Interagency Testing Committee (EPA TSCA)
IUR Inventory Update Reporting
LETE Low-end Toxicity Exposure
LOAEL Lowest Observed Adverse Effect Level
LOD Limit of Detection
LTFE Lowest Technologically Feasible Exposure
MA DEP Massachusetts Department of Environmental Protection
MIBK Methyl isobutyl ketone
MOA Modes of Action
MOE Margin of Exposure
MRL Minimal Risk Level
NAICS North American Industry Classification System
NCGC National Institutes of Health Chemical Genomics Center
NIEHS National Institute of Environmental Health Sciences (U.S.)
NIOSH National Institute for Occupational Safety and Health (U.S.)
NIST National Institute of Standards and Technology (U.S.)
NMCSD Navy Medical Center San Diego
NOAEL No Observed Adverse Effect Level
NOES National Occupational Exposure Survey
NORA National Occupational Research Agenda (NIOSH)
NPRM Notice of Proposed Rulemaking (OSHA)
NRC National Research Council (U.S., private)
NTP National Toxicology Program (U.S.)
OECD Organization for Economic Cooperation and Development (multiple
countries, private)
OEL Occupational Exposure Limit
OPPT Office of Pollution Prevention and Toxics (EPA)
OSHA Occupational Safety and Health Administration
OTA Massachusetts Office of Technical Assistance and Technology
PBT Persistent, Bioaccumulative and Toxic
PBZ Personal Breathing Zone
PCRARM (EPA) Presidential/Congressional Commission on Risk
Assessment and Risk Management
PEL Permissible Exposure Limits
PMN Pre-manufacture Notification (EPA)
PNEC Predicted No Effect Concentration
POD Point of Departure
PPE Personal Protective Equipment
PPM Parts Per Million
QCAT Quick Chemical Assessment Tool (DOE)
QSAR Quantitative Structure-Activity Relationship
REACH Registration, Evaluation, Authorization and Restriction of
Chemicals (E.U.)
REL Recommended Exposure Level
RfC Reference Concentration
RFI Request for Information
SAR Structural Activity Relation
SBREFA Small Business Regulatory Enforcement Fairness Act (U.S.)
SDS Safety Data Sheet
SEP Special Emphasis Program
SIC Standards Industrial Classification
SIDS Screening Information Data Set (OECD)
STEL Short-term Exposure Limit
TLV Threshold Value Limit (ACGIH)
TSCA Toxic Substances Control Act (EPA)
TTC Threshold of Toxicological Concern
TWA Time-weighted Average
vPvB Very Persistent and Very Bioaccumulative
WEEL Workplace Environmental Exposure Level (AIHA)

I. Purpose

    The purpose of this Request for Information (RFI) is to present
background information and request comment on a number of technical
issues related to aspects of OSHA's rulemaking process for chemical
hazards in the workplace. In particular, the purpose of the RFI is to:
     Review OSHA's current approach to chemical regulation in
its historical context;
     Describe and explore other possible approaches that may be
relevant to future strategies to reduce and control exposure to
chemicals in the workplace; and
     Inform the public and obtain public input on the best
approaches for the Agency to advance the development and implementation
of approaches to reduce or eliminate harmful chemical exposures in the
21st century workplace.
    By all estimates, the number of chemicals found in workplaces today
far exceeds the number which OSHA regulates, and is growing rapidly.
There is no single source recording all chemicals available in
commerce. Through its Chemical Data Reporting Rule, EPA collects
information on chemicals manufactured or imported at a single site at
25,000 pounds or greater; currently this number exceeds 7,674 chemicals
(U.S. EPA, 2013a; Ex. #1)
    The American Chemistry Council estimates that approximately 8,300
chemicals (or about 10 percent of the 87,000 chemicals in the TSCA
inventory) are actually in commerce in significant amounts (Hogue,
2007; Ex. #2). By contrast the European Chemicals Agency database
contains 10,203 unique substances (as of 9/12/2013) (ECHA, 2013; Ex.
#3). Of these, OSHA has occupational exposure limits for only about 470
substances. Most of these are listed as simple limits and appear in
tables (referred to as "Z-tables") in 29 CFR 1910.1000, Air
Contaminants, Subpart Z, Toxic and Hazardous Substances; Ex. #4.
Approximately 30 have been adopted by OSHA as a part of a comprehensive
standard, and include a number of additional requirements such as
regulated areas, air sampling, medical monitoring, and training
However, with few exceptions, OSHA's permissible exposure limits,
(PELs), which specify the amount of a particular chemical substance
allowed in workplace air, have not been updated since they were
established in 1971 under expedited procedures available in the short
period after the OSH Act's adoption (see 29 CFR 1910.1000; Ex. #4,
1915.1000; Ex. #5, and 1926.55; Ex. #6). Yet, in many instances,
scientific evidence has accumulated suggesting that the current limits
are not sufficiently protective. Although OSHA has attempted to update
its PELs, the Agency has not been successful, except through the
promulgation of a relatively few substance-specific health standard
rulemakings (e.g., benzene, cadmium, lead, and asbestos).
    The most significant effort to update the PELs occurred in 1989
when OSHA tried to update many of its outdated PELs and to create new
PELs for other substances in a single rulemaking covering general
industry PELs. After public notice and comment, the Agency published a
general industry rule that lowered PELs for 212 chemicals and added new
PELs for 164 more (54 FR 2332; Ex. #7). Appendix B to this Request for
Information contains the table of PELs from the 1989 Air Contaminants
Final Rule. The table includes both the PELs originally adopted by OSHA
in 1971 and the PELs established under the 1989 final rule. While the
Agency presented analyses of the risks associated with these chemicals,
as well as the analyses of the economic and technological feasibility
of the proposed limits for these chemicals, these analyses were not as
detailed as those OSHA would have prepared for individual rulemakings.
The final rule was challenged by both industry and labor groups. The
1989 PEL update was vacated by the Eleventh Circuit Court of Appeals
because it found that OSHA had not made sufficiently detailed findings
that each new PEL would eliminate significant risk and would be
feasible in each industry in which the chemical was used. (AFL-CIO v.
OSHA, 965 F.2d 962 (11th Cir. 1992) (the Air Contaminants case; Ex.
#8). This decision is discussed further below and in Appendix A.
    Despite these challenges, health professionals and labor and
industry groups have continued to support addressing PELs which may be
outdated and or inconsistent with the best available current science.
The 1989 Air Contaminants rulemaking effort was supported by the
American Industrial Hygiene Association (AIHA), the American Conference
of Governmental Industrial Hygienists (ACGIH), and the American Public
Health Association (APHA), among many other professional organizations
and associations representing both industry and labor. In an October
2012 survey, members of the AIHA identified updating OSHA PELs as their
number one policy priority. The U.S. Chamber of Commerce, in a letter
dated April 8, 2011 to then Deputy Secretary of Labor, Seth Harris,
also supported updating OSHA's PELs.
    Much has changed in the world since the OSH Act was signed in 1970.
However, workers are essentially covered by the same PELs as they were
forty years ago. And while OSHA has been given no new tools or
increased resources to control workplace exposures, it has had to
conduct increasingly complex analyses, which has effectively slowed the
process. The purpose of this RFI is for OSHA to solicit information as
to the best approach(es) for the Agency to help employers and employees
devise and implement risk management strategies to reduce or eliminate
chemical exposures in the 21st century workplace environment. This is
likely to involve a multi-faceted plan that may include changing or
improving OSHA policies and procedures regarding the derivation and
implementation of PELs, as well as pursuing new strategies to improve
chemical management in the workplace. The Agency is publishing this
notice to inform the public of its consideration of these issues, as
well as solicit public input that can be used to inform further
deliberations, and the determination of an appropriate approach.

II. Legal Requirements for OSHA Standards

    In the past, OSHA has received many suggestions for updating its
PELs, but these suggestions often do not take account of the
requirements imposed by the OSH Act, and thus have been of limited
value to OSHA. OSHA is providing an overview of its legal requirements
for setting standards in order to help commenters responding to this
RFI to provide suggestions that can satisfy these requirements. This
section summarizes OSHA's legal requirements, which are discussed in
greater detail in Appendix A. The next section provides an overview of
OSHA's previous attempts to update the PELs.
    Section 6(b) of the OSH Act (Ex. #9) provides OSHA with the
authority to promulgate health standards. It specifies procedures that
OSHA must use to promulgate, modify, or revoke its standards, including
publishing the proposed rule in the Federal Register, providing
interested persons an opportunity to comment, and holding a public
hearing upon request. However, much of the labor and analysis that goes
into the final rule starts before the publication of the proposal.
Section 6(b)(5) of the Act specifies:

    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.

    In general, as this provision has been construed by the courts, any
workplace health standard adopted by OSHA must meet the following
requirements:
    (1) The standard must substantially reduce a significant risk of
material harm.
    (2) Compliance with the standard must be technically feasible. This
means that the protective measures required by the standard currently
exist, can be brought into existence with available technology, or can
be created with technology that can reasonably be developed.
    (3) Compliance with the standard must be economically feasible.
This means that the standard will not threaten the industry's long term
profitability or substantially alter its competitive structure.
    (4) It must reduce risk of adverse health to workers to the extent
feasible.
    (5) The standard must be supported by substantial evidence in the
record, consistent with prior agency practice or is supported by some
justification for departing from that practice.
    The significant risk, economic and technological feasibility, and
substantial evidence requirements are of particular relevance in
setting PELs, and are discussed further below.

A. Significant Risk of a Material Impairment: The Benzene Case

    The significant risk requirement was first articulated in a
plurality decision of the Supreme Court in Industrial Union Department,
AFL-CIO v. American Petroleum Institute, 448 U.S. 607 (1980), commonly
referred to as the Benzene case. The petitioners challenged OSHA's rule
lowering the PEL for benzene from 10 ppm to 1 ppm. In support of the
new PEL, OSHA found that benzene caused leukemia and that the evidence
did not show that there was a safe threshold exposure level below which
no excess leukemia would occur; OSHA chose the new PEL of 1 ppm as the
lowest feasible exposure level. The Benzene Court rejected OSHA's
approach, finding that the OSH Act only required that employers ensure
that their workplaces are safe, that is, that their workers are not
exposed to "significant risk[s] of harm." 448 U.S. at 642 (Ex. #10).
The Court also made it clear that it is OSHA's burden to establish that
a significant risk is present at the current standard before lowering a
PEL, stating that the burden of proof is normally on the proponent.
Thus, the Court held, before promulgating a health standard, OSHA is
required to make a "threshold finding that a place of employment is
unsafe--in the sense that significant risks are present and can be
eliminated or lessened by a change in practices" before it can adopt a
new standard. Id.
    Although the Court declined to establish a set test for determining
whether a workplace is unsafe, it did state that a significant risk was
one that a reasonable person would consider significant and "take
appropriate steps to decrease or eliminate." 448 U.S. at 655. For
example, it said, a one in a 1,000 risk would satisfy the requirement.
However, this example was merely an illustration, not a hard line rule.
The Court made it clear that determining whether a risk was
"significant" was not a "mathematical straitjacket" and did not
require the Agency to calculate the exact probability of harm. Id. The
1 ppm PEL was vacated because OSHA had not made a significant risk
finding at the 10 ppm level.
    Following the Benzene case, OSHA has satisfied the significant risk
requirement by estimating the risk to workers subject to a lifetime of
exposure at various possible exposure levels. These estimates have
typically been based on quantitative risk assessments in which OSHA, as
a general policy, has considered an excess risk of one death per 1000
workers over a 45-year working lifetime as clearly representing a
significant risk. However, the Benzene case does not require OSHA to
use such a benchmark. In the past, OSHA has stated that a lower risk of
death could be considered significant. See, e.g., Preamble to
Formaldehyde Standard, 52 FR 46168, 46234 (suggesting that risk
approaching six in a million could be viewed as significant). (Ex. #11)

B. Technological and Economic Feasibility

    Under section 6(b)(5) of the Act, a standard must protect against
significant risk, "to the extent feasible, and feasibility is
understood to have both technological and economic aspects. A standard
is technologically feasible if "a typical firm will be able to develop
and install engineering and work practice controls that can meet the
PEL in most operations." United Steelworkers v. Marshall, 647 F.2d
1189, 1272 (D.C. Cir. 1981) ("Lead I"; Ex. #12). OSHA must show the
existence of "technology that is either already in use or has been
conceived and is reasonably capable of experimental refinement and
distribution within the standard's deadlines." Id. Where the Agency
presents "substantial evidence that companies acting vigorously and in
good faith can develop the technology," the Agency is not bound to the
technological status quo, and "can require industry to meet PELs never
attained anywhere." Id. at 1264-65.
    Some courts have required OSHA to determine whether a standard is
technologically feasible on an industry-by-industry basis, Color
Pigments Manufacturers Assoc. v. OSHA, 16 F.3d 1157, 1162-63 (11th Cir.
1994; Ex. #13); AFL-CIO v. OSHA, 965, F.2d 962, 981-82 (11th Cir. 1992)
(Air Contaminants; Ex. #8). However, another court has upheld
technological feasibility findings based on the nature of an activity
across many industries rather than on an industry-by-industry basis,
Public Citizen Health Research Group v. United States Department of
Labor, 557 F.3d 165,178-79 (3d Cir. 2009; Ex. #14).
    With respect to economic feasibility, the courts have stated "A
standard is feasible if it does not threaten massive dislocation to . .
. or imperil the existence of the industry." Lead I, 647 F.2d at 1265
(Ex. #12). In order to show this, OSHA should "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." Id. at 1266. However, "[T]he court
probably cannot expect hard and precise estimates of costs.
Nevertheless, the agency must of course provide a reasonable assessment
of the likely range of costs of its standard, and the likely effects of
those costs on the industry." Id.
    While OSHA is not required to show that all companies within an
industry will be able to bear the burden of compliance, at least one
court has held that OSHA is required to show that the rule is
economically feasible on an industry-by-industry basis. Air
Contaminants, 965 F.2d at 982, 986. (Ex. #8)

C. The Substantial Evidence Test

    The "substantial evidence test" is used by the courts to
determine whether OSHA has reached its burden of proof for policy
decisions and factual determinations. "Substantial evidence" is
defined as "such relevant evidence as a reasonable mind might accept
as adequate to support a conclusion." American Textile Mfrs. Inst.,
Inc. v. Donovan, 452 U.S. 490, 522 (1981; Ex. #15) (quoting Universal
Camera Corp. v. NLRB, 340 U.S. 474, 477 (1951); Ex. #16). The
substantial evidence test does not require "scientific certainty"
before promulgating a health standard (AFL-CIO v. American Petroleum
Institute, 448 U.S. 607, 656 (1980); Ex. 10), but the test does require
OSHA to "identify relevant factual evidence, to explain the logic and
the policies underlying any legislative choice, to state candidly any
assumptions on which it relies, and to present its reasons for
rejecting significant contrary evidence and argument." Lead I, 647
F.2d. at 1207. (Ex. #12)

III. History of OSHA's Efforts To Establish PELs

    The history of OSHA's PELs has three stages. First, OSHA adopted
its current PELs in 1971, shortly after coming into existence. Second,
OSHA attempted to update its PELs wholesale in 1989, but that effort
was rejected by the Eleventh Circuit Court of Appeals in 1992. Third,
OSHA has made subsequent, smaller efforts to update certain PELs, but
those efforts have never come to fruition. This history is summarized
below, and discussed in further detail in Appendix A.

A. Adopting the PELs in 1971

    Under section 6(a), OSHA was permitted an initial two-year window
after the passage of the OSH Act to adopt "any national consensus
standard and any established Federal standard" 29 U.S.C 655(6)(a).
OSHA used this authority in 1971 to establish PELs that were adopted
from federal health standards originally set by the Department of Labor
through the Walsh-Healy Act, in which approximately 400 occupational
exposure limits were selected based on ACGIH's 1968 list of Threshold
Limit Values (TLVs). In addition, about 25 additional exposure limits
recommended by the American Standards Association (now called the
American National Standards Institute) (ANSI), were adopted as national
consensus standards.
    These standards were intended to provide initial protections for
workers from what the Congress deemed to be the most dangerous
workplace threats. Congress found it was "essential that such
standards be constantly improved and replaced as new knowledge and
techniques are developed." S. Rep. 91-1282 at 6. (Ex. #17) However,
because OSHA has been unable to update the PELs, they remain frozen at
the levels at which they were initially adopted. OSHA's PELs are also
largely based on acute health effects and do not take into
consideration newer research regarding chronic health effects occurring
at lower occupational exposures.

B. The 1989 PELs Update

    In 1989, OSHA published the Air Contaminants final rule, which
remains the Agency's most significant attempt at updating the PELs (54
FR 2332). (Ex. #7) Unlike typical substance-specific rulemakings, where
OSHA develops a comprehensive standard, the Air Contaminants final rule
was only intended to update existing PELs or to add PELs for substances
within established boundaries. After extensive review of all available
sources of occupational exposure limits (OELs), OSHA selected the
ACGIH's 1987-88 TLVs as the boundaries for identifying the substances
that would be included in the proposed rule. OSHA proposed 212 more
protective PELs and new PELs for 164 substances not previously
regulated. In general, rather than performing a quantitative risk
assessment for each chemical, the agency looked at whether studies
showed excess effects of concern at concentrations lower than allowed
under the existing standard. Where they did, OSHA made a significant
risk finding and either set a PEL (where none existed previously) or
lowered the existing PEL. These new PELs were based on Agency judgment,
taking into account the existing studies and, as appropriate, safety
factors. Safety factors (also called uncertainty factors) are applied
to the lowest level an effect is seen or to a level where no effects
are seen to derive a PEL.
    In order to determine whether the Air Contaminants rule was
feasible, OSHA prepared the regulatory impact analysis. As part of the
analysis, OSHA performed an industry survey as well as site visits. The
survey was the largest survey ever conducted by OSHA and included
responses from 5,700 firms in industries believed to use chemicals
addressed in the scope of the Air Contaminants proposal. (Ex. #18) It
was designed to focus on industry sectors that potentially had the
highest compliance costs, identified through an analysis of existing
exposure data at the four-digit SIC (Standards Industrial
Classification) code level. OSHA analyzed the data collected to
determine whether the updated PELs were both technologically and
economically feasible for each industry sector covered.
    For technological feasibility, OSHA found that "in the
overwhelming majority of situations where air contaminants [were]
encountered by workers, compliance [could] be achieved by applying
known engineering control methods, and work practice improvements." 54
FR at 2789; Ex. #7. For economic feasibility, OSHA assessed the
economic impact of the standard on industry profits at the two-digit
SIC code level, and found the economic impact not to be significant,
and the new standard therefore economically feasible.
    In the Air Contaminants final rule, OSHA summarized the health
evidence for each individual substance, discussed over 2,000 studies,
reviewed and addressed all major comments submitted to the record, and
provided a rationale for each new PEL chosen. OSHA estimated that over
21 million employees were potentially exposed to hazardous substances
in the workplace and over 4.5 million employees were exposed to levels
above the applicable exposure limits. OSHA projected that the final
rule would result in a potential reduction of over 55,000 lost workdays
due to illnesses per year and that annual compliance with this final
rule would prevent an average of 683 fatalities annually from exposures
to hazardous substances.

C. The 1989 PELs Update Is Vacated by the Court of Appeals

    The update to the Air Contaminants standard generally received
widespread support from both industry and labor. However, there was
dissatisfaction on the part of some industry representatives and union
leaders, who brought petitions for review challenging the standard. For
example, some industry petitioners argued that OSHA's use of generic
findings, the inclusion of so many substances in one rulemaking, and
the allegedly insufficient time provided for comment by interested
parties created a record inadequate to support the new set of PELs. In
contrast, the unions challenged the approach used by OSHA to promulgate
the standard and argued that several PELs were not protective enough.
The unions also asserted that OSHA's failure to include any ancillary
provisions, such as exposure monitoring and medical surveillance,
prevented employers from ensuring the exposure limits were not
exceeded, and resulted in less-protective PELs.
    Although only 23 of the 428 PELs were challenged, the court
ultimately decided to vacate the entire rulemaking, finding that "OSHA
[had] not sufficiently explained or supported its threshold
determination that exposure to these substances at previous levels
posed a significant risk of these material health impairments or that
the new standard eliminates or reduces that risk to the extent
feasible." Air Contaminants 965 F.2d at 986-987; Ex. #8
    With respect to significant risk, the court held that OSHA had
failed to "explain why the studies mandated a particular PEL chosen."
Id. at 976. Specifically, the court stated that OSHA failed to quantify
the risk from individual substances and merely provided conclusory
statements that the new PEL would reduce a significant risk
of material health effects." Id. at 975. Further, the court rejected
OSHA's argument that it had relied on safety factors in setting the new
PELs, stating that OSHA had not adequately supported their use. The
court observed that "the difference between the level shown by the
evidence and the final PEL is sometimes substantial." Id. at 978. It
said that OSHA had not indicated "how the existing evidence for
individual substances was inadequate to show the extent of risk for
these factors" and that the agency had "failed to explain the method
by which its safety factors were determined." Id. "OSHA may use
assumptions but only to the extent that those assumptions have some
basis in reputable scientific evidence," the court concluded. Id. at
978-79.
    The Eleventh Circuit court also rejected OSHA's technological
feasibility findings. The Agency had made these findings mainly at the
two-digit SIC level, but also at the three- and four- digit level where
appropriate given the processes involved. The court rejected this
approach, finding that OSHA failed to make industry-specific findings
or identify the specific technologies capable of meeting the proposed
limit in industry-specific operations. Id. at 981. While OSHA had
identified primary air contaminant control methods: Engineering
controls, administrative controls and work practices and personal
protective equipment, the agency, "only provided a general description
of how the generic engineering controls might be used in the given
sector." Id. Though noting that OSHA need only provide evidence
sufficient to justify a "general presumption of feasibility," the
court held that this "does not grant OSHA license to make overbroad
generalities as to feasibility or to group large categories of
industries together without some explanation of why findings for the
group adequately represents the different industries in that group."
Id. at 981-82.
    The court rejected OSHA's economic feasibility findings for similar
reasons. As discussed above, OSHA supported its economic feasibility
findings for the 1989 Air Contaminants rule based primarily on the
results of a survey of over 5700 businesses, summarizing the projected
cost of compliance at the two-digit SIC industry sector level. The
court held that OSHA was required to show that the rule was
economically feasible on an industry-by industry basis, and that OSHA
had not shown that its analyses at the two-digit SIC industry sector
level were appropriate to meet this burden. Id. at 982. "[A]verage
estimates of cost can be extremely misleading in assessing the impact
of particular standards on individual industries" the court said, and
"analyzing the economic impact for an entire sector could conceal
particular industries laboring under special disabilities and likely to
fail as a result of enforcement." Id. While OSHA might "find and
explain that certain impacts and standards do apply to entire sectors
of an industry" if "coupled with a showing that there are no
disproportionately affected industries within the group," OSHA had not
explained why its use of such a "broad grouping was appropriate." Id.
at 982 n.28, 983.

D. Revising OSHA's PELs in the Wake of the Eleventh Circuit Decision

    In the wake of the Eleventh Circuit's decision, OSHA has generally
pursued a conservative course in satisfying its judicially imposed
analytical burdens. The set of resulting analytical approaches OSHA has
engaged in is highly resource-intensive and has constrained OSHA's
ability to prioritize its regulatory efforts based on risk of harm to
workers. In 1995, OSHA made its first attempt following the Air
Contaminants ruling to update a smaller number of PELs using a more
rigorous analysis of risk, workplace exposures, and technological and
economic feasibility. (Ex. #20) OSHA and the National Institute for
Occupational Safety and Health (NIOSH) conducted preliminary research
on health risks associated with exposure and extent of occupational
exposure. Sixty priority substances were identified for further
examination and twenty of the sixty substances were selected to form a
priority list. Early in 1996, the Agency announced its plans for a
stakeholder meeting, and identified the twenty priority substances, as
well as several risk-related discussion topics. (Ex. #21) During the
meeting, almost all stakeholders from industry and labor agreed that
the PELs needed to be updated; however, not one group completely
supported OSHA's suggested approach. Overall, many of the stakeholders
did not support the development of a list of priority chemicals
targeted for potential regulation and felt there was a lack of
transparency in the process for selecting the initial chemicals.
    In response to stakeholder input and OSHA's research, the agency
selected seven of the 20 substances discussed at the stakeholder
meeting for detailed analysis of risks and feasibility. The chemicals
selected were: (i) Glutaraldehyde, (ii) carbon disulfide, (iii)
hydrazine, (iv) perchloroethylene, (v) manganese, (vi) trimellitic
anhydride, and (vii) chloroprene. Quantitative risk assessments were
performed in-house, and research (including site visits) was undertaken
to collect detailed data on uses, worker exposures, exposure control
technology effectiveness, and economic characteristics of affected
industries.
    The research and analysis were carried out over several years,
after which OSHA decided not to proceed with rulemaking. (Ex. #22) This
decision was influenced by findings that (i) prevalence and intensity
of worker exposures for some of the substances (e.g., carbon disulfide
and hydrazine) had declined substantially since the 1989 rule was
promulgated; (ii) industry had voluntarily implemented controls to
reduce the exposure to safe levels; and (iii) for others, substantial
Agency resources would have been required to fully assess technological
and economic impacts.
    In 1997, OSHA held another meeting with industry and labor on the
proposed PEL development process. Although the project did not result
in a rulemaking to revise the PELs, OSHA gained valuable experience in
developing useful approaches for quantifying non-cancer health risks
through collaboration with external reviewers in scientific peer
reviews of its risk analyses. OSHA is now examining ways to better
address chemical exposures given current resource constraints and
regulatory limitations.
    For readers who are interested in a more detailed account of the
legislation and court decisions that shaped OSHA's current regulatory
framework, Appendix A to this Request for Information, History, Legal
Background and Significant Court Decisions, provides additional
information. Readers may want to consult Appendix A as they frame
responses to the questions posed in this Request for Information.

IV. Reconsideration of Current Rulemaking Processes

    As reviewed in Section II (Legal Requirements for OSHA Standards)
and Section III (History of OSHA's Efforts to Establish PELs), OSHA has
to use the best available evidence to make findings of significant
risk, substantial reductions in risk, and technological and economic
feasibility under the Act. This section reviews how interpretation of
6(b)(5) and subsequent case law has resulted in the methods it uses
when developing risk, technical feasibility, and economic findings as
well as the evidence OSHA has used in the past to make these findings
(i.e., OSHA's use of formal risk assessment modeling to evaluate
significant risk, and the Agency's use of worker exposure data and
exposure control effectiveness data to evaluate technical feasibility
and costs of compliance).
    This section also reviews developments in science and technology
and how these new advancements may improve the scientific basis for
making findings of significant risk, technical feasibility, and
economic feasibility. As an example, the National Academies of Science
has released extensive reviews of advances in science, toxicology, and
risk and exposure assessment and evaluated how the Federal government
can potentially utilize these advancements in its decision-making
processes (NRC, 2012; Ex. #23, NRC, 2009; Ex. #24, NRC, 2007; Ex. #25).
While new technologies will advance the public's understanding in these
critical areas, the Agency has obligations under the OSH Act to make
certain findings under 6(b)(5), as discussed above in Section III. How
OSHA might utilize these new developments to meet the Agency's
evidentiary burden will be discussed in this section.

A. Considerations for Risk Assessment Methods

1. Current Quantitative Risk Assessment Methods Typically Used by OSHA
To Support 6(b) Single Substance Rulemaking
    As discussed in Section III, the Supreme Court requires OSHA to
determine that a significant risk exists before adopting an
occupational safety and health standard. While the Court did not
stipulate a means to distinguish significant from insignificant risks,
it broadly described the range of risks OSHA might determine to be
significant:

    It is the Agency's responsibility to determine in the first
instance what it considers to be a "significant" risk. Some risks
are plainly acceptable and others are plainly unacceptable. If, for
example, the odds are one in a billion that a person will die from
cancer by taking a drink of chlorinated water, the risk clearly
could not be considered significant. On the other hand, if the odds
are one in a thousand that regular inhalation of gasoline vapors
that are 2 percent benzene will be fatal, a reasonable person might
well consider the risk significant and take the appropriate steps to
decrease or eliminate it. (Benzene, 448 U.S. at 655). (Ex. #10),

    OSHA has interpreted the Court's example to mean that a 1 in 1000
risk of serious illness is significant, and has used this measure to
guide its significance of risk determinations. For example, OSHA's risk
assessment for hexavalent chromium estimated that a 45-year
occupational exposure at the PEL of 5[micro]g/m\3\ would lead to more
than 10 lung cancer cases per 1000 workers exposed. Because this risk
exceeds the value of one case of lung cancer per 1000 exposed workers,
OSHA found it to be significant. The significance of risk
determinations of other rules since the Benzene decision have typically
followed a similar logic.
    Over the three decades since the Benzene decision, OSHA has
gradually built up a highly rigorous approach to derive quantitative
estimates of risk such as those found in the hexavalent chromium
preamble. First, the Agency reviews the available exposure-response
data for a chemical of interest. It evaluates the available data sets
and identifies those best suited for quantitative analysis. Using the
best available data, the Agency then conducts extensive statistical
analyses to develop an exposure-response model that is able to
extrapolate probability of disease at exposures below the observed
data. Once the model is developed, OSHA conducts further analyses to
evaluate the sensitivity of the model to error and uncertainties in the
modeling inputs and approach. The exposure-response model is used to
generate estimates of risk associated with a working lifetime of
occupational exposure to the chemical of interest over a range of PEL
options that often include exposure levels below those considered to be
technologically feasible. The entire risk assessment has always been
subject to peer review, from choice of data set(s) through generation
of lifetime risk estimates.When the proposed rule is released for
comment, it receives additional scrutiny from the scientific community,
stakeholders, and the general public. The Agency uses the feedback of
the peer review panel and public comment at the time of proposal to
further test and develop the risk analysis.
    This model-based approach to risk assessment has a number of
important advantages. The quantitative risk estimates can be easily
compared with the level of 1 in 1000 that the Court cited as an example
of significant risk. Sometimes, the best available data come from
worker or animal populations with exposure levels far above the
technologically feasible levels for which OSHA must evaluate risk, and
a risk model is used to extrapolate from high to low exposures. When
large, high-quality exposure-response data sets are available, a
rigorous quantitative analysis can yield robust and fairly precise risk
estimates to inform public understanding and debate about the health
benefits of a new or revised regulation. However, there are also
drawbacks to the model-based approach, and there are situations where a
modeling analysis may not be necessary or appropriate for OSHA to make
the significance of risk determination to support a new or revised
regulation. Model-based risk analyses tend to require a great deal of
Agency time and resources.
    In some cases, the model-based approach is essential to OSHA's
significant risk determination, because it is not evident prior to a
modeling analysis whether there is significant risk at current and
technologically-feasible exposures. In other cases, however, it may be
evident from the scientific literature or other readily available
evidence that risk at the existing PEL is clearly significant and that
it can be substantially reduced by a more stringent regulation without
the need for quantitative estimates extrapolated from an exposure-
response model. In addition to reducing significant risk of harm, the
OSH Act also directs the Agency to determine that health standards for
toxic chemicals are feasible. At times, it is evident without extensive
analysis that the most stringent PEL feasible can only reduce, not
eliminate, significant risk. In such cases, the value of a model-based
quantitative risk assessment may not warrant the Agency time and
resources that model-based risk assessment requires.
    In situations described above where the PEL may be set at the
lowest feasible level, OSHA believes that it can establish significant
risk more efficiently instead of relying on probabilistic estimates
from dose-response modeling as described above. OSHA is exploring a
number of more flexible, scientifically accepted approaches that may
streamline the risk assessment process and increase the capacity to
address a greater number of chemicals.
    Question IV.A.1: OSHA seeks input on the risk assessment process
described above. When is a model-based analysis necessary or
appropriate to determine significance of risk and to select a new or
revised PEL? When should simpler approaches be employed? Are there
specific approaches OSHA should consider using when a model-based
analysis is not required? To the extent possible, please provide
detailed explanation and examples of situations when a model-based risk
analysis is or is not necessary to determine significance of risk and
to develop a new standard.

2. Proposed Tiered Approach to Risk Assessment in Support of Updating
PELs for Chemical Substances
a. General Description and Rationale of Tiered Approach
    OSHA is considering a tiered process to exposure-response
assessment that may enable the agency to more efficiently make the
significant risk findings needed to establish acceptable PELs for
larger numbers of workplace chemicals. The approach involves three
stages: dose-response analysis in the observed range, margin of
exposure determination, and exposure-response extrapolation (if
needed). The process overlaps with the risk-based methodologies
employed by EPA IRIS, NIOSH, the Agency for Toxic Substances Disease
Registry (ATSDR), the European Union Registration, Evaluation,
Authorization, and Restriction of Chemicals (REACH) program, and other
organizations that recommend chemical toxicity values or exposure
levels protective of human health. The first step is dose-response
analysis in the observed range. During this step, OSHA analyzes
exposures (or doses) and adverse outcomes from human studies or animal
bioassays, particularly at the lower end of the exposure range. This
involves the derivation of a "low-end toxicity exposure" (LETE),
which is discussed further in section IV.A.2.c. below.
    The second step is margin of exposure determination, where LETEs
are compared with the range of possible exposure limits that OSHA
believes to be feasible for the new or proposed standard. Typically,
there is a close and ongoing dialogue between those OSHA technical
staff and management responsible for the risk assessment and their
counterparts responsible for the feasibility analyses as the separate
determinations are being simultaneously developed. Feasibility
analyses, in particular, can take years of research, including site
visits and industry surveys. In many of OSHA's rulemakings, the lowest
feasible PEL can only reduce, not eliminate, significant risk. Thus,
OSHA sets many PELs at the lowest feasible level, and not at a level of
occupational exposure considered to be without significant risk. This
significant risk orientation differs from other Federal Agencies, such
as EPA and ATSDR that set environmental exposure levels determined to
be health protective without consideration of feasibility.
    OSHA is considering using a margin of exposure (MOE) approach to
compare the LETE with the range of feasible exposure limits. If the MOE
indicates the range of feasible exposures is in close proximity to the
exposures where toxicity is observed (i.e., a low MOE) then it may not
be necessary to extrapolate exposure-response below the observed range
in order to establish significant risk. In this situation, OSHA would
set the PEL at the exposure level it determines to be feasible and the
dose-response analysis in the observed range should be sufficient to
support Agency significant risk findings. The PEL is set at the lowest
feasible level, with the understanding that significant risk of adverse
health outcomes remains at the new PEL. In the traditional risk
assessment approach described previously, OSHA uses quantitative
exposure-response modeling to estimate risks below the range of
observed exposure, without regard to whether such exposures are
considered to be technologically feasible. If the lowest
technologically feasible workplace exposures are determined to be far
below the LETE (i.e., a high MOE), an exposure-response model would be
needed to determine significant risk at exposures below the observed
range and to set the appropriate PEL.
    If there is a high MOE, then the Agency would move onto the final
stage of the tiered approach, which is exposure-response extrapolation,
where the dose-response relationship is extrapolated outside the
observed range. Many regulatory agencies, such as EPA, choose to
extrapolate outside the observed range for non-cancer health outcomes
by applying a series of extrapolation factors, also called uncertainty
factors, to an observed low-end toxicity value, referred to as a point
of departure (POD). The POD is very similar to the LETE described
above. The distinction between these toxicity values is discussed later
in the subsection. The extrapolation factors are further explained
below.
    In many instances, EPA does not use the extrapolation factor
approach for cancer effects. Rather, EPA uses dose-response modeling in
the observed range and a linear extrapolation below the observed range
to derive a unit risk (i.e., risk per unit of exposure). As described
previously, OSHA also uses dose-response modeling to extrapolate risk
below the observed range for carcinogens as was done for hexavalent
chromium (71 FR 10174-10221; Ex. #26) and methylene chloride (62 FR
1516-1560; Ex. #27). There is a reasonable body of scientific evidence
that genotoxic carcinogens, and perhaps other carcinogenic modes of
action, display linear, non-threshold behavior at very low dose levels.
OSHA also uses dose-response modeling to extrapolate risk below the
observed range for carcinogens. As mentioned earlier, the Agency
develops appropriate exposure-response models (linear or non-linear)
that best fit the existing data and are consistent with available
information on mode of action. The models can be used to extrapolate
risk associated with a working lifetime at occupational exposures below
the observed range.
    In some situations, the LETE is further adjusted to calculate
worker equivalent exposures and to account for how the chemical is
absorbed, distributed, and metabolized, and interacts with target
tissues in the body. These features and other important issues related
to the tiered approach to exposure-response assessment are discussed
below. OSHA believes that there are a number of potential advantages to
using a tiered risk assessment framework including opportunities to
rely more heavily on peer-reviewed risk assessments already prepared by
other Federal agencies.
b. Hazard Identification and Dose-Response Analysis in the Observed
Range
    Hazard identification is the first step in the Federal risk
assessment framework as laid out by the National Research Council's
'red book' in 1983 (NRC, 1983; Ex. #28). In conducting a hazard
identification, OSHA evaluates individual study quality and determines
the weight of evidence from epidemiological, experimental, and
supporting data. Study quality favors strong methodology,
characterization of exposure during critical periods, adequate sample
size/statistical power, and relevance to the workplace population. OSHA
gives weight to both positive and negative studies according to study
quality when the Agency evaluates the association between chemical
agent and an adverse health effect. OSHA determines causality based on
criteria developed by Bradford Hill (Hill, 1965; Ex. #29, Rothman &
Greenland, 1998; Ex. #30). In its review of the available evidence,
OSHA assesses the chemical's modes of action (MOA) and the key
molecular, biological, pathological, and clinical endpoints that
contribute to the health effects of concern.
    The Mode of Action (MOA) is a sequence of key events and processes
starting with the interaction of the agent with a molecular or cellular
target(s) and proceeding through operational and anatomical changes
that result in an adverse health effect(s) of concern. The key events
are empirically measurable molecular or pathological endpoints and
outcomes in experimental systems. These represent necessary precursor
steps or biologically-based markers along the progression to frank
illness and injury.
    MOA informs selection of appropriate toxicity-related endpoints and
models for dose-response analysis. OSHA then conducts a dose-response
analysis for critical health effects determined to be associated with a
chemical, provided there are suitable data available. Dose-response
analysis requires quantitative measures of both exposure and toxicity-
related endpoints. OSHA gives preference to studies with relevant
occupational routes that display a well-defined dose-related change in
response with adequate power to detect effects at the exposure levels
of interest. The Agency generally prefers high quality epidemiologic
studies for dose-response analysis over experimental animal models,
provided there is adequate exposure information and confounding factors
are appropriately controlled. OSHA may only adopt standards for
exposure to "toxic materials and harmful physical agents" that causes
"material impairment of health and loss of functional capacity even if
such employee has regular exposure to the hazard dealt with by such
standard for the period of his working life." OSH Act Sec.  6(b)(5)
(Ex. #9) Therefore, its dose-response analysis considers those
biological endpoints and health outcomes that can lead to adverse
physiological or clinical harm caused by continued exposure over a
working lifetime. This includes key molecular and cellular biomarkers
established as necessary precursor events along a critical disease
pathway. It is important that the toxicity-related endpoints observed
in experimental animals selected for dose-response analysis have
relevance to humans and are not unique to the test species.
    In the past, OSHA, for the most part, has undertaken an independent
evaluation of the evidence in its identification of hazards and
selection of critical studies and toxicity-related endpoints for dose-
response analysis. However, other Federal agencies use the same risk
assessment framework with similar hazard identification and dose-
response selection procedures. EPA, ATSDR, NIOSH and others have active
risk assessment programs and have recently evaluated many chemicals of
interest to OSHA. These assessments undergo scientific peer review and
are subject to public comment. The Agency is considering ways to reduce
the time and resources needed to independently evaluate the available
study data by placing greater reliance on the efforts of other credible
scientific organizations. Although some organizations use their study
evaluations to support non-occupational risk assessments, OSHA believes
that, in most cases, these evaluations can be adapted to the
occupational context.
    Question IV.A.2: If there is no OSHA PEL for a particular substance
used in your facility, does your company/firm develop and/or use
internal occupational exposure limits (OELs)? If so, what is the basis
and process for establishing the OEL? Do you use an authoritative
source, or do you conduct a risk assessment? If so, what sources and
risk assessment approaches are applied? What criteria do facilities/
firms consider when deciding which authoritative source to use? For
example, is rigorous scientific peer review of the OEL an important
factor? Is transparency of how the OEL was developed important?
    Question IV.A.3: OSHA is considering greater reliance on peer-
reviewed toxicological evaluations by other Federal agencies, such as
NIOSH, EPA, ATSDR, NIEHS and NTP for hazard identification and dose-
response analysis in the observed range. What advantages and
disadvantages would result from this approach and could it be used in
support of the PEL update process?
c. Derivation of Low-End Toxicity Exposure (LETE)
    An important aspect of the dose-response analysis is the
determination of exposures that can result in adverse outcomes of
interest. For most studies, response rates ranging from 1 to 10 percent
represent the low end of the observed range. Epidemiologic studies
generally are larger and can show a lower observed response rate than
animal studies, which typically have fewer test subjects. EPA, ATSDR
and EU REACH also derive an estimated dose at the low end of the
observed range (i.e., LETE) as part of their dose-response assessments.
This dose is referred to as the POD ('point of departure') because it
is used as a starting point for low dose extrapolation or the
application of uncertainty factors as described above to derive
toxicity values. EPA, ATSDR and EU REACH use the POD/extrapolation
factor approach to determine Reference Concentrations (RfC), Minimal
Risk Levels (MRL) and Derived No Effect Levels (DNELs), respectively.
OSHA believes the LETE is an exposure where studies may have
demonstrated significant risk. However, OSHA does not intend to use the
LETE as the point of extrapolation for determining a "safe" exposure
level in the manner used by the aforementioned agencies. OSHA may use
the LETE in calculating an MOE to evaluate the need for low dose
extrapolation as described in the next section.
    Traditionally, either the Lowest Observed Adverse Effect Level
(LOAEL) or No Observed Adverse Effect Levels (NOAEL) has served as
easily obtainable LETE descriptors. More recently, the Benchmark Dose
(BMD) methodology has increasingly been applied to derive an LETE. The
BMD approach uses a standard set of empirical models to determine the
dose associated with a pre-selected benchmark response (BMR) level. An
example is the dose associated with a 10 percent incidence (i.e.,
BMD10) and the statistical lower confidence limit (i.e.,
BMDL10). Selection of an appropriate BMR considers biologic
as well as statistical factors and a lower BMR is typically applied for
clinically serious outcomes (e.g., lung or heart disease) than for less
serious adverse effects (e.g., preclinical loss of neurological or
pulmonary function). In some cases, more sophisticated models can be
used in the LETE determination, based on physiologically-based
toxicokinetics, toxicodynamics, or dosimetry models that relate the
administered dose to a more toxicologically relevant dose metric at a
biological target site, if sufficient data is available and the models
are appropriately validated. This is discussed further below.
    Question IV.A.4: OSHA is considering using the Point of Departure
(POD) (e.g., BMD, LOAEL, NOAEL), commonly employed by other
authoritative organizations for carrying out non-cancer risk
assessments as a suitable descriptor of the Low End Toxicity Exposure
(LETE) level that represents a significant risk of harm. Is this an
appropriate application of the POD by OSHA? Are there other exposure
values that OSHA should consider for its LETE?
    In many situations, the LETE must be adjusted to represent a
typical worker exposure. The most common adjustments are to correct for
the standard occupational exposure conditions of eight hours a day/five
days a week and/or respiratory volume during work activity. OSHA and
NIOSH have used a standard ventilation rate of 10 m\3\ of air per 8-
hour work shift for a typical worker undergoing light physical work
activity.
    Allometric scaling (i.e., BW3/4) is recommended by some
Federal authorities when scaling animal doses to human equivalents to
account for toxicokinetic differences in rates of absorption,
metabolism, and excretion when more specific data is lacking.
Allometric scaling refers to scaling physiological rates and quantities
to mass or volume of one animal species to another animal species. The
relationship is generally dependent on body weight (BW), often in the
form of y=BW[agr] where y is the physiological measure and [alpha]
is the scaling component. Many physiological and biochemical processes
(such as heart rate, basal metabolic rate, and respiration rate have
been found to have a scaling component of 0.75.
    Allometric scaling is most applicable when the toxicologically
relevant dose is a parent compound or stable metabolite whose
absorption rate and clearance from the target site is controlled
primarily by first order processes. Allometric scaling is less well
suited for portal-of-entry effects or when toxicity is a consequence of
a highly reactive compound or metabolite. Portal of entry refers to the
tissue or organ of first contact between the biological system and the
agent. This is nasal, respiratory tract and pulmonary tissues for
inhalation; skin for dermal contact, and mouth and digestive tract for
oral exposure.
    In the case of respiratory tract effects from inhalation, EPA
recommends adjusting inhalation doses based on generic dosimetry
modeling that depends on the form of the chemical (e.g., particle of
gas) and site of toxicity (e.g., portal of entry or systemic) (EPA,
1994; Ex. #31). For example, the human equivalent for a reactive gas
that exerts its toxic effect on the respiratory tract is scaled based
on animal to human differences in ventilation rate and regional surface
area of the respiratory tract. On the other hand, the dosimetry model
adjustment for an insoluble gas that exerts its effect in a tissue
remote from the lung is scaled by species differences in the blood: gas
partition coefficient. The generic dosimetry models can accommodate
specific chemical data, if available. The models are only intended to
account for human-to-animal differences in bioavailability and further
allometric or extrapolation factors may be needed to account for
species differences in metabolic activation and toxicodynamics (i.e.,
target site sensitivity to an equivalent delivered dose).
    Question IV.A.5: Several methodologies have been utilized to adjust
critical study exposures to a worker equivalent under representative
occupational exposure conditions including standard ventilation rates,
allometric scaling, and toxicokinetic modeling. What are reasonable and
acceptable methods to determine worker equivalent exposure
concentrations, especially from studies in animals or other
experimental systems?
    The worker-adjusted LETE that is derived from dose-response
analysis in the observed range should be regarded as a chemical
exposure level that leads to significant risk of harm. In most cases,
the LETE is expected to elicit a toxic response in 1 to 10 percent of
the worker population. This approximates an excess risk of 10 to 100
cases of impairment per 1000 exposed workers over a duration that is
typically less than a 45-year working life. This degree of risk would
exceed the 1 per 1000 probability that OSHA historically regards as a
clearly significant risk.
d. Margin of Exposure (MOE) as a Decision Tool for Low Dose
Extrapolation
    As discussed previously, OSHA's statutory and legal obligations
dictate that PELs be set at the level that eliminates significant risk,
if feasible, or if not, at the lowest feasible level. Therefore, Agency
risk assessments are directed at determining significant risk at these
feasible exposures. Because of the feasibility constraints, low dose
extrapolation is not always needed to make the required risk findings.
The OSHA significant risk orientation differs from other Federal
Agencies, such as EPA and ATSDR. The risk-based EPA RfCs and ATSDR MRLs
are intended as environmental exposure levels determined to be health
protective without consideration of feasibility. NIOSH also develops
workplace exposure limits. These recommended exposure limits (RELs) are
based on risk evaluations using human or animal health effects data.
The exposure levels that can be achieved by engineering controls and
measured by analytical techniques are considered in the development of
RELs, but the recommended levels are often below what OSHA regards as
technologically feasible.
    A MOE approach can assist in determining the need to extrapolate
risk below the observed range. The appropriate MOE for use as a
decision tool for low dose extrapolation is the LETE divided by an
estimate of the lowest technologically feasible exposure (LTFE). A
large MOE (i.e., LETE/LTFE ratio) means the LTFE is considerably below
exposures observed to cause adverse outcomes along a critical toxicity
pathway. This situation would require low-dose risk extrapolation to
determine whether technologically feasible exposures lead to
significant risk. A small MOE means the LTFE estimate is reasonably
close to the observed toxic exposures indicating the LTFE likely leads
to significant risk of harm. In this situation, OSHA would set the PEL
at the exposure level it determines to be feasible and the dose-
response analysis in the observed range should be sufficient to support
Agency significant risk findings.
    There are several factors that OSHA would need to consider in order
to find that the MOE is adequate to avoid low-dose risk extrapolation.
These include the nature of the adverse outcome, the magnitude of the
effect, the methodological designs and experimental models of the
selected studies, the exposure metric associated with the outcome, and
the exposure period over which the outcome was studied. OSHA may regard
a larger MOE as acceptable to avoid the need for low-dose extrapolation
for serious clinical effects than a less serious subclinical outcome. A
larger MOE may also be found acceptable for irreversible health
outcomes that continue to progress with continued exposure and respond
poorly to treatment than reversible health outcomes that do not
progress with further exposure. Health outcomes that relate to
cumulative exposures would tolerate higher MOEs than similar outcomes
unrelated to cumulative exposure, especially in short-term studies. In
some instances, an adverse outcome observed in experimental animals
would tolerate higher MOEs than the same response in a human study that
more closely resembles the occupational situation.
    Other Federal agencies apply the MOE approach as part of the risk
assessment process. EPA has included MOE calculations in risk
characterizations of environmental exposure scenarios to assist in risk
management decisions (EPA, 2005; Ex. #32). The EU has also applied a
very similar Margin of Safety analysis to characterize results of risk
assessment conclusions (ECB, 2003; Ex. #33). In its report on the
appropriate uses of risk assessment and risk management in federal
regulatory programs, the Presidential Commission on Risk Assessment and
Risk Management recommended MOE as an approach that provides a common
metric for comparing health risks across different toxicities and
public health programs (PCRARM, 1997; Ex. #34).
    Question IV.A.6: OSHA is considering a Margin of Exposure approach
that compares the LETE with the Lowest Technologically Feasible
Exposure (LTFE) as a decision tool for low dose extrapolation. Is this
a reasonable means of determining if further low dose extrapolation
methods are needed to meet agency significant risk findings?
What other approaches should be considered?
e. Extrapolation Below the Observed Range
    The last step in the tiered approach is extrapolation of risk below
the observed range. This low-dose extrapolation would only be needed if
the MOE is sufficiently high to warrant further dose-response analysis.
This situation occurs when technologically feasible exposures are far
below the LETE and quantitative estimates of risk could be highly
informative in the determination of significant risk. As described in
subsection A.1, OSHA has historically used probabilistic risk modeling
to quantitatively estimate risks at exposure levels below the observed
range. Depending on the nature of the exposure-response data, the
Agency has relied on a wide range of different models that have
included linear relative risk (e.g., hexavalent chromium/lung cancer),
logistic regression (e.g., cadmium/kidney dysfunction), and
physiologically-based pharmacokinetic (e.g., methylene chloride/cancer)
approaches.
    Probabilistic risk models can require considerable time and
resources to construct, parameterize, and statistically verify against
appropriate study data, especially for a large number of chemical
substances. As mentioned previously, several government authorities
responsible for managing the risk to human populations posed by
hazardous chemicals commonly use the computationally less complex
uncertainty factor approach to extrapolate dose-response below the
observed range. The uncertainty factors account for variability in
response within the human population, uncertainty with regard to the
differences between experimental animals and humans, and uncertainty
associated with various other data inferences made in the assessment.
For each of these considerations, a numerical value is assigned and the
point of departure is divided by the product of all applied uncertainty
factors. The result is an exposure level considered to be without
appreciable risk. OSHA attempted to apply uncertainty factors in the
1989 Air Contaminants Rule to ensure that new PELs were set at levels
that were sufficiently below exposures observed to cause health
effects. The Eleventh Circuit ruled that OSHA had failed to show how
uncertainty factors addressed the extent of risk posed by individual
substances and that similarly, OSHA failed to explain the method it
used to derive the safety factors. Air Contaminants 965 F.2d at 978.(
Ex. #8) Since the court ruling, the uncertainty factor approach has
undergone considerable refinement. The scientific considerations for
applying individual factors have been carefully articulated by EPA and
other scientific authorities in various guidance materials (EPA, 2002;
Ex. #35, IPCS, 2005; Ex. #36, ECHA, 2012a; Ex. #37). For some factors
under certain circumstances, it is being proposed that standard
'default' values can be replaced with 'data-driven' values (EPA, 2011;
Ex. #38). However, the type and magnitude of the uncertainty factor
employed for any individual substance still requires a degree of
scientific judgment. The methodology does not provide quantitative
exposure-specific estimates of risk, such as one in a thousand, that
can readily be compared to the significant risk probabilities discussed
in the Benzene decision.
    The National Research Council's Science and Decisions report
recently advocated a dose-response framework that provides quantitative
risk estimates by applying distributions instead of 'single value'
factors (NRC, 2009; Ex. #24). The critical extrapolation factors, such
as species differences in toxic response at equivalent target doses and
inter-individual variability in the human population are defined by
lognormal distribution with an estimated standard deviation. This
allows the human equivalent LETE to be derived in terms of a median and
statistical lower confidence bound. The distributional nature of the
analysis facilitates extrapolation in terms of a probabilistic
projection of average and upper bound risk at specific exposures, such
as X number of individuals projected to develop disease out of 1000
workers exposed to Z level of a toxic substance within some confidence
level Y. The NRC report describes several different conceptual models
with case examples and extrapolation factor distribution calculations
(NRC, 2009; Ex. #24).
    Question IV.A.7: Can the uncertainty factor methodology for
extrapolating below the observed range for non-cancer effects be
successfully adapted by OSHA to streamline its risk assessment process
for the purpose of setting updated PELs? Why or why not? Are there
advantages and disadvantages to applying extrapolation factor
distributions rather than single uncertainty factor values? Please
explain your reasoning.
3. Chemical Grouping for Risk Assessment
    OSHA is also considering the use of one or more chemical grouping
approaches to expedite the risk assessment process. In certain cases,
it may be appropriate to extrapolate data about one chemical across a
group or category of similar chemicals. These approaches are discussed
below.
a. Background on Chemical Grouping
    The term 'grouping' or 'chemical grouping' describes the general
approach to assessing more than one chemical at the same time. It can
include formation of a chemical category or identification of a
chemical analogue (OECD, 2007; Ex. #39). Chemical categories or
analogues can be based on the structural relationship between the
chemicals being grouped.
    Structure-activity relationships (SAR) are relationships between a
compound's chemical structure and physicochemical properties and its
biological effects (e.g., cancer) on living systems. Structurally
diverse chemicals can sometimes be grouped for risk analysis based on a
common mechanism/mode of action or metabolic activation pathway (i.e.,
mechanism/mode of action clustering). Endpoint information for one
chemical is used to predict the same endpoint for another chemical,
which is considered to be "similar" in some way (usually on the basis
of structural similarity and similar properties and/or activities).
    A chemical category is a group of chemicals whose physical-
chemical, human health, environmental, toxicological, and/or
environmental fate properties are likely to be similar or follow a
regular pattern as a result of structural similarity, structural
relationship, or other characteristic(s). A chemical category is
selected based on the hypothesis that the properties of a series of
chemicals with common features will show coherent trends in their
physical-chemical properties, and more importantly, in their
toxicological effects (OECD, 2007; Ex. #39).
    The use of a category approach means that it is possible to
identify chemical properties which are common to at least some members
of the category. This approach provides a basis for establishing trends
in properties across that category and extends the measured data (e.g.,
toxicological endpoint) to similar untested chemicals.
    In the category approach, not every chemical in a group needs to
have exposure-response data in order to be evaluated. Rather, the
overall data for the category as a whole must prove adequate to support
a risk assessment.
The overall data set must allow for an assessment of risk for the
compounds and adverse outcomes that lack adequate study. Chemicals may
be grouped for risk assessment based on the following:
     Common functional group (e.g., aldehyde, epoxide, ester,
specific metal ion);
     Common constituents or chemical classes, similar carbon
range numbers;
     Incremental and constant change across the category (e.g.,
a chain-length category);
     The likelihood of common precursors and/or breakdown
products, via physical or biological processes, which result in
structurally similar chemicals (e.g., the metabolic pathway approach of
examining related chemicals such as acid/ester/salt).
    Within a chemical category, data gaps may be filled by read-across,
trend analysis and Quantitative Structure-Activity Relationships
(QSARs) and threshold of toxicological concern. In some cases, an
effect can be present for some but not all members of the category. An
example is the glycol ethers, where the lower carbon chain length
members of the category indicate reproductive toxicity but the higher
carbon chain length members of the category do not. In other cases, the
category may show a consistent trend where the resulting potencies lead
to different classifications (OECD, 2007; Ex. #39).
b. Methods of Gap Analysis and Filling
    As a result of grouping chemicals based on similarities determined
when employing the various techniques as described above, data gap
filling in a chemical category can be carried out by applying one or
more of the following procedures: read-across, trend analysis,
quantitative (Q)SARs and threshold of toxicological concern (TTC).
i. Read-Across Method
    The read-across approach uses endpoint information for one chemical
(the source chemical) to predict the same endpoint for another chemical
(the target chemical), which is considered to be "similar" in some
way (usually on the basis of structural similarity or on the basis of
the same mode or mechanisms of action). Read-across methods have been
used to assess physicochemical properties and toxicity in a qualitative
or quantitative manner. The main application for qualitative read-
across is in hazard identification.
ii. Trend Analysis
    Chemical category members are often related by a trend (e.g.,
increasing, decreasing or constant) for any specific endpoint. The
relationship of the categorical trend could be molecular mass, carbon
chain length, or to some other physicochemical property.
    The observation of a trend (increasing, decreasing or constant) in
the experimental data for a given endpoint across chemicals can be used
as the basis for interpolation and possibly also extrapolation to fill
data gaps for chemicals with little to no data. Interpolation is the
estimation of a value for a member using measured values from other
members on "both sides" of that member within the defined category
spectrum, whereas extrapolation refers to the estimation of a value for
a member that is near or at the category boundary using measured values
from internal category members (OECD, 2007; Ex. #39).
iii. QSAR
    A Quantitative Structure-Activity Relationship (QSAR) is a
quantitative relationship between a numerical measure of chemical
structure, and/or a physicochemical property, and an effect/activity.
QSARs use mathematical calculations to make predictions of effects/
activities that are either on a continuous scale or on a categorical
scale. "Quantitative" refers to the nature of the relationship
between structurally related chemicals, not the endpoint being
predicted. Most often QSARs have been used for determining aquatic
toxicity or genotoxicity but can be used for evaluating other endpoints
as well (OECD, 2007; Ex. #39).
    Question IV.A.8: Are QSAR, read-across, and trend analysis
acceptable methods for developing risk assessments for a category of
chemicals with similar structural alerts (chemical groupings known to
be associated with a particular type of toxic effect, e.g.,
mutagenicity) or other toxicologically-relevant physiochemical
attributes? Why or why not? Are there other suitable approaches?
iv. Threshold of Toxicological Concern (TTC)
    The Threshold of Toxicological Concern (TTC) refers to the
establishment of an exposure level for a group of chemicals below which
there would be no appreciable risk to human health. The original
concept proposed that a low level of exposure with a negligible risk
can be identified for many chemicals, including those of unknown
toxicity, based on knowledge of their chemical structures. The TTC
approach is a form of risk characterization in which uncertainties
arising from the use of data on other compounds are balanced against
the low level of exposure. The approach was initially developed by the
FDA for migration of chemicals from consumer packaging into food
products and used a single threshold value of 1.5[micro]g/day (referred
to as the threshold of regulation).
    The TTC principle extends the concept used in setting acceptable
daily allowable intakes (ADIs) by proposing that a de minimis value can
be identified for chemicals with little to no toxicity data utilizing
information from structurally related chemicals with known toxicities.
    A decision tree can be developed to apply the TTC principle for
risk assessment decisions:

[GRAPHIC] [TIFF OMITTED] TP10OC14.000

    For OSHA purposes the TTC approach could be adapted to develop an
endpoint-specific LETE value for chemicals in a specific category where
little to no toxicity data exist utilizing source chemicals within the
category where toxicity data is available.
4. Use of Systems Biology and Other Emerging Test Data in Risk
Assessment
    Toxicity testing is undergoing transformation from an approach
primarily based on pathological outcomes in experimental animal studies
to a more predictive paradigm that characterizes critical molecular/
cellular perturbations in toxicity pathways using in vitro test
systems. The paradigm shift is being largely driven by the
technological advances in molecular systems biology such as the use of
high throughput screening (HTS) assays, new computational methods to
predict chemical properties, and computer models able to associate
molecular events with a biological response. The vision, strategies,
and frameworks for applying the new toxicity data to risk-based
decision making are laid out in landmark reports by the National
Research Council (NRC, 2009; Ex. #24, NRC, 2007; Ex. #25). A
collaborative Federal initiative known as "Tox21" has been
established between the National Toxicology Program (NTP), the EPA
Office of Research and Development, the NIH Chemical Genomics Center
(NCGC), and the Food and Drug Administration (FDA) to collaborate on
development, validation, and translation of innovative HTS methods to
characterize key steps in toxicity pathways (NTP, 2013; Ex. #40). Tox21
has already screened over a 1000 compounds in more than 50 quantitative
HTS assays that have been made available to the scientific community
through publically accessible databases (e.g., EPA ACToR, NTP CEBS).
EPA has launched a program, known as "NexGen", to implement the NRC
vision and advance the next generation of risk assessment (EPA, 2013b;
Ex. #41). NexGen is a partnership among EPA, NTP, NCGC, AND FDA, along
with ATSDR and California's EPA Office of Environmental Health Hazard
Assessment. The objectives of NexGen are to pilot the new NRC risk
assessment framework, refine existing bioinformatics systems, and
develop specific prototype health risk assessments. These objectives
are expected to be achieved through an iterative development process
that includes discussion with scientists, risk managers, and
stakeholders.
    Question IV.A.9: How should OSHA utilize the new molecular-based
toxicity data, high throughput and computer-based computational
approaches being generated on many workplace chemicals and the updated
NRC risk-based decision making framework to inform future Agency risk
assessments?

B. Considerations for Technological Feasibility

    Before adopting a particular regulatory alternative, the Agency
must demonstrate that it is technologically feasible. As OSHA currently
performs it, a technological feasibility analysis is often one of the
most resource-intensive aspects of the rulemaking process. The Agency must
identify all of the industries that are potentially affected and compile
the available information on current worker exposure and existing controls
for each industry. On occasion, the best information available for
technological feasibility analyses comes from sparse and incomplete data sets.
Rather than rely exclusively on such variable information, OSHA is considering
the use of exposure modeling, such as computational fluid dynamics
(CFD) modeling, for a more complete picture of worker exposures and the
potential effectiveness of different control strategies. Additionally,
OSHA is looking at other sources of information, such as the REACH
initiative from the European Union, that may help the Agency to better
characterize industries or jobs where there is little to no data on
worker exposures and control technologies.
1. Legal Background of Technological Feasibility
    OSHA must demonstrate that a PEL, as well as any ancillary
provisions, to the extend they are being adopted, are feasible. In
general, OSHA determines that a regulatory alternative is
technologically feasible when it has evidence that demonstrates the
alternative is achievable in most operations most of the time. The
Agency must also show that sampling and analytical methods can measure
exposures at the proposed PEL within an acceptable degree of accuracy.
OSHA makes these determinations in the technological feasibility
analysis, which is made available to the public in the OSHA rulemaking
docket.
2. Current Methodology of the Technological Feasibility Requirement
    To develop its technological feasibility analysis, the Agency must
first collect the information about the industries that are affected by
a particular hazard, the sources of exposure, the frequency of the
exposure, the number of workers exposed to various levels, what control
measures or other efforts are being made to reduce exposure to the
hazard, and what sampling and analytical methods are available.
    This information is typically obtained from numerous sources
including:
     Published literature,
     OSHA Special Emphasis Program (SEP) reports,
     NIOSH reports, such as health hazard evaluations (HHE),
control technology (CT) assessments, surveys, recommendations for
exposure control, and engineering control feasibility studies,
     Site visits, conducted by OSHA, NIOSH, or supporting
contractors,
     Information from other stakeholders, such as federal and
state agencies, labor organizations, industry associations, and
consensus standards,
     Unpublished information, such as personal communications,
meetings, and presentations, and
     OSHA Integrated Management Information System (IMIS) data.
    With this information, OSHA creates profiles that identify the
industries where exposures occur, what operations lead to exposures,
and what engineering controls and work practices are being implemented
to mitigate exposures. A technological feasibility analysis is
typically organized by industry sector or group of sectors that
performs a unique activity involving similar activities. OSHA
identifies the operations that lead to exposures in all of these
industries, and eventually determines the feasibility of a PEL by
analyzing whether the PEL can be achieved in most operations most of
the time, as an aggregate across all industries affected. OSHA has also
utilized an application approach that evaluates the feasibility of
controls for a specific type of process used across a number of
industry sectors, such as welding, rather than on an industry-by-
industry basis.
    OSHA develops detailed descriptions of how the substance is used in
different industries, the work activities during which workers are
exposed, and the primary sources of exposure. The Agency also
constructs exposure profiles for each industry, or by job category,
based on operations performed. The Agency classifies workers by job
categories within those industries, based on how similar work processes
are, and to what extent similar engineering controls can be applied to
control exposures in those processes.
    Each exposure profile contains a list of affected job categories,
summary statistics for each job category and subcategories (such as the
mean, median, and range of exposures), and the distribution of worker
exposures using increments based on the regulatory alternatives.
    OSHA's technological feasibility analyses for PEL-setting standards
have traditionally relied on full-shift, personal breathing zone (PBZ)
samples to create exposure profiles. A PBZ sample is the best sample
type to quantify the inhalation exposure of a worker. Area samples are
typically not used to construct exposure profiles but are useful to
characterize how much airborne contamination is present in a work
environment and to evaluate the effectiveness of engineering and other
process control measures.
    Exposure profiles are used to establish the baseline exposure
conditions for every job category in affected industries. Baseline
conditions are developed to allow the Agency to estimate the extent to
which additional controls will be required to achieve a level specified
by a regulatory alternative.
    Next, the technological feasibility analysis describes the
additional controls necessary to achieve the regulatory alternatives.
OSHA relies on its traditional hierarchy of controls when demonstrating
the feasibility of control technology. The traditional hierarchy of
controls includes, in order of preference: Substitution, local exhaust
ventilation, dust suppression, process enclosures, work practices, and
housekeeping. OSHA considers use of personal protective equipment, such
as respirators, to be is the least effective method for controlling
employee exposure, and therefore, personal protective equipment is
considered only for limited situations in which all feasible
engineering controls have been implemented, but do not effectively
reduce exposure to below the permissible exposure limit. To identify
what additional controls are feasible, the Agency conducts a detailed
investigation of the controls used in different industries based
primarily on case studies.
    OSHA develops preliminary conclusions regarding feasibility of
regulatory alternatives, by identifying the lowest levels of exposure
that are technologically feasible in workplaces. To determine whether
an alternative is feasible throughout the spectrum of affected
industries, OSHA studies whether the regulatory alternative is
achievable in most operations most of the time by a typical firm. OSHA
may also determine whether a specific process used across a number of
different industries can be effectively controlled.
3. Role of Exposure Modeling in Technological Feasibility
    In many situations, the Agency has found it difficult to develop
comprehensive exposure profiles and determine additional controls
because of limitations associated with the available exposure data.
These information gaps could be filled by incorporating exposure
modeling into the technological feasibility process. The limitations
associated with the data collected include:
     Limited number of exposure samples: On occasions, an
exposure profile for a job category may be built on a limited number of
full-shift exposure samples, and the Agency has to judge whether the
samples available are representative of the actual exposure distribution
for that industry.
     Limit of Detection (LOD) issues: Because only a few
exposure samples may be available for a job category, the analysis may
include samples reported as "less than" values, high LODs, or
adjusted LOD values. This causes inconsistency in the use of LOD
samples and may cause the Agency to under- or over-estimate the actual
exposure distribution.
     Lack of information on controls associated with data:
Information regarding working conditions and control strategies
associated with exposure samples may not be available. This makes it
difficult for the Agency to determine the impact of the control
strategies for various sources of exposure. Additionally, it is common
that the data does not include information about the exact nature of
the task performed during the sampling period. Sometimes, samples may
not exactly correspond to the job category to which OSHA assigns it in
the analysis because the job activities performed are not adequately
described.
     Limitations of traditional industrial hygiene sampling:
Traditional industrial hygiene practices require a "before and after"
data set to gauge the effectiveness of control strategies implemented,
and changes that occur in the working environment during the sampling
periods. The exact impact of control strategies and environmental
conditions cannot be determined easily with only one set of samples
obtained at a discrete moment in time. It is often the case that OSHA
does not have the luxury of "before and after" data sets and must
determine how the sample set fits into the exposure profile.
     IMIS data limitations: Since the Agency may lack exposure
data for a particular job category or operation, it sometimes relies on
IMIS data. OSHA does not usually rely on IMIS data in its exposure
profiles unless there are no other exposure data available because the
IMIS data can have some significant limitations, which include the
following:
    [cir] Insufficient information to determine if a hazard is present
in the work area in significant amounts as to be relevant for an
exposure profile. For example, an analyst cannot tell from the
information available in the IMIS database if a sample was targeted for
the hazard in question, or if it was part of a larger metal screening
process (if the hazard is a metal), which typically includes up to 16
different metals whether they are thought to be present in the sampling
environment or not.
    [cir] Use of SIC codes in historic IMIS data, which do not
translate directly into the NAICS codes currently used in the analyses.
    [cir] There is no information in the database on the end product
being developed, the action performed to produce it, or the materials
being used when the sample is taken. This limits the interpretation of
the data, since an analyst is not able to attribute the exposure to any
particular practice or process, and cannot recommend engineering
controls.
    Generally, OSHA has had the most success using IMIS data to
identify and collect enforcement case files for further review. Case
files from OSHA inspections contain more detailed information on worker
activities and exposure controls observed at the time an exposure
sample is taken. Thus, use of case files to a large extent mitigates
the limitations of using IMIS data.
    For most health standards, OSHA does not have the resources to
conduct site visits to obtain the necessary exposure information at
firms that are representative of all the affected industries. In an
effort to develop more robust exposure profiles, the Agency is
considering the use of exposure modeling, such as computational fluid
dynamics (CFD) modeling, to complement the exposure information that is
already available from literature, site visits, NIOSH and similar field
investigations, and employer-provided data. This technique would
potentially allow OSHA to better estimate workplace exposures in those
environments were data are limited.
    Question IV.B.1: OSHA described how it obtains information
necessary to conduct its industry profiles. Are there additional or
better sources of information on the industries where exposures are
likely, the numbers of workers and current exposure levels that OSHA
could use?
a. Computational Fluid Dynamics Modeling To Predict Workplace Exposures
    OSHA is considering the use of computational fluid dynamics (CFD)
to model workplace exposure. CFD is a discipline of fluid mechanics
that uses computer modeling to solve complex problems involving fluid
flows. Fluid flow is the physical behavior of fluids, either liquids or
gases, and it is represented by systems of partial differential
equations that describe conservation of energy, mass, and momentum. For
some physical phenomena, such as the laminar flow of a fluid through a
cylindrical pipe, these equations can be solved mathematically. Such
solutions describe how a fluid will move through the specified area, or
geometry, as a function of time. For more complex physical phenomena,
such as turbulent flow of a fluid through a complex geometry, numerical
approaches are used to solve the governing differential equations. As
such, CFD modeling uses mathematical models and numerical methods to
determine how fluids will behave according to a particular set of
variables and parameters. A mathematical model simulates the physical
phenomena under consideration (i.e. governing equations of energy,
mass, and momentum) and, in turn, a numerical method solves that model.
Overall, CFD modeling enables scientists and engineers to perform
computer simulations in order to make better qualitative and
quantitative predictions of fluid flows.
    Some modeling techniques, such as CFD, allow a user to create a
virtual geometry to simulate actual work environments using appropriate
mathematical models and computational methods. The solutions predict
exposures at any given time and in any point in the space of the
geometry established. A model developed with this technique allows the
user to evaluate exposures in a worker's personal breathing zone and
identify areas in the work space that present high concentrations of
the contaminant. Because the exposure concentration can be solved as a
function of time, the user can observe how concentration increases or
decreases with time or other changes in the model input parameters.
This allows the user to consider administrative controls such as
limiting the time of the operation, the quantity of material emitted by
the process, or determining how long after an operation a worker can
safely enter a previously contaminated area. In some cases, work tasks
and processes that are time-varying can be communicated to the CFD
model through time-varying boundary conditions.
    Models require a defined geometry (i.e., work space), and this step
in the model building may be resource intensive. To construct
geometries of complex work environments, OSHA would need to gather the
necessary information to model the work environment. This includes
taking measurements of the work area, machinery, engineering control
specifications (e.g., exhaust face velocities, spray systems flow
rates), and any other objects or activities that may affect the air flow
in the area of interest. Moreover, gathering site-specific information
for building CFD models can be integrated with traditional industrial
hygiene survey activities. OSHA is interested in identifying ways to
reduce the time and money that may be spent recreating work
environments. One alternative is to import facility layouts in an
electronic format (such as CAD) into the modeling software. If an
establishment has its facility layout in this format, then the model
designer would not have to take physical measurements and recreate the
work area by 3-D modeling.
    Question IV.B.2: In cases where there is no exposure information
available, to what degree should OSHA rely on modeling results to
develop exposure profiles and feasible control strategies? Please
explain why or why not.
    Question IV.B.3: What partnerships should OSHA seek to obtain
information required to most efficiently construct models of work
environments? More specifically, how should OSHA select facility
layouts to model that are representative of typical work environments
in a particular industry? Note that the considerations should include
variables such as work area dimensions, production volumes and
ventilation rates in order to develop models for both large and small
scale operations.
    Models must undergo validation and testing to determine if they
provide an accurate prediction of the physical phenomenon under
consideration, or in this case, the concentrations of air contaminants
to which workers could be potentially exposed. Sensitivity analyses can
be used to determine if model outputs are consistent given minor
changes to grid cell size and time step duration. Grid cell size refers
to the division of space according to nodes, and time step refers to
the value attributed to the time variable to numerically solve the
equations with reference to the nodes. Another method for model
evaluation is the comparison between the solutions of different models
to the same problem in that a similarity of findings across multiple
CFD models would provide greater confidence in the results. Arguably,
the best performance evaluation is the comparison of model results to
those of a field experiment that simulates on different scales the
actual work environment.
    This method of predicting workplace exposures has some potential
advantages over traditional industrial hygiene sampling methods.
Patankar (1980; Ex. #42) explains some of the advantages of theoretical
calculations, in a general sense, to predict heat transfer and fluid
flow processes. Some of these are:
     Low Cost: In many current and future applications, the
cost of a computational method may be lower than the corresponding
sampling cost. As mentioned above, the most resource-consuming aspect
of solid modeling is simulating the geometry that resembles actual
physical space of work environments.
     Speed: A numerical solution to predict exposures can be
obtained very easily in a day. A user could manipulate different
configurations regarding worker positioning and engineering controls to
find an optimal control strategy.
     Complete information: A computer solution provides the
values of all relevant variables throughout the domain of interest.
These variables cover fluid flow patterns, areas in the geometry with
highest concentrations of contamination, exposure values at any point
in the geometry, time profile of contamination, and exposure results
based on different control configurations. Traditional industrial
hygiene sampling does not allow for this level of analysis as it
measures results based on a particular work environment, and it cannot
distinguish how each independent variable (e.g., changes in the
workplace during sampling) affects the exposure result.
     Ability to simulate realistic conditions: A computer
solution can accommodate any environmental condition and the values for
all variables that affect the solution can be easily modified to fit a
particular scenario.
    Patankar (1980; Ex. #42) also discusses the disadvantages of
theoretical predictions to address heat transfer and fluid flow
processes, and they are applicable to exposure modeling. The solutions
obtained depend on the mathematical model used to simulate the
situation, the value of the input parameters, and the numerical method
used to obtain a solution. As Patankar notes, "a perfectly
satisfactory numerical technique can produce worthless results if an
inadequate mathematical model is employed". This is why it is
imperative that the mathematical model chosen actually resembles the
physical phenomena under consideration.
    The Agency also realizes that even if an appropriate mathematical
model and numerical method are obtained to describe contamination in a
workplace, the exposure modeling approach may prove to be more
resource-intensive than traditional industrial hygiene sampling for
work environments with complex geometries. In these situations, OSHA
would have to develop a site visit protocol for gathering dimensions of
the work environment of interest. The information to be collected
includes the dimensions of the physical space, the ventilation system
that affects airflow patterns, and other details (such as location and
size of windows, doors, and large obstructions).
    Despite these limitations, modeling promises to provide significant
advantages that could help OSHA construct more robust technological
feasibility analyses while reducing the considerable amount of
resources the Agency already expends on them. In addition to CFD
modeling, the Agency will continue to investigate other exposure
modeling techniques and their applicability in the rulemaking process.
    Question IV.B.4: Should OSHA use only models that have been
validated? If so, what criteria for model validation should be
employed?
    Question IV.B.5: What exposure models are you aware of that can be
useful for predicting workplace exposures and help OSHA create exposure
profiles and in what circumstances?
    At this time, OSHA is primarily examining the possibility of
incorporating CFD models to indoor work operations. Most general
industry and some construction operations are performed indoors. As the
Agency conducts more research on the applicability of CFD models to
predict workplace exposures, outdoor models will also be considered. As
such, OSHA is interested in obtaining input from parties experienced in
these models.
    Question IV.B.6: Should OSHA consider CFD models primarily for
indoor operations, outdoor operations, or both? What limitations exist
with these two different types of models?
    Various U.S. federal agencies have used CFD modeling for projects
related to indoor air quality and/or occupational health and safety.
Preliminary research indicates that this CFD modeling work has been
performed mostly for academic and research purposes. There is little
information available discussing the use of CFD modeling for the
purposes of litigation and/or regulatory decision-making.
    NIOSH has used CFD on a variety of internal research initiatives
that involve evaluating and controlling airborne exposures. Among other
projects, NIOSH has used CFD modeling to:
     Evaluate potential exposure concentrations to hexavalent
chromium (CrVI), hexamethylene diisocyanate (HDI), methyl isobutyl ketone
(MIBK), and others with different ventilation control configurations
during spray painting operations at a Navy aircraft paint hangar. In this
study, NIOSH also tested and validated the predictive value of CFD modelling
against methods of physical sampling by conducting workplace air sampling
and comparing with model results. The project was performed with assistance
from the Naval Facilities Engineering Command (NAVFAC) and the Navy Medical
Center San Diego (NMCSD) (NIOSH, 2011a; Ex. #43),
     Study the effectiveness of ventilation systems for
controlling Tuberculosis (NIOSH, 2010; Ex. #44),
     Evaluate emission controls for mail processing and
handling facilities (NIOSH, 2010; Ex. #44),
     Better understand the role airflow and ventilation play in
disease transmission in commercial aircraft cabins (NIOSH, 2010; Ex.
#44),
     Simulate different air sampling methods to better
understand how sampling methods can assess exposure (NIOSH, 2010; Ex.
#44), and
     Help better understand the effectiveness of various forms
of exposure control technologies in the manufacturing and
transportation, warehousing, and utilities in the National Occupational
Research Agenda (NORA) Sectors (NIOSH, 2011b; Ex. #45).
    Additionally, NIOSH has also used CFD models in mine safety
research:
     NIOSH conducted a CFD study to model the potential for
spontaneous heating in particular areas of underground coal mines
(Yuan, L. et al., 2006;  Ex. #46). The purpose of the study was to
provide insights into the optimization of ventilation systems for
underground coal mines that face both methane control and spontaneous
combustion issues.
     NIOSH looked at the rate of flame spread along combustible
materials in a ventilated underground mine entry. CFD models were used
to estimate the flame spreading rates of a mine fire (Edwards, J. C.,
and Hwang, C. C., 2006;  Ex. #47).
     NIOSH has also used CFD modeling to model inert gas
injection and oxygen depletion in sealed areas of underground mines
(Trevits, M. A., et al., 2010; ; Ex. #48). CFD simulations were created
to model inert gas injections that aim to eliminate explosive
atmospheres that form in sealed mine areas. The CFD model was able to
quantify oxygen depletion and gas leakage rates of the sealed area.
    EPA has conducted a substantial amount of work using CFD modeling
to assess outdoor air quality. However there is little information
available on EPA projects that have used CFD to evaluate indoor air
quality.
    As part of the Labs21 program, EPA, in conjunction with the
Department of Energy, has published a guidance document for
optimization of laboratory ventilation rates (EPA & DOE, 2008; Ex #49).
The guidance is geared towards architects, engineers, and facilities
managers, in order to provide information about technologies and
practices to use in designing, constructing, and operating safe,
sustainable, high-performance laboratories. EPA advocates the use of
CFD simulations to determine the airflow characteristics of a
laboratory space in order to improve ventilation systems and increase
safety and energy efficiency.
    The Building and Fire Research Laboratory of National Institute of
Standards and Technology (NIST) developed a CFD model to simulate the
transport of smoke and hot gases during a fire in an enclosed space
(NIST, 1997; Ex. #50). The results of the study and an extensive
literature review indicated to NIST that CFD can have significant
benefits in the study of indoor air quality and ventilation. The report
resulting from this study provides a thorough description of CFD and
provides recommendations for future directions in CFD research.
    The Building and Fire Research Laboratory of NIST has also used CFD
to model the effects of outdoor gas generator use on the air
concentrations of carbon monoxide inside nearby buildings (NIST, 2009;
Ex. #51). Using CONTAM (a mathematical indoor air quality model),
coupled with CFD simulations, the researchers were able to determine
factors (e.g., generator positioning, wind direction) that contributed
to elevated carbon monoxide accumulation in the building.
    As OSHA continues to explore the option of incorporating CFD
modeling into its technological feasibility analyses, the Agency will
conduct further research on existing models.
b. The Potential Role of REACH in Technological Feasibility
    Similar to the evaluation of chemical substances by the European
Chemicals Agency (ECHA) and the European Commission before making a
decision to ban or restrict the use of a substance, OSHA must evaluate
information on health effects, exposure levels, and existing controls
before setting a new or revised PEL. However, ECHA requires chemical
manufacturers to generate the information evaluated by government
decision-makers, while in the U.S., OSHA itself is responsible for
generating, researching, and evaluating the relevant information.
    As explained in more detail above, OSHA creates industry profiles
to evaluate the technological feasibility of a standard. The objective
of these profiles is to estimate the number of workers potentially
exposed to occupational hazards. OSHA relies on information from
numerous sources including the U.S. EPA, U.S. DOL, U.S. Census Bureau,
NIOSH, scientific publications, and site visits to identify specific
industries where workers are potentially exposed to hazards.
    Acquiring data from these sources is straightforward and usually
achieved through standard procedures. However, these sources often
contain data gaps or inconclusive information. Thus, new sources of
information are needed to fill existing data gaps and strengthen OSHA's
analyses.
    Since similar types of data are currently being developed and
submitted by manufacturers and importers under REACH, this information
could provide an additional reference source for OSHA to utilize. The
incorporation of REACH data into OSHA's technological feasibility
analyses could greatly assist the Agency in creating a more exhaustive,
thorough, and complete analysis. The information developed during the
REACH registration process could help OSHA better understand the
industries, uses, processes, and products in which a chemical of
concern is used, gain knowledge about the risk management measures and
controls currently in place, and develop scenarios where exposure may
be greatest. Exposure information generated by manufacturers in a
chemical safety assessment could be valuable for completing exposure
profiles on chemicals where current references for field sampling
analytical data are limited. In addition, utilizing information
presented in exposure scenarios that describe the conditions under
which a chemical can be used safely (i.e., risk management measures and
operating conditions) could provide insight on currently employed
industry control methods and their effectiveness.
    While the benefits of incorporating REACH data into OSHA's
technological feasibility analyses seems promising, challenges such as
data access and data validity have been identified as potential
drawbacks. Despite provisions under REACH that require the public
availability of data and the sharing of data with other government
agencies, the European Chemicals Agency, which maintains the REACH
databases, has not yet made some of the information available, including
information generated for and compiled in the chemical safety assessment.
Additionally, some manufacturers and importers may be prohibited from
sharing the data generated for REACH directly with other entities for
non-REACH purposes due to agreements made among the members of groups
organized under REACH to more efficiently share the information needed
for the registration of a chemical.
    Question IV.B.7: How can exposure information in REACH be
incorporated into OSHA's technological feasibility analysis?
c. Technological Feasibility Analysis With a Focus on Industries With
Highest Exposures
    OSHA's technological feasibility analysis is one of the most
resource-intensive parts of the rulemaking process. OSHA typically
analyzes exposures in all industries and job categories within those
industries that show potential for exposures and determine whether a
proposed exposure limit can be achieved in most operations most of the
time. These can range from industries that are constantly experiencing
exposures in most job categories above an existing PEL or the
regulatory alternatives, to industries where only a few job categories
have shown elevated exposures. OSHA has also utilized an application
approach in which it analyzed exposure associated with a specific
process across a number of different industries.
    The Agency is investigating whether it is appropriate to focus
future technological feasibility analyses only on job categories that
have the highest exposures. An analysis performed in this manner may
reduce the amount of time and money OSHA has to expend to prove
feasibility. In many cases the control methods applicable for one
industry may also be effective in reducing exposures in other
industries. By determining the additional engineering controls and work
practices necessary to reduce the most elevated exposures to a level
specified by a regulatory alternative, the Agency could propose that
similar control strategies (wherever applicable) would also be
effective in reducing lesser exposures to that same level. In other
words, by making feasibility findings in the most problematic
industries, OSHA would argue that all other industries would also be
able to comply with a regulatory alternative. A related possibility is
for OSHA to make a feasibility determination based on enforcement
activities of the proposed or lower PEL in other geographic
jurisdictions, e.g., other states.
    Question IV.B.8: To what extent and in what circumstances should
OSHA argue that feasibility for a regulatory alternative can be
established by proving the feasibility of reducing the highest
exposures to the level proposed by that regulatory alternative?
    Question IV.B.9: To what extent and in what circumstances can OSHA
argue that feasibility for a regulatory alternative can be established
by the enforcement of a lower PEL [e.g., the 1989 PEL (See Appendix B)]
by an individual state or states?
    Question IV.B.10: What are the appropriate criteria that OSHA
should use to assess whether control strategies implemented in a
process from one industry are applicable to a process from another
industry (e.g., similarity of chemicals, type, extent and duration of
exposures, similar uses)?
    Question IV.B.11: Regardless of the industries involved, are there
criteria that OSHA should use to show that control strategies
implemented in a process from one operation are applicable to a process
from another operation? Please explain.
    The Agency realizes that analyses performed in this manner may have
some implications for smaller firms that may find it harder to
implement resource intensive control strategies than larger firms.
Additionally, the control strategies from the most problematic
industries may not be similar to those that may be needed for
industries with lower exposures because the processes and sources of
exposure require different control methods.
    Question IV.B.12: How should OSHA take into consideration the size
of a business of facility when determining technological feasibility?

C. Economic Feasibility in Health Standards

    The purpose of this section is (1) to discuss how and why OSHA
currently conducts its economic feasibility analysis of health
standards, and (2) to examine approaches to economic feasibility that
might involve less time and fewer resources.
1. OSHA's Current Approach to Economic Feasibility
    The Agency's existing approach to economic feasibility rests
directly on relevant language in the OSH Act, as interpreted by the
courts, requiring OSHA to establish that new standards are economically
feasible. OSHA also conducts economic analysis of its regulations in
compliance with other legislation and as a result of executive orders
that require analysis of the benefits and costs of a regulation as a
whole, and in the case of the Regulatory Flexibility Act, some estimate
of the economic impacts on small entities. However, the degree of
industry detail provided in OSHA's economic analyses is primarily a
function of judicial interpretation of the economic feasibility
requirements of the OSH Act. The development of the law on economic
feasibility is discussed in detail in Section III. Below we discuss
potential alternatives to current methods of economic feasibility
analysis, and then follow with a brief discussion on how the other
analytical requirements OSHA is required to meet might be satisfied.
    As guided by the courts, OSHA develops economic feasibility
analyses that cover every affected industry and process. OSHA has not
always taken this position. For example, in its economic and
technological feasibility analysis of benzene, OSHA examined only
industries believed to be the worst in terms of significant exposure to
benzene. Since then, however, OSHA has attempted to cover all affected
industries in its feasibility analysis.
    The courts have suggested that the economic feasibility analysis
must be reasonably detailed. In the Air Contaminants case, the court
said:

    Indeed, it would seem particularly important not to aggregate
disparate industries when making a showing of economic feasibility .
. . [R]eliance on such tools as average estimates of cost can be
extremely misleading in assessing the impact of particular standards
on individual industries. AFL-CIO v. OSHA, 965 F.2d 962, 982 (11th
Cir. 1992) ("Air Contaminants"). (Ex. #8)

However, the court added:

    We are not foreclosing the possibility that OSHA could properly
find and explain that certain impacts and standards do apply to
entire sectors of an industry. Two-digit SICs could be appropriate,
but only if coupled with a showing that there are no
disproportionately affected industries within the group. Air
Contaminants, 965 F.2d at 982 n.28

    In the hexavalent chromium case, Public Citizen Health Research
Group v. United States Dep't of Labor, 557 F.3d 165, 178 (3d Cir. 2009;
Ex. #14), the court recognized that OSHA had the flexibility to
demonstrate technological feasibility on a process or activity rather
than industry-by-industry basis, if the processes or activities are
sufficiently similar from industry to industry. The court, however, did
not address the question of whether the same flexibility applies to
economic feasibility. OSHA, especially in health standards, has tried
to provide the most detailed analysis of industries and processes that
resources permit. For most recent health standards, this has meant the
use of the lowest level industry codes for which industry data are
available, and where more than one process is used in an industry,
consideration of each process separately. Further, in order to assure
that a regulation does not alter the competitive structure of an
industry, OSHA normally analyses three size classes of employer within
each industry: All establishments, small firms as defined by SBA, and
small firms with fewer than twenty employees (always smaller than the
SBA definitions). For the typical OSHA substance-specific health
standard, OSHA analyses each of the controls for each of the many
processes in which the substance might appear, and then of each
industry in which any process might appear, and then of three sizes of
establishment within the industry. Finally, OSHA examines the varying
levels of exposure and controls within an industry and develops
analyses that reflect these differences within an industry. In terms of
the form of the analysis, OSHA has followed the advice of the D.C.
Circuit to "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 v. Marshall, 647 F.2d 1189, 1272 (D.C. Cir. 1980; Ex. #12)
("Lead I").
    In response to this guidance, OSHA develops detailed estimates of
the costs of a health standard for each affected industry, and by the
three size categories of establishment. The result is that the economic
analyses of health standards routinely contain a series of tables
showing costs for each industry by multiple size classes of firms
within the industry, and sometimes for more than one process per
industry. Each entry in these tables is documented by detailed
explanations of how the costs were estimated for each industry and size
class and level of exposure.
    OSHA then makes a determination for each industry whether or not
these costs are likely to threaten the existence or competitive
structure of that industry. In order to do this, OSHA first constructs
a "screening analysis" for each industry. For the purposes of this
screening analysis, OSHA combines its estimates on the costs per
establishment of various sizes with statistical data on the profits and
revenues of the affected establishment sizes, and then calculates costs
as a percentage of profits and revenues. For most industries, the costs
in comparison to revenues and profits are so small that, in OSHA's
view, no reasonable person could think that the costs could possibly be
expected to threaten the existence or competitive structure of an
industry. Where the costs are not this small, OSHA conducts a variety
of further economic analysis, depending on the economic situation,
nature of the costs, the affected industry, and the economic data
available.
    This basic approach to economic feasibility analysis has been used
for many health standards, and the approach has generally been
successful in assuring that OSHA standards are economically feasible.
In the PELs rulemaking, where OSHA tried a more general approach, the
court found the level of detail inadequate. Similarly, OSHA has
encountered problems when the Agency did not have an adequate level of
detail with respect to the exposure profile and the technological
feasibility analysis, such as for dry-color formulators of cadmium
pigments. OSHA's eight lookback studies, conducted under both Sections
610 of the Regulatory Flexibility Act and Section 5 of Executive Order
12866, have not found any instance in which subsequent study showed
that a standard had threatened the existence of or brought about
massive dislocation within an industry.
    OSHA can reasonably say that it has found a methodology such that
the Agency's determinations of economic feasibility have both been
considered adequate by the courts and proven to be accurate in
determining regulations to be feasible when re-evaluated by
retrospective analysis. However, the resulting methodology is extremely
resource intensive and time-consuming because OSHA always has to make
detailed cost estimates and provide detailed statistical data for every
single process and industry affected. For this reason, OSHA wants to
consider whether there may be methods that can short-cut this process
and still meet all of OSHA's legal requirements.
    The remainder of this section examines two kinds of alternative
approaches to accelerating the process and reducing the resources
needed to produce health standards. One kind of alternative involves
formulating health standards differently. The second kind involves
different kinds of analysis OSHA might perform.
2. Alternative Approaches to Formulating Health Standards That Might
Accelerate the Economic Feasibility Analysis
    One approach to simplifying, speeding up, and making the
development of standards less resource intensive would be to have the
standards themselves address health issues in a way that involves less
analysis for any given standard. Health standards can be analyzed
faster to the extent that there are fewer processes and/or fewer
industries to analyze. It would be less time consuming for OSHA to
analyze a health standard for a single process rather than a single
substance that is found in dozens of processes. OSHA already has a
variety of process-oriented standards that partially address health
hazards in such areas as abrasive blasting, welding, and
electroplating. Control banding also represents an approach that,
following the hazard assessment, examines controls for specific
processes. In control banding, the hazards are generic, but the
controls are process specific. Process-oriented approaches would be
most useful for processes widely used in a variety of settings--
abrasive blasting, degreasing, welding, etc. Industry-by-industry
economic feasibility analysis for a process-oriented approach would be
enormously simplified by the fact the controls and their costs would be
very similar across industries. As a result, OSHA could develop more
detailed and more secure cost estimates, with full opportunities for a
variety of affected parties to comment on those estimates. This
approach might also serve to greatly simplify the technological
feasibility analysis. On the other hand, since process-oriented
standards commonly involve multiple substances, risk assessment issues
might be more complex.
    A related approach to speeding up at least portions of substance
specific health standards might be to regulate a single substance
process by process in multiple rulemakings--for example, regulate
exposures to hexavalent chromium in electroplating, then in welding,
and then painting. By producing process standards in this manner,
rather than waiting until analyses of all processes and industries is
completed, OSHA could potentially address the most severe exposures
much more rapidly. This approach could also allow OSHA to ignore
processes where the exposures are likely to be small and the chance of
exceeding a PEL minimal. Though this approach might result in portions
of a substance-specific standard being produced more quickly, the
approach would probably require more resources for multiple hearings
and docket analyses. A major disadvantage of this approach is that it
would result in the possibility that workers in industries not yet
regulated would have to endure exposures higher than those in regulated
industries. Another disadvantage might be that the risk assessment
would be subject to multiple public hearings as each industry or
process was regulated.
3. Alternative Analytic Approaches to Economic Feasibility of Health
Standards
    A different approach to producing less resource-intensive and time-
consuming economic feasibility analyses would be to re-examine whether
OSHA's basic approach of estimating the costs of each process,
industry, size class, and possible level of control is really necessary
in all cases given how the courts have defined economic feasibility.
The key to meeting the legal requirements is to return to the concept
of economic feasibility. In the Lead I decision, the court stated:

    A standard is feasible if it does not threaten "massive
dislocation" to . . . or imperil the existence of the industry. No
matter how initially frightening the projected . . . costs of
compliance appear, a court must examine those costs in relation to
the financial health and profitability of the industry and the
likely effect of such costs on unit consumer prices. More
specifically . . . the practical question is whether the standard
threatens the competitive stability of an industry. Lead I, 647 F.2d
at 1265 (citations omitted). (Ex. #12)

    As the court recognized, this is a strong criterion. In the real
world, industries are rarely eliminated or have their competitive
structure radically altered for reasons related to changes in their
costs, and it is changes in costs that courts recognized as the
principle reason a regulation might not be economically feasible.
Radical changes in industries tend to come from two major causes. Most
are the result of changes in demand such that the public is no longer
interested in the product or service an industry provides, for such
reasons as technological obsolescence or the existence of better
substitutes. Some radical changes in industries are the result of
foreign competition. However, foreign competition applies largely, in
an OSHA context, to manufacturing, but not to construction, utilities,
domestic transportation, or most services that OSHA regulates.
    OSHA is not aware of any instance in which an OSHA regulation
eliminated or altered the competitive structure of an industry--though
in some cases, a combination of liability-based concerns, environmental
regulations, and OSHA regulation may have radically altered the use of
a product. For example, asbestos is not used in many applications where
it was once commonplace. Benzidine-based dyes have disappeared from the
U.S. marketplace. However, these cases had no effect on the viability
of user industries or their employment. Insulation contractors still
install insulation--it just no longer contains asbestos. Dyers continue
to dye textiles and leather all the colors benzidene-based dyes
imparted, but without using benzidene-based dyes. The chief effect has
been substitution away from a substance. This has resulted in serious
economic impacts on a limited number of producers of the substance but
little economic impact on the thousands of users of the substance who
simply found a substitute. It would seem that such substitution away
from a substance is not the kind of economic change that would make a
regulation economically infeasible.
    OSHA might be able to place major emphasis on evidence that a
significant portion of an industry is already meeting a standard. Such
evidence is an obvious indication that a standard is both
technologically and economically feasible for that industry. After all,
the actual fact that a majority of employers of all sizes in an
industry is meeting a standard, while remaining viable, should be more
convincing than a set of cost estimates in an economic analysis
predicting that employers in a given industry could meet the standard.
Actual empirical evidence of a proposition is normally considered
superior to theoretical evidence for a proposition. There are several
reasons why many or most employers in an industry may already meet a
standard--these include ease of meeting the standard, industry
consensus standards, and concern about liability.
    Similarly, the fact that a state or other jurisdiction has already
implemented a requirement and that firms within the state are generally
following the requirement would represent very strong evidence that a
requirement is economically and technologically feasible. For example,
twenty-two states currently operate their own OSHA programs that cover
both private sector and State and local government employees, and five
states cover public employees only. Of the twenty-two states that cover
both private and public sector employees, five states (South Carolina,
Minnesota, Tennessee, Vermont and Washington) are still enforcing the
1989 PELs, and did not revert to the less protective PELs when the
Court remanded the Air Contaminants rule. (Ex. #8) Michigan is also
enforcing the 1989 PELs in general industry, but not in construction.
Three states (Connecticut, Illinois, and New York) are enforcing the
1989 PELs in the public sector only. California enforces its own PELs
which in many cases are substantially lower than OSHA's. Situations in
which most firms in a state meet a potential requirement of a standard
are particularly convincing because they show that employers are not
only able to carry out the requirement, but can do so even in
competition with employers who are not required to meet such a
requirement.
    Nevertheless, OSHA is aware that some care must be taken with
evidence that all or most firms in an industry or in an industry within
a state meet a requirement. It is particularly important to determine
whether those who do not meet the requirement might require
fundamentally different controls, have different costs, or operate in a
different market in spite of being in the same statistical industry.
Consider a standard addressing a specific metal. Most firms in an
industry may find the standard easy to meet because they only use the
metal in alloys that call for a very small percentage of the metal.
However, those firms that use alloys with high percentages of the metal
might be unable to meet the standard. This would not be apparent
looking solely at aggregate industry data. OSHA should take reasonable
steps to determine that those that did not meet the standard do not
have important technological or economic characteristics that are
different from those that did.
    Under this approach, OSHA could conclude that a standard is
feasible where a state already had such a standard if it first
determines that (1) the standard is enforced; (2) employers in the
state in fact meet the standard; and (3) which of the relevant
industries and technologies are represented within that state.
    However, in spite of these caveats, it would frequently take OSHA
less time and fewer resources to demonstrate that a standard is
technologically and economically feasible by showing that employers in
the industry already meet the standard than by the full identification
of control technologies, exposure levels achieved by those
technologies, the costs of the technologies, and the economic impacts
of these technologies that OSHA now undertakes.
    As noted above, at one point in the Lead I decision, the court
suggested OSHA develop a "reasonable estimate of costs." However at
another point in this decision the same court clarified:

    [T]he court probably cannot expect hard and precise estimates of
costs. Nevertheless, the agency must of course provide a reasonable
assessment of the likely range of costs of its standard, and the likely
effects of those costs on the industry . . . And OSHA can revise any
gloomy forecast that estimated costs will imperil an industry by allowing
for the industry's demonstrated ability to pass through costs to
consumers. Lead I, 647 F.2d at 1266. (Ex. #12)

    OSHA has made little use of the concept of a likely range of costs
or of developing generic approaches to determining a reasonable
likelihood that these costs will not threaten the existence or
competitive structure of an industry.
    OSHA could significantly reduce its resource and time expenditures
by providing ranges of costs, given that the upper end of the range
provides "a reasonable likelihood that these costs will not threaten
the existence or competitive structure of an industry." Such an
approach would not only reduce OSHA's time and effort but also that of
the interested public. Too often stakeholders devote significant time
and effort questioning cost estimates when even the stakeholders'
alternative cost estimate would have no effect on whether the costs
would threaten the existence or competitive structure of an industry.
The simple fact is that both OSHA and its stakeholders spend far too
much time examining the accuracy of cost estimates even when the
highest cost estimates considered would have little effect on the
determination of economic feasibility.
    OSHA could also make more effort to clarify historically the
circumstances under which regulations of any kind have eliminated or
altered the competitive structure of an industry. As noted above, OSHA
has yet to find an instance in which OSHA regulations eliminated or
altered the competitive structure of an industry. A more thorough
exploration of past experiences with OSHA regulations might simplify
OSHA analyses and make it more empirically based in a variety of
situations.
    OSHA believes that it may be able to meet the requirements of
Executive Orders 12866 and 13563 and the Regulatory Flexibility Act
without the kind of industry-by-industry detail that OSHA now provides
in its economic analyses. The requirements of executive orders for
analysis of costs and benefits do not include requirements that they be
made available on an industry-by-industry basis, and OIRA encourages
the reporting of ranges as opposed to precise but possibly inaccurate
point estimates. OSHA believes that the requirements of the executive
orders and for determining if a regulatory flexibility analysis or
Small Business Regulatory Enforcement Fairness Act (SBREFA) Panel is
needed can, in most cases, be met by focusing on those sectors and size
classes where the most severe impacts are expected.
    Question IV.C.1: Should OSHA consider greater use of process
oriented regulations, such as regulations on abrasive blasting,
welding, or degreasing, as an approach to health standards? Should such
an approach be combined with a control banding approach?
    Question IV.C.2: Should OSHA consider issuing substance-specific
standards in segments as the analysis of a particular process or
industry is completed rather than waiting until every process and
industry using a substance has been thoroughly analyzed?
    Question IV.C.3: To what extend and in what circumstances can OSHA
argue that feasibility for a regulatory alternative can be established
by the enforcement of a lower PEL (e. g., the 1989 PEL) by an
individual state or states?
4. Approaches to Economic Feasibility Analysis for a Comprehensive PELs
Update
    Following the Eleventh Circuit's direction in the Air Contaminants
case (956 F.2d at 980-82; Ex. #8) and in Color Pigments Mfrs. Ass'n v.
OSHA, 16 F.3d 1157, 1161-64 (11th Cir. 1994; Ex. #13), OSHA has
typically performed its economic feasibility analyses on an industry-
by-industry basis using the lowest level industry codes for which
industry data are available. While such an approach best insures that
the effect of the standard on small industry segments will be
considered, it is very resource intensive. If OSHA were required to use
of this approach to address feasibility for a comprehensive PELs
update, which would require addressing the feasibility of new PELs for
hundreds of chemicals in hundreds of industry segments, it might
require more resources than the agency would have available.
    There are good reasons to think that the OSH Act does not require
such a detailed level of economic analysis to support a feasibility
finding. The purpose of the OSH Act is to assure all workers "safe and
healthful working conditions," and therefore it is unlikely that
Congress intended for OSHA to meet such demanding analytical
requirements if it meant that the agency could not issue a standard
addressing well-recognized hazards. See, e.g., Public Citizen Health
Research Group v. Dep't of Labor, 557 F.3d 165, 178-79 (3d Cir. 2009;
Ex. #14) ("Hexchrome") (rejecting interpretation that OSH Act
required OSHA to research all workplace operations involving hexavalent
chromium exposure to prove feasibility, which would "severely hinder
OSHA's ability to regulate exposure to common toxins"); American
Dental Ass'n v. Martin, 984 F.2d 823, 827 (7th Cir. 1993; Ex. #53)
(OSHA not required to regulate "workplace by workplace"); Assoc.
Bldrs & Contrs. Inc. v. Brock, 862 F.2d 63, 68 (3d Cir. 1988; Ex. #54)
("A requirement that the Secretary assess risk to workers and need for
disclosure with respect to each substance in each industry would
effectively cripple OSHA's performance of the duty imposed on it by 29
U.S.C. 655(b)(5); a duty to protect all employees, to the maximum
extent feasible.").
    Indeed, the requirement that an OSHA standard not threaten
"massive dislocation" or "imperil the existence" of an industry is
an outgrowth of the idea that OSHA may adopt standards that may cause
marginal firms to go out of business if they are only able to make a
profit by endangering their employees. See Industrial Union Dep't, AFL-
CIO v. Hodgson, 499 F.2d 467, 478 (XX Cir. 1974; Ex. #55). And the
notion that the determination must be made on an industry basis arises
from cases in which OSHA attempted to do just that; the statute does
not require feasibility to be evaluated in this way. See Lead I, 647
F.2d at 1301 (where OSHA attempted to determine the feasibility of the
lead standard on an industry-by-industry basis, noting that the parties
did not dispute that feasibility was to be determined in that manner);
Hexchrome, 557 F.3d at 178 ("nothing in 29 U.S.C. 655(b)(5) requires
OSHA to analyze employee groups by industry, nor does the term
'industry' even appear"). The approach articulated by the Air
Contaminants court, which places an affirmative duty on OSHA to
establish that proposed standards would not threaten even the smallest
industry segments before adopting a standard, creates a heavy
analytical burden that is not necessarily required by the statute.
    As the Lead I court notes, in the case of a standard requiring an
employer to adopt only those engineering and administrative controls
that are feasible, what really is at stake in OSHA's feasibility
determinations is whether OSHA has justified creating a presumption
that the implementation of such controls are feasible. 647 F.2d at
1269-70. Thus, OSHA need not "prove the standard certainly feasible
for all firms at all times in all jobs." 647 F.2d at 1270. The court
recognized that under this approach, some employers might not be able to
comply with a standard, but noted that the statute offers those employers
several alternatives: requesting a variance, asserting a feasibility
defense in an enforcement proceeding, or petitioning the agency to revise
the standard. 647 F.2d at 1270.
    As noted above, most of OSHA's current PELs are over 40 years old,
and are based on science that is even older. It seems unlikely that a
statute enacted to protect workers against chemical health hazards
would preclude OSHA from updating hundreds of those PELs unless it can
show that each is feasible in each of the smallest industry segments in
which the chemical is used. The question, then, is what level of
analysis would be sufficient to justify a presumption that the standard
is feasible, shifting the burden to the employer as allowed by Lead I.
    If OSHA moved forward with a global PELs update, the Agency might
consider analyzing economic feasibility at a higher level than it has
typically employed in substance specific health standards. In order to
do so, OSHA would need to develop criteria as to what chemicals are
suited to be part of a PELs rulemaking rather than subject to a
substance-specific rulemaking. For example, if the rulemaking record
showed that, for a specific chemical application group, generally
available exposure controls had not been successful in achieving the
proposed PEL, then this chemical or at least the application group
would be transferred from updated PELs rulemaking to being a candidate
for further study and possible inclusion in a substance-specific
rulemaking. The goal under this approach would be to develop a
reasonable basis for believing that the chemicals and application
groups remaining in a PELs-update rulemaking are (1) likely to be
economically feasible; and (2) subject to relatively simple and easily-
costed controls that are likely to be relatively homogenous across
industries.
    As a result, rather than accumulating data at the lowest industry
level available regarding exposures and controls needed for each
chemical for which a new PEL would be adopted, OSHA could consider a
more general approach. For example, OSHA might conduct an economic
feasibility analysis at the industry level for which sufficient
exposure data are currently available. It might use a control banding
approach in order to determine the types of controls necessary to
comply with a new PEL, and validate models to implement each type of
control based on variables such as establishment size and process type.
The results of this analysis would be used to build up costs at the
industry level. It is possible that the results of such an analysis
might be better characterized in ranges, and of sufficient precision to
establish feasibility at a level as low as the method that OSHA
typically uses. Under this approach, a determination made in this way
would be presumptively sufficient to establish feasibility in the
absence of contrary evidence provided by commenters. If such evidence
were presented, OSHA would address it and incorporate it into its
feasibility analysis supporting the final rule.
    Question IV.C.4: Should OSHA consider providing ranges of costs for
industries in situations where even the upper range of the costs would
obviously not provide a threat to the existence of competitive
structure of an industry?
    Question IV.C.5: What peer-reviewed economics literature should
OSHA consult when determining whether the competitive structure of an
industry would be altered? Are there any instances where an OSHA
standard did threaten the existence or competitive structure of an
industry? What were they and what is the evidence that an OSHA standard
was the origin of the difficulties?
    Question IV.C.6: Should OSHA consider and encourage substitution
and elimination of substances that cause significant risk in workplaces
even if such substitution or elimination will eliminate or alter the
competitive structure of the industry or industries that produce the
hazardous substance?
    Question IV.C.7: Are there other approaches OSHA could use that
would provide for more timely and less resource-intensive economic
feasibility analyses?
    Question IV.C.8: In determining the level of industry detail at
which OSHA should conduct an economic feasibility analysis for a
comprehensive PELs update, what considerations should OSHA take into
account? What level of detail do you think is sufficient to justify the
presumption of feasibility for such a standard? Please explain.
    Question IV.C.9: Are the methodologies suggested above appropriate
to establish economic feasibility for a comprehensive PELs update? Why
or why not? What other cost effective methods are available for OSHA to
establish economic feasibility for such a rulemaking?
    Question IV.C.10: What factors should OSHA consider in determining
whether a chemical should be part of an overall PELs update or subject
to substance-specific rulemaking? Should OSHA consider some application
groups for a given chemical as subject to a PELs update rulemaking if
some other application groups present feasibility issues that make them
inadvisable candidates for a PELs rulemaking?

V. Recent Developments and Potential Alternative Approaches

    Wide access to information on the Internet and the development of a
global economy has shifted occupational safety and health from a
domestic to a global concern. Countries often struggle with similar
experiences and challenges related to exposure to hazardous chemicals,
and sharing information and experiences across borders is a common
practice. Global data sharing allows for the widespread and rapid
dissemination of available chemical information to employers,
employees, managers, chemical suppliers and importers, risk managers,
or anyone with access to the Internet. The development of hazard
assessment tools that take advantage of readily available hazard
information make it possible for employers to implement effective
exposure control strategies without the need to rely solely on OELs.
    Some of these resources for data and tools that OSHA may use more
systematically in the future for hazardous chemical identification and/
or assessment are addressed in Section V.

A. Sources of Information About Hazardous Chemicals

    In order to design and implement appropriate protective measures to
control chemical exposures in the workplace, employers need reliable
information about the identities and hazards associated with those
chemicals. OSHA is considering ways in which recently developed data
sources could be used by the Agency and employers to more effectively
manage chemical hazards in the workplace. Developments in the use of
structure--activity data for grouping chemicals having similar
properties, the Environmental Protection Agency's High Production
Volume (HPV) Chemicals, OSHA's Hazard Communication standard and the
Globally Harmonized Hazard Communication Standard, health hazard
banding, the European Union's Registration, Evaluation, Authorization,
and Restriction of Chemicals (REACH), are discussed here. OSHA is
interested in stakeholders' comments on how the Agency may make use of
any of these data sources or other alternative data or information
sources not discussed here to better manage workplace chemical exposures.
1. EPA's High Production Volume Chemicals
    One potential source of relevant and timely information on
chemicals that OSHA may make better use of in the future is the data on
High Production Volume chemicals that are being collected by the EPA
and the Organization for Economic Cooperation and Development (OECD).
The OECD program lists approximately 5,000 chemicals on its list, and
OSHA has determined that 290, or 62 percent of the 470 substances with
PELs are included on the OECD list.
    Under the HPV program, EPA has identified over 2,000 chemicals that
are produced in quantities of one million pounds a year or more in the
United States. It would appear that these chemicals are thus
economically significant in the US, and there are likely to be a large
number of workers exposed to them. Through the HPV Challenge program,
EPA encouraged industry to make health and environmental effects data
on these HPV chemicals publicly available. To date, data on the
properties of approximately 900 HPV chemicals has been made available
through the Agency's High Production Volume Information System (HPVIS)
(U.S. EPA, 2012a; Ex. #56). For each HPV chemical, the database
includes information on up to 50 endpoints on physical/chemical
properties, environmental fate and pathways, ecotoxicity, and mammalian
health effects. EPA has also used this information to generate publicly
available chemical hazard characterizations, which provide a concise
assessment of the raw technical data on HPV chemicals and evaluate the
quality and completeness of the data received from industry (U.S. EPA,
2013d; Ex. #63).
    Data on HPV chemicals submitted through the OECD's program are
available through its Global Portal to Information on Chemical
Substances, eChemPortal (OECD, 2013; Ex. #58). In addition to searching
data collected through the EPA HPV and OECD HPV programs, eChemPortal
allows for simultaneous searching of 26 databases for existing publicly
available data on the properties of chemicals, including: physical/
chemical properties, environmental fate and behavior, ecotoxicity, and
toxicity.
    Question V.A.1. How might publicly available information on the
properties and toxicity of HPV chemicals be utilized by employers to
identify chemical hazards and protect workers from these hazards? OSHA
is also interested to hear from commenters who may currently make use
of these data in their worker protection programs.
2. EPA's CompTox and ToxCast
    EPA has also launched an effort to prioritize the tens of thousands
chemicals that are currently in use for testing and exposure control.
Through its computational toxicology (CompTox) research, the U.S.
Environmental Protection Agency (EPA) is working to figure out how to
change the current approach used to evaluate the safety of chemicals.
CompTox research integrates advances in biology, biotechnology,
chemistry, and computer science to identify important biological
processes that may be disrupted by the chemicals and trace those
biological disruptions to a related dose and human exposure. The
combined information helps prioritize chemicals based on potential
human health risks. Using CompTox, thousands of chemicals can be
evaluated for potential risk at a small cost in a very short amount of
time. A major part of EPA's CompTox research is the Toxicity Forecaster
(ToxCastTM). ToxCast is a multiyear effort launched in 2007
that uses automated chemical screening technologies, called
"highthroughput screening assays," to expose living cells or isolated
proteins to chemicals. The cells or proteins then are screened for
changes in biological activity that may suggest potential toxic
effects.
    These innovative methods have the potential to limit the number of
required animal-based laboratory toxicity tests while, quickly and
efficiently screening large numbers of chemicals. The first phase of
ToxCast, called "proof of concept", was completed in 2009, and it
evaluated more than 300 well studied chemicals (primarily pesticides)
in more than 500 high-throughput screening assays. Because most of
these chemicals already have undergone extensive animal-based toxicity
testing, this enables EPA researchers to compare the results of the
high-throughput assays with those of the traditional animal tests.
(EPA, 2014a; Ex. #59)
    Completed in 2013, the second phase of ToxCast evaluated over 2,000
chemicals from a broad range of sources, including industrial and
consumer products, food additives, and potentially "green" chemicals
that could be safer alternatives to existing chemicals. These chemicals
were evaluated in more than 700 high-throughput assays covering a range
of high-level cell responses and approximately 300 signaling pathways.
ToxCast research is ongoing to determine which assays, under what
conditions, may lead to toxicological responses. The results of this
research then can be used to suggest the context in which decision
makers can use the data. The EPA's Endocrine Disruptor Screening
Program already has begun the scientific review process necessary to
begin using ToxCast data to prioritize the thousands of chemicals that
need to be tested for potential endocrine-related activity. Other
potential uses include prioritizing chemicals that need testing under
the Toxic Substances Control Act and informing the Safe Drinking Water
Act's contaminant candidate lists. (EPA, 2014b; Ex. #60) EPA
contributes the results of ToxCast to a Federal agency collaboration
called Toxicity Testing in the 21st Century (Tox21). Tox21 pools those
results with chemical research, data and screening tools from the
National Toxicology Program at the National Institute of Environmental
Health Science, the National Institutes of Health's National Center for
Advancing Translational Sciences and the Food and Drug Administration.
(EPA, 2014b; Ex. #60)
    Thus far, Tox21 has compiled highthroughput screening data on
nearly 10,000 chemicals. All ToxCast chemical data are publicly
available for anyone to access and use through user-friendly Web
applications called interactive Chemical Safety for Sustainability
(iCSS) Dashboards at http://actor.epa.gov/dashboard/.
    OSHA could use this publicly available information on chemical
properties and toxicity as a part of the Agency's risk assessments that
support the revision and development of permissible exposure limits.
Tox21 could also be used by the Agency for screening chemicals and
prioritizing for risk management.
    Question V.A.2. How might the information on the properties and
toxicity of chemicals generated by CompTox, ToxCast, and/or Tox21 be
utilized by employers to identify chemical hazards and protect workers
from these hazards? OSHA is also interested to hear from commenters who
may currently make use of these data in their worker protection
programs.
3. Production and Use Data Under EPA's Chemical Data Reporting Rule
    Under the EPA's Chemical Data Reporting (CDR) Rule, issued in 2011,
EPA collects screening-level, exposure-related information on certain
chemicals included on the Toxic Substances Control Act (TSCA) Chemical
Substance Inventory and makes that information publicly available to
the extent possible. The CDR rule amended the TSCA Inventory Update
Reporting (IUR) rule and significantly increased the type and amount of
information covered entities are required to report. The 2012 submissions
included data on more chemicals and with more in-depth information on
manufacturing (including import), industrial processing and use, and
consumer and commercial use than data collected under the IUR in 2006
(U.S. EPA, 2013a; Ex. #1).
    The expanded reporting on chemical production and use information
under the CDR could help OSHA better understand how workers are exposed
to chemicals and the industries and occupations where exposures to
chemicals might occur.
4.Structure-Activity Data for Chemical Grouping
    Although toxicity testing for chemicals has increased greatly since
the passage of the Toxic Substances Control Act (15 U.S.C. 2601-2629;
Ex. #62) in the United States, and with similar legislation elsewhere,
toxicity data is only publicly available for a fraction of industrial
chemicals. Since the enactment of TSCA and creation of the TSCA
Interagency Testing Committee (U.S. EPA, 2013c; Ex. #57), the ITC has
recommended testing for hundreds of chemicals, and chemical producers
have conducted more than 900 tests for these chemicals. However,
potentially thousands of industrial chemicals have not been tested.
    With the rapidly expanding development of new chemical substances
and mixtures, the need for toxicity information to inform chemical
safety management and public health decisions in a timely manner has
exceeded the capacity of the government programs to provide those data.
As a result, programs such as the Organization for Economic Cooperation
and Development's (OECD) Screening Information Data Set (SIDS) and the
U.S. EPA High Production Volume (HPV) Challenge programs were designed
to encourage the voluntary development of data. However, even with the
creation of these non-statutory programs, potentially thousands of non-
HPV industrial chemicals go untested. Therefore, chemical
prioritization for screening and testing requires the development and
validation of standard methods to predict the human and environmental
effects and potential fate of chemicals. Where screening and testing
data are sparse, the use of predictive models called structural
activity relations (SARs) or quantitative structural activity
relationships (QSARs) can extend the use of limited toxicity and safety
data for some untested chemicals (Russom et al., 2003; Ex. #64). QSARs
are mathematical models that are used to predict measures of toxicity
from physical characteristics of the structure of chemicals, known as
molecular descriptors.
    Other U.S. and international agencies have explored the use of
chemical groupings to regulate chemicals in order to fulfill their
regulatory and statutory authorities. Under the TSCA Work Plan, the EPA
announced in 2013 that it would begin to assess 20 flame retardant
chemicals and three non-flame retardant chemicals. EPA utilized a
structure-based approach, grouping eight other flame retardants with
similar characteristics together with the chemicals targeted for full
assessment in three groupings. EPA will use the information from these
assessments to better understand the other chemicals in the group,
which currently lack sufficient data for a full risk assessment.
    EPA uses chemical groupings to fill data gaps in its New Chemical
Program. EPA's New Chemical Program, also under TSCA, requires anyone
who plans to manufacture or import a new chemical substance into
commerce to provide EPA with notice before initiating the activity.
This is called a pre-manufacture notification (PMN). EPA received
approximately 1,500 new chemical notices each year and has reviewed
more than 45,000 from 1979 through 2005 (GAO, 2007; Ex. #65). Because
TSCA does not require testing before submission of a PMN, SARs and
QSARs are often used to predict the environmental fate and ecologic
effects. In addition, the EPA makes predictions concerning chemical
identity, physical/chemical properties, environmental transport and
partitioning, environmental fate, environmental toxicity, engineering
releases to the environment, and environmental concentrations. The
agency uses a variety of methods to make these predictions that include
SARs, nearest-analogue analysis, chemical class analogy, mechanisms of
toxicity, and chemical industry survey data and the collective
professional judgment of expert scientific staff, in the absence of
empirical data. The agency uses these methods to fill data gaps in an
assessment and to validate submitted data in notifications. Predictions
are also made by the U.S. EPA Office of Pollution Prevention and Toxics
(OPPT) under TSCA (Zeeman., 1995; Ex. #66). The OPPT has routinely used
QSARs to predict ecologic hazards, fate, and risks of new industrial
chemicals, as well as to identify new chemical testing needs, for more
than two decades. OPPT SAR/QSARs for physical/chemical properties used
for new chemical assessments are publically available (U.S. EPA, 2012b;
Ex. #67).
    In Europe, internationally agreed-upon principles for the
validation of (Q)SARs were adopted by OECD Member Countries and the
Commission in 2004. In 2007, the Inter-organization Programme for the
Sound Management of Chemicals, a cooperative agreement among United
Nations Environmental Program (UNEP); International Labor Organization
(ILO); Food and Agriculture Organization of the United Nations (FAO);
World Health Organization (WHO); United Nations Industrial Development
Organization (UNIDO), United Nations Institute for Training and
Research (UNITAR) and Organization for Economic Co-operation and
Development (OECD) published "Guidance on Grouping of Chemicals" as
part of an ongoing monograph series on testing chemicals. REACH
registrants may rely on (Q)SAR data instead of experimental data,
provided the registrants can provide adequate and reliable
documentation of the applied method and document the validity of the
model. Validation focuses on the relevance and reliability of a model
(ECHA, 2008; Ex. #68).
    The EU Scientific Committee on Toxicity, Ecotoxicity and the
Environment (CSTEE) recommended, in their general data requirements for
regulatory submission, that QSAR data may be used as well as animal
data. A chemical category approach based on the metal ion has been
extensively used for the classification and labeling of metal compounds
in the EU. Other category entries are based on certain anions of
concern such as oxalates and thiocyanates. For these EU classifications
the category approach has often been applied to certain endpoints of
particular concern for the compounds under consideration, but has not
necessarily been applied to all endpoints of each individual compound
in the category of substances.
    The Danish EPA has made extensive use of QSARs and has developed a
QSAR database that contains predicted data on more than 166,000
substances (OSPAR Commission, 2000; Ex. #69). A recent publication from
the Danish EPA reports the use of QSARs for identification of potential
persistent, bioaccumulative and toxic (PBT) and very persistent and
very bioaccumulative (vPvB) substances from among the HPV and medium-
production volume chemicals in the EU.
    OSHA is considering using a combination of chemical group
approaches to evaluate multiple chemicals with similar attributes
utilizing limited data that can be extrapolated across categories. The
Agency invites comment on how such grouping approaches have been used
to evaluate risks to worker populations.
    Question V.A.3: Are QSAR, read-across, and trend analysis useful
and acceptable methods for developing hazard information utilizing
multiple data sets for a specific group of chemicals?
    Question V.A.4: Are there other acceptable methods that can be used
to develop hazard information for multiple chemicals within a group?
    Question V.A.5: What are the advantages and disadvantages of each
method?
5. REACH: Registration, Evaluation, Authorization, and Restriction of
Chemicals in the European Union (EU)
    Safe chemical management is a universal concern. The European
Union, recognizing the need for a more integrated approach to chemical
management, adopted REACH (Registration, Evaluation, Authorization, and
Restriction of Chemicals) to address chemicals throughout their life
cycle. Although REACH applies to European Union Member States, chemical
manufacturers in other countries exporting to European countries also
have to comply with the REACH requirements to sell their products in
Europe.
    The REACH Regulation (EC) No 1907/2006 became effective on June 1,
2007, and relies on the generation and disclosure of data by
manufacturers and importers of chemicals in order to protect human
health and the environment from chemical hazards. The regulation also
established the European Chemicals Agency (ECHA) to coordinate
implementation (EC 1907/2006, 2006; Ex. #70).
    REACH establishes processes for the Registration, Evaluation,
Authorization, and Restriction of Chemicals. REACH requires
manufacturers and importers to register their chemicals and establish
procedures for collecting and assessing information on the properties,
hazards, potential risks and uses of their chemicals. The registration
process, which began in 2010, is being phased-in based on the tonnage
and hazard classification of the substances. For existing chemicals, it
is set to be completed in June 2018.
    For each chemical manufactured or imported in quantities of 1 ton
or more per year, companies must register the substance by providing a
technical dossier to ECHA. The technical dossier includes information
on: Substance identity; physicochemical properties; mammalian toxicity;
ecotoxicity; environmental fate; manufacture and use; and risk
management measures (ECHA, 2012b; Ex. #71). Non-confidential
information from the technical dossiers is published on the ECHA Web
site (ECHA, 2012c; Ex. #72).
    Companies manufacturing or importing a chemical in quantities of 10
or more tons per year must also conduct a chemical safety assessment.
This assessment includes the evaluation of: (1) Human health hazards;
(2) physicochemical hazards; (3) environmental hazards; and (4)
persistent, bioaccumulative and toxic (PBT), and very persistent and
very bioaccumulative (vPvB) potential (ECHA, 2012b; Ex. #71). If a
substance is determined to be hazardous or a PBT/vPvB, registrants must
then conduct an exposure assessment, including the development of
exposure scenario(s) (ES) and exposure estimation, and a risk
characterization that includes development of a health effects
benchmark, such as the Derived No Effect Level (DNEL).
    An exposure scenario, the main output of the exposure assessment
process, documents a set of operational conditions and risk management
measures for a specific use of a substance. A number of exposure
estimation models have been developed in the EU to help the regulated
community create these exposure scenarios. Exposure scenarios must also
be included in the Safety Data Sheets (SDS) in order to communicate
this information down the supply chain. When an extended SDS with
exposure scenarios is received by a chemical user, the exposure
scenarios must be reviewed to determine if they are applicable to the
use situation in that facility. If the exposure scenarios are
applicable, the user has 12 months to implement them. If they are not,
the user has several options to choose from to determine appropriate
controls. These options include: (1) User informing supplier of their
use, and user convincing supplier to recognize it as an "identified
use" on suppliers safety assessment; (2) user implementing the
suppliers conditions of use described in the exposure scenario of the
original/current safety assessment; (3) user substituting the substance
for another substance that is covered in a pre-existing safety
assessment; (4) user finding another supplier who does provide an
exposure scenario that covers the use of the substance; or (5) prepare
a downstream user chemical safety report. (ECHA, 2012c; Ex. #72).
    After completing the exposure assessment, registrants conduct a
risk characterization process to determine if the operational
conditions cause exposures that require risk management measures to
ensure risks of the substance are controlled. Risk characterization
consists of the comparison of exposure values derived from each
exposure scenario with their respective DNEL or an analogous health
benchmark such as Derived Minimal Effect Level (DMEL) or Predicted No
Effect Concentration (PNEC)), established by the registrant. Where no
health benchmark is available, a qualitative risk characterization is
required (ECHA, 2009; Ex. #73).
    Manufacturers and importers are required to document the
information developed during the chemical safety assessment in a
chemical safety report, which is submitted to ECHA. The report then
forms the basis for other REACH processes, including substance
evaluation, authorization, and restriction.
    ECHA and the EU Member States then evaluate the information
submitted during the registration process to examine the testing
proposals, check the quality of the registration dossiers, and evaluate
whether a substance constitutes a risk to human health or the
environment. Following the evaluation process, registrants may be
required to comply with additional actions to address concerns (i.e.,
submit further information, proceed on restriction or authorization
procedures under REACH, take actions under other legislation, etc.).
(ECHA, 2012d; Ex. #74).
    As the implementation of REACH continues, large amounts of
information will be generated by manufacturers, importers, and
downstream users throughout the registration, authorization, and
restriction processes. Some of this information is publicly available
on ECHA Web sites, and includes toxicological information, general
exposure control recommendations, and assessments of the availability
of alternatives. The generation and availability of this extensive data
on chemicals can assist OSHA, as well as U.S. employers and workers, to
further enhance chemical safety and health management by assisting in
the assessment of hazards, development of exposure control
recommendations, and selection of substitutes to help drive the
transition to safer chemicals in the workplace.
    As of July, 2013, the REACH database of registered substances is
comprised of more than 9900 substances. The database provides extensive
information to the public from dossiers prepared by chemical
manufacturers, importers, and downstream users. OSHA is interested
in determining whether some information developed and submitted under
REACH may be helpful to OSHA in its own regulatory initiatives.
Information submitted under REACH's requirements to assess chemical
risks in workplaces may be useful in developing task-based exposure
control plans, or of use in OSHA's feasibility analyses. OSHA is
participating in high-level discussions with the EU about the
feasibility of sharing these data.
    Question V.A.6: OSHA is interested in the experiences of companies
that have had to prepare chemical dossiers and submit registration
information to the European Chemicals Agency (ECHA) ECHA. In
particular, how might the approaches be used to support occupational
exposure assessments and development of use-specific risk management in
the United States?
    Question V.A.7: To what extent is information developed under REACH
used by U.S. businesses to promote product stewardship and ensure safe
use of substances and mixtures by product users?
    Question V.A.8: Should OSHA pursue efforts to obtain data from ECHA
that companies are required to provide under REACH?

B. Non-OEL Approaches to Chemical Management

    OSHA's PELs and its corresponding hierarchy of controls have been a
major focus in the fields of occupational health and industrial hygiene
for many years. Undoubtedly, occupational exposure limits (OELs), which
help reduce workers' risk of adverse health by establishing precise
targets for employers to follow, will always be an essential part of
controlling chemical exposures in workplaces. However, regardless of
whether a more effective process for updating OSHA's PELs can be
established, the rapid development of new chemical substances and
mixtures that will continue to leave workers exposed to thousands of
unregulated substances make it impractical to solely rely on OELs.
Moreover, for many of the chemicals and mixtures that have been
developed since the PELs were initially promulgated, insufficient
hazard information exists to serve as a basis for developing OELs.
While OELs generally focus on a single chemical, workers are typically
exposed to mixtures or multiple substances in the workplace. Mixed
exposures may also result in synergistic or antagonistic effects that
are rarely considered in developing OELs.
    Workplace risk assessments, and corresponding risk management
plans, should be based on an evaluation of all hazards present--OELs
established for a few chemicals among the many in the workplace
environment have diminished impact in these situations. Unlike OELs,
which are only useful in protecting workers if regular measurement and
assessment of compliance is completed, alternative risk management
approaches focus more on determining what types of controls are
required to reduce exposures without necessarily referring to
quantitative assessments of exposure to evaluate success.
    An important aspect of risk assessment and risk management is
consideration of safer alternatives, which can often result in a path
forward that is less hazardous, technically feasible, and economically
viable.
1. Informed Substitution to Safer Chemicals and Processes
    While establishing exposure limits for hazardous chemicals helps to
reduce workers' risk of adverse health effects, the process is costly,
time consuming, and does not drive the development or adoption of safer
alternatives that could best protect workers. OSHA recognizes that
ultimately, an approach to chemical management that incentivizes and
spurs the transition to safer chemicals, products, and processes in a
thoughtful, systematic way will most effectively ensure safe and
healthful conditions for workers.
    Informed substitution, the considered transition from hazardous
chemicals to safer substances or non-chemical alternatives, provides a
way of moving toward a more preventative chemical management framework.
a. Substitution in Practice
    Whenever a hazardous chemical is regulated, there is always the
potential for the chemical to be replaced with a substitute chemical or
redesigned product or process that poses new and potentially greater
hazards to workers, consumers, or the environment or results in risk-
shifting from one group to another. Regrettably, this potential has
been realized in a number of cases. For example:
     The regulation of methylene chloride by EPA, FDA, and OSHA
spurred the shift to 1-bromopropane, an unregulated neurotoxicant and
possible carcinogen, in a variety of applications, such as
refrigeration, metal cleaning, and vapor and immersion degreasing
applications, as well as in adhesive resins (Kriebel et al., 2011; Ex.
#75).
     Air quality regulations in California created a market in
the vehicle repair industry for solvent products formulated with n-
hexane, a neurotoxicant causing symptoms of peripheral neuropathy, and
hexane-acetone blends, which amplify the neurotoxic effects of n-
hexane, thus resulting in risk-shifting from the environment to workers
(Wilson et al., 2007; Ex. #76).
    While regulatory processes lacking a robust assessment of
alternatives can result in substitution that is equally detrimental to
human health or the environment, regulatory efforts that require
planning processes and provide guidance and technical assistance on
preferred alternatives can minimize risk trade-offs and protect
workers, consumers, and the environment. For example, in Massachusetts,
facilities using specific toxic chemicals in certain quantities are
required to undertake a toxics use reduction planning process. Agencies
provide various resources to encourage and facilitate the voluntary
adoption of alternatives. In the case of trichloroethylene, the
Massachusetts Office of Technical Assistance and the Toxics Use
Reduction Institute provided technical assistance, educational
workshops, a database of safer alternatives, and performance
evaluations of alternatives (Toxics Use Reduction Institute, 2011a; Ex.
#78; Toxics Use Reduction Institute, 2011b; Ex. #79; Toxics Use
Reduction Institute, 2011c; Ex. #80). Through these efforts,
Massachusetts companies reduced the use of trichloroethylene by 77
percent since 1990, moving to a number of safer alternatives in the
process (Toxics Use Reduction Institute, 2011d; Ex. #81).
    These cases demonstrate that the transition to safer chemicals,
materials, products, and processes will be best facilitated not through
restrictions or bans of chemicals, but rather through the integration
of informed substitution and guidance on preferred alternatives into
regulatory efforts.
b. Benefits of a Preference for Primary Prevention Strategies
    The reduction or elimination of a hazard at the source, as
traditionally embraced by health and safety professionals, is not only
the most reliable and effective control approach, but also provides a
number of benefits for workers and businesses.
    Preferring primary prevention strategies (i.e. elimination and
substitution) can result in the "total elimination of exposure to
hazardous chemicals, less reliance on worker compliance or equipment
maintenance for success, elimination of the potential for accidental or
non-routine overexposures, prevention of dermal exposures, and process
and environmental improvements not related to worker health"
(Roelofs et al., 2003; Ex. #82).
    Additionally, making process improvements designed to reduce or
eliminate workers' exposures to hazardous chemicals often results in
significant business improvements or savings. A 2008 study by the
American Industrial Hygiene Association (AIHA) demonstrated the
relationship between the application of the hierarchy of controls and
financial benefits. The study found that the greatest cost savings and
other benefits tended to be associated with hazard elimination and the
elimination of personal protective equipment (PPE) usage. It also
highlighted the ability of material substitution to result in very
large payoffs due to the creation of efficiencies throughout the
business process (American Industrial Hygiene Association, 2008; Ex.
#83). For example:
     A foundry making automatic diesel engine blocks enhanced
and aggressively enforced a purchasing specification program to
eliminate supplied scrap metal contaminated with lead. By eliminating
lead from its supply chain, the company not only achieved high levels
of employee protection, but also enhanced the quality of its products
and realized nearly $20 million in savings for the facility.
     An aircraft manufacturing company, struggling to comply
with the OSHA PEL for hexavalent chromium, transitioned from chromate-
based primers to non-chromate based primers, resulting not only in the
elimination of worker exposure to chromate dusts from rework sanding,
but also in quality improvements of its products, increased customer
satisfaction, productivity gains, avoidance of costly changes to their
exhaust ventilation system, and a savings of $504,694 over the 5-year
duration of the project.
c. Informed Substitution
    In order to truly protect workers from chemical hazards, it is
important that OSHA not only develop health standards for hazardous
chemicals, but also understand alternatives to regulated chemicals and
support a path forward that is less hazardous, technically feasible,
and economically viable. Informed substitution provides a framework for
meeting this goal.
    As previously described, informed substitution is the considered
transition from a potentially hazardous chemical, material, product, or
process to safer chemical or non-chemical alternatives. The goals of
informed substitution are to minimize the likelihood of unintended
consequences, which can result from a precautionary switch away from a
hazardous chemical without fully understanding the profile of potential
alternatives, and to enable a course of action based on the best
information that is available or can be estimated. Informed
substitution approaches focus on identifying alternatives and
evaluating their health, safety, and environmental hazards, potential
trade-offs, and technical and economic feasibility.
    Substitution is not limited to substitution of one chemical with
another. It can also occur at the production process or product level.
At the product level, substitution may involve a design change that
takes advantage of the characteristics of new or different materials. A
chemical process design change may eliminate several production steps
thereby avoiding or reducing the use of high hazard chemicals. In some
cases, a particular chemistry or the function it serves may be
determined to be unnecessary.
    As implementation of chemical substitution and product and process
changes can be quite complicated, a variety of processes, tools, and
methods are critical to achieving informed substitution.
    Substitution planning, similar to facility planning for pollution
prevention and source reduction, establishes practical steps for
evaluating substitution as a workplace risk reduction measure. This
type of planning process supports informed substitution by encouraging
chemical users to: Systematically identify hazardous chemicals; set
goals and priorities for the elimination or reduction of hazardous
chemicals; evaluate alternatives; identify preferred alternatives; and
promote the adoption of identified alternatives.
    Alternatives assessment is a process of identifying and comparing
potential chemical and non-chemical alternatives that could replace
chemicals or technologies of concern on the basis of their hazards,
performance, and economic viability. A variety of alternatives
assessment processes have been developed to date (Lavoie et al., 2010;
Ex. #84; Toxics Use Reduction Institute, 2006; Ex. #85; Rossi et al.,
2006; Ex. #86; Raphael et al., 2011; Ex. #87). Various tools and
methods have been developed to evaluate hazard, performance, and cost
when assessing alternatives. For example, comparative chemicals hazard
assessments compare potential alternatives based on a variety of hazard
endpoints in order to select a safer alternative. Some examples of
comparative chemicals hazard assessment tools include the GreenScreen
(Clean Production Action, 2012; Ex. #88) and Design for the Environment
(DfE) Safer Product Labeling Program (U.S. EPA, 2011a; Ex. #89). Other
existing methods for chemical comparison include the Column Model
(Institut f[uuml]r Arbeitsschutz der Deutschen Gesetzlichen
Unfallversicherung, 2011; Ex. #90) and QuickScan (Netherlands Ministry
of Infrastructure and the Environment, 2002; Ex. #91). Tools and
methods for evaluating performance and cost attributes, while less well
developed, are also critical for the selection of a preferred
alternative.
d. Substitution at OSHA
    Substitution is not new for OSHA. Historically, OSHA attempted to
encourage substitution by setting a "no occupational exposure level"
for certain potential carcinogens where suitable substitutes that are
less hazardous to humans existed for particular uses (45 FR 5257-58;
Ex. #92). Although this requirement was never fully implemented, the
final rule detailed a process for the Agency to analyze the feasibility
of substitutes, which required the consideration of: (1) the safety of
the substitute, including the comparative acute and chronic toxicity of
the carcinogenic chemical and the substitute, and other relevant
factors, such as environmental factors; (2) the technical feasibility
of the substitute, including its relative effectiveness; and (3) the
economic cost of substitution (45 FR 5258; Ex. #92, 29 CFR 1990.111(k);
Ex. #93, see also 1990.132(b)(6); Ex. #94, 1990.146(k); Ex. #95).
    OSHA health standards also identify substitution as a preferred
exposure control. For example, in the 1989 Air Contaminants Standard,
the Agency refers to substitution, when properly applied, as "a very
effective control technique" and "the quickest and most effective
means of reducing exposure" (54 FR 2727, 2789; Ex. #7). In addition,
the Agency's respiratory protection standard mandates the use of
accepted engineering control measures, including the substitution of
less toxic materials, as far as feasible, before using respirators to
control occupational diseases caused by breathing contaminated air (29
CFR 1910.134(a); Ex. #96). Despite this, when complying with PELs and
other health standards in practice, employers are required to select
and implement administrative or engineering controls before using
personal protective equipment, but are not specifically required or
encouraged to consider elimination or substitution before other
engineering or administrative controls. (See 29 CFR 1910.1000(e); Ex. #97).
Thus, substitution may be often overlooked in favor of other approaches,
such as ventilation and isolation, when employers are controlling exposures
to hazardous chemicals.
    OSHA also considers substitution during the development of PELs.
While OSHA does not solely rely on substitution to make its required
feasibility findings (62 FR 1494, 1576; Ex. #98; 71 FR 10099, 10260;
Ex. #99), the Agency, as part of PEL rulemaking efforts, develops and
evaluates information about substitution in its technological and
economic feasibility analysis, highlighting options available for
eliminating or reducing the regulated chemical's use in various
industries and applications. For example, the feasibility analysis for
methylene chloride describes numerous substitute chemicals and
processes, including a detailed table of substitute paint removal
methods for 16 applications, and evaluates the relative risks for seven
of the more common substitutes for methylene chloride (OSHA, 1996; Ex.
#100). However, the analysis of substitutes has varied widely from
regulation to regulation. For example, the feasibility analysis for
hexavalent chromium identifies specific substitute chemicals and
processes in many industries, but does not discuss the health or safety
hazards of the substitutes (OSHA, 2006a; Ex. #101), while the
feasibility analysis for formaldehyde includes only a mention of the
availability of one identified substitute for a few industry sectors
(OSHA, 1987; Ex. #102) and the feasibility analysis for ethylene oxide
does not contain any discussion of substitutes (OSHA, 1984; Ex. #103).
    OSHA has also included information on substitutes in a variety of
non-regulatory documents. New information about available substitutes
and substitution trends is included in lookback reviews of existing
standards conducted by the Agency (e.g., lookback review of the
ethylene oxide standard, lookback review of the methylene chloride
standard) (OSHA, 2005; Ex. #104; OSHA, 2010; Ex. #105). In some cases,
OSHA has also developed information on substitution, even where a PEL
has not been established. For example, the OSHA guidance document on
the best practices for the safe use of glutaraldehyde in health care
includes information about drop-in replacements and alternative
processes available to reduce or eliminate the use of the chemical
(OSHA, 2006b; Ex. #106).
    In October 2013, OSHA launched an effort to encourage employers,
workers, and unions to proactively reduce the use of hazardous
chemicals in the workplace and achieve chemical use that is safer for
workers and better for business. As part of this effort, the Agency
developed a web toolkit that guides employers and workers in any
industry through a seven-step process for transitioning to safer
chemicals (OSHA, 2013a; Ex. #107). Each step contains information,
resources, methods, and tools that will help users eliminate hazardous
chemicals or make informed substitution decisions in the workplace by
finding a safer chemical, material, product, or process.
e. Possible Opportunities for Integrating Informed Substitution
Approaches Into OSHA Activities
    There are a variety of existing regulatory and non-regulatory
models for incorporating informed substitution into chemical management
activities. The following are some examples of entities that have
developed and utilized informed substitution approaches as part of
regulatory efforts; guidance and policy development; education,
training, and technical assistance activities; and data development and
research efforts.
i. Models for Regulatory Approaches
    Some regulations and voluntary standards require risk reduction
through the implementation of a hierarchy of controls that clearly
delineates elimination and substitution as preferred options to be
considered and implemented, where feasible, before other controls. For
example, the ANSI/AIHA Z10-2005 standard for Occupational Health and
Safety Management Systems, a voluntary national consensus standard,
requires organizations to implement and maintain a process for
achieving feasible risk reduction based upon the following preferred
order of controls: A. Elimination; B. Substitution of less hazardous
materials, processes, operations, or equipment; C. Engineering
controls; D. Warnings; E. Administrative Controls; and F. Personal
protective equipment (ANSI/AIHA Z10-2005, 2005; Ex. #108). European
Union Directives 98/24/EC and 2004/37/EC require employers to eliminate
risks by substitution before implementing other types of protection and
prevention measures (98/24/EC, 1998; Ex. #109, 2004/37/EC, 2004; Ex.
#110).
    Some existing laws require firms to undertake planning processes
for the reduction of identified hazardous chemicals. For example, the
Massachusetts Toxics Use Reduction Act requires entities that use
listed hazardous chemicals in certain quantities to undertake a
planning process for reducing the use of those chemicals (Massachusetts
Department of Environmental Protection, n.d.; Ex. #77).
    Existing regulations in the European Union place a duty on
employers to replace the use of certain hazardous chemicals with safer
substitutes, if technically possible. For example, Directive 2004/37/EC
requires the substitution of carcinogens and mutagens with less harmful
substances where technically feasible (2004/37/EC, 2004) and Directive
98/24/EC requires employers to ensure that risks from hazardous
chemical agents are eliminated or reduced to a minimum, preferably by
substitution (98/24/EC, 1998; Ex. #109).
    Other regulations require the use of acceptable substitutes where
the uses of certain hazardous chemicals are phased-out. This type of
approach is currently implemented by U.S. EPA in the context of
phasing-out ozone depleting substances. The Clean Air Act requires that
these substances be replaced by others that reduce risks to human
health and the environment. Under the Significant New Alternatives
Policy (SNAP) program, EPA identifies and publishes lists of acceptable
and unacceptable substitutes for ozone-depleting substances (Safe
Alternatives Policy, 2011; Ex. #111).
    Some chemical management frameworks require the assessment of
substitutes before making decisions to limit or restrict the use of a
hazardous chemical. For example, the European Union REACH Regulation
(Registration, Evaluation, Authorization and Restriction of Chemicals)
requires that an analysis of alternatives, the risks involved in using
any alternative, and the technical and economic feasibility of
substitution be conducted during applications of authorization for
substances of very high concern (EC 1907/2006, 2006; Ex. #70).
    Other efforts to spur the transition to safer chemicals, products,
and processes are based on the development of criteria-based standards
for functions or processes that rely on hazardous chemicals. For
example, the EPA DfE Safer Product Labeling Program is a nonregulatory
program that recognizes safe products using established criteria-based
standards. In order to receive DfE recognition, all chemicals in a
formulated product must meet Master Criteria (i.e., toxicological
thresholds for attributes of concern, including: acute mammalian toxicity;
carcinogenicity; genetic toxicity; neurotoxicity; repeated dose toxicity;
reproductive and developmental toxicity; respiratory sensitization; skin
sensitization; environmental toxicity and fate; and eutrophication), as
well as relevant functional-class criteria (i.e., additional toxicological
thresholds for attributes of concern for surfactants, solvents, direct-release
products, fragrances, and chelating and sequestering agents), established by
the EPA (U.S. EPA, 2011a; Ex. #89).
    While there are a number of ways in which OSHA could consider
integrating substitution and alternatives assessment into its
regulatory efforts, the Agency, in order to promulgate any such
standard, would need to make the significant risk, technological
feasibility, and economic feasibility findings required under the OSH
Act. However, even without regulation, it is important to consider
voluntary models for incorporating informed substitution into chemical
management activities.
ii. Models for Guidance Development
    Some entities have developed guidance to promote the transition to
safer alternatives. The European Union, in order to support legislative
substitution mandates, developed guidance on the process of
substitution, including setting goals, identifying priority chemicals,
evaluating substitutes, selecting safer alternatives, and implementing
chemical, material, and process changes. The guidance establishes and
describes a seven step substitution framework, providing workplaces
with a systematic process for evaluating chemical risk and identifying
chemicals that could or should be substituted (European Commission,
2012; Ex. #113). The steps include: Assessing the current level of
risk; deciding on risk reduction needs; assessing the margins of
change; looking for alternatives; checking the consequences of a
change; deciding on change; and deciding on how and when to implement
change.
    Similarly, the German Federal Institute for Occupational Safety and
Health (BAuA) established guidance to support the employer's duty, as
mandated in the German Hazardous Substances Ordinance, to evaluate
substitutes to hazardous substances and implement substitution where
less hazardous alternatives are identified (German Federal Institute
for Occupational Safety and Health, 2011; Ex. #114). The guidance, TRGS
600, includes a framework for identifying and evaluating substitutes
and establishes criteria for assessing and comparing the health risks,
physicochemical risks, and technical suitability of identified
alternatives (German Federal Institute for Occupational Safety and
Health, 2008; Ex. #115).
    The German Environment Agency has also developed guidance on
sustainable chemicals. The guide assists manufacturers, formulators,
and end users of chemicals in the selection of sustainable chemicals by
providing criteria to distinguish between sustainable and non-
sustainable substances (German Environment Agency, 2011; Ex. #116).
    OSHA considered developing guidance on safer substitutes to
accompany individual chemical exposure limit standards in its 2010
regulatory review of methylene chloride. Due to the increased use of
other hazardous substitutes after methylene chloride was regulated in
1998, the Agency considered establishing guidance recommending that
firms check the toxicity of alternatives on the EPA and NIOSH Web sites
before using a substitute (OSHA, 2010; Ex. #105).
iii. Models for Education, Training, and Technical Assistance
    Other entities have developed outreach, training, and technical
assistance efforts for substitution planning and the assessment of
substitutes for regulated chemicals. The Massachusetts Toxics Use
Reduction Act, which established a number of structures to assist
businesses, provides a good example of such efforts. The Massachusetts
Office of Technical Assistance and Technology (OTA) provides compliance
assistance and on-site technical support that helps facilities use less
toxic processes and boost economic performance. The Massachusetts
Toxics Use Reduction Institute provides training, conducts research,
and performs alternatives assessments in order to educate businesses on
the existence of safer alternatives and promote the on-the-ground
adoption of these alternatives. Toxics Use Reduction Planners (TURPs),
certified by the Massachusetts Department of Environmental Protection
(MA DEP), prepare, write and certify the required toxics use reduction
plans and are continually educated about best practices in toxics use
reduction. Taken together, these services provide a robust resource for
regulated businesses on the transition to safer alternatives
(Massachusetts Department of Environmental Protection, n.d.; Ex. #77).
iv. Models for Data Development
    Several efforts, at both the federal and international levels,
attempt to support the transition to safer alternatives through
research and data development. For example, EPA, in collaboration with
the non-governmental organization GreenBlue and industry stakeholders,
jointly developed a database of cleaning product ingredient chemicals
(surfactants, solvents, fragrances, and chelating agents) that meet
identified environmental and human health criteria (GreenBlue, 2012;
Ex. #117). In Spain, the Institute of Work, Environment, and Health
(ISTAS) has developed a database that is a repository of information on
substitute chemicals. The database can be searched for chemical
substances, uses/products, processes, or sectors to display information
on substitutes and hazards associated with those substitutes (ISTAS,
2012; Ex. #118). In addition, the European Union SUBSPORT project has
begun to create a Substitution Support Portal, a state-of-the-art
resource on safer alternatives to the use of hazardous chemicals. The
resource is intended to provide not only information on alternative
substances and technologies, but also tools and guidance for substance
evaluation and substitution management (SUBSPORT, 2012; Ex. #119).
    Other efforts focus on the completion of alternatives assessments
for priority chemicals and uses. Currently, EPA's Design for the
Environment Program, as well as the Massachusetts Toxics Use Reduction
Institute, has conducted alternatives assessments for priority
chemicals and functional uses, making this information publicly
available in the process (U.S. EPA, 2012c; Ex. #120; Toxics Use
Reduction Institute, 2006; Ex. #85).
    In addition, some research efforts attempt to fill data gaps with
regards to the toxicological properties of existing chemicals. While
some efforts to conduct toxicity testing for chemicals is taking place
at the federal level (U.S. EPA, 2011b; Ex. #121, U.S. EPA, 2012d; Ex.
#122), there have not been systematic efforts to conduct targeted
toxicology studies for specific substitutes of interest.
    Question V.B.1: To what extent do you currently consider
elimination and substitution for controlling exposures to chemical
hazards?
    Question V.B.2: What approaches would most effectively encourage
businesses to consider substitution and adopt safer substitutes?
    Question V.B.3: What options would be least burdensome to industry,
especially small businesses? What options would be most burdensome?
    Question V.B.4: What information and support do businesses need to
identify and transition to safer alternatives? What are the most
effective means to provide this information and support?
    Question V.B.5: How could OSHA leverage existing data resources to
provide necessary substitution information to businesses?
v. Effectively Implementing Informed Substitution Approaches
    The goals of informed substitution cannot be achieved without the
development and application of tools and methods for identifying,
comparing, and selecting alternatives. Existing tools and methods range
in complexity, from quick screening tools to detailed comparative
hazard assessment methodologies to robust frameworks for evaluating
alternatives based on hazard, performance, and economic feasibility.
Illustrative examples, which represent the range of tools available,
are described below.
    Some assessment tools provide methods for rapid evaluation of
chemical hazards based on readily available information. These types of
tools are critical for small and medium-sized businesses, which often
lack resources and expertise to evaluate and compare chemical hazards.
In the state of Washington, the Department of Ecology (DOE) has
developed the Quick Chemical Assessment Tool (QCAT) to allow businesses
to identify chemicals that are not viable alternatives to a chemical of
concern by assigning an appropriate grade for the chemical based on
nine high priority hazard endpoints (Washington Department of Ecology,
2012; Ex. #123). Similarly, the Institute for Occupational Safety and
Health of the German Federation of Institutions for Statutory Accident
Insurance and Prevention (IFA) developed the Column Model as a tool for
businesses to evaluate chemicals based on six hazard categories using
information obtained from chemical safety data sheets (IFA, 2011; Ex.
#90).
    Other existing tools provide more detailed methodologies for
conducting a comparative hazard assessment, which require greater
expertise, data, and resources to complete. The GreenScreen, created by
Clean Production Action, provides a methodology for evaluating and
comparing the toxicity based on nineteen human and environmental hazard
endpoints, assigning a level of concern of high, moderate, or low for
each endpoint based on various established criteria (Clean Production
Action, 2012; Ex. #88).
    A number of robust frameworks have also been developed to assess
the feasibility of adopting alternatives for hazardous chemicals based
on environmental, performance, economic, human health, and safety
criteria. The Massachusetts Toxics Use Reduction Institute developed
and implemented a methodology for assessing alternatives to hazardous
chemicals based on performance, technical, financial, environmental,
and human health parameters (TURI, 2006; Ex. #85). Similarly, the U.S.
EPA DfE program has also developed and implemented an alternatives
assessment framework to characterize alternatives based on the
assessment of chemical hazards as well as the evaluation of
availability, functionality, economic, and life cycle considerations
(Lavoie et al., 2010; Ex. #84, U.S. EPA, 2012c; Ex. #120).
    Although some tools and methods exist, as discussed above, further
research and development in this area is critical for the effective
implementation of informed substitution.
    Question V.B.6: What tools or methods could be used by OSHA and/or
employers to conduct comparative hazard assessments? What criteria
should be considered when comparing chemical hazards?
    Question V.B.7: What tools or methods could be used by OSHA and/or
employers to evaluate and compare the performance and cost attributes
of alternatives? What criteria should be considered when evaluating
performance and cost?
2. Hazard Communication and the Globally Harmonized System (GHS)
    OSHA promulgated its Hazard Communication Standard (HCS) (29 CFR
1910.1200; Ex. #124) in 1983 to require employers to obtain and provide
information to their employees on the hazards associated with the
chemicals used in their workplaces. After thirty years of
implementation, the HCS has resulted in extensive information being
disseminated in American workplaces through labels on containers,
safety data sheets (SDSs), and worker training programs.
    On March 26, 2012, OSHA published major modifications to the HCS.
(77 FR 17574-17896; Ex. #125). These modifications are being phased in
over several years, and will be completely implemented in June 2016.
Referred to as HazCom 2012, the revised rule incorporates a new
approach to assessing the hazards of chemicals, as well as conveying
information about them to employees. The revised rule is based on the
United Nations' Globally Harmonized System for the Classification and
Labeling of Chemicals (GHS), which established an international,
harmonized approach to hazard communication.
    The original HCS was a performance-oriented rule that prescribed
broad rules for hazard communication but allowed chemical manufacturers
and importers to determine how the information was conveyed. In
contrast, HazCom 2012 is specification-oriented. Thus, while the HCS
requires chemical manufacturers and importers to determine the hazards
of chemicals, and prepare labels and safety data sheets (SDSs), HazCom
2012 goes further by specifying a detailed scheme for hazard
classification and prescribing harmonized hazard information on labels.
In addition, SDSs must follow a set order of information, and the
information to be provided in each section is also specified.
    Hazard classification means that a chemical's hazards are not only
identified, they are characterized in terms of severity of the effect
or weight of evidence for the effect. Thus, the assessment of the
hazard involves identifying the "hazard class" into which a chemical
falls (e.g., target organ toxicity), as well as the "hazard
category"--a further breakdown of the hazardous effect generally based
on either numerical cut-offs, or an assessment of the weight of the
evidence. For target organ toxicity, for example, chemicals for which
there is human evidence of an effect are likely to be classified under
Category 1, the most hazardous category, thus indicating the highest
classification for the effect. If the only data available are animal
studies, the chemical may fall in Category 2--still potentially
hazardous to humans, but lower in terms of the weight of evidence for
the effect. Table-I illustrates how such a chemical hazard
classification may be assigned by hazard class and hazard category

[GRAPHIC] [TIFF OMITTED] TP10OC14.001

    The process of classifying chemicals under HazCom 2012 means that
all chemicals will be fully characterized as to their hazards, as well
as degree of hazardous effect, using a standardized process with
objective criteria. Thus, OSHA could use this system to select certain
hazard classes and categories to set priorities. For example, the
Agency could decide to identify substances that are characterized as
Class 1 Carcinogens or as Reproductive Toxicants as its priorities.
Then chemicals that fall into those hazard categories could be further
investigated to determine other relevant factors, such as numbers of
employees exposed, use of the chemical, risk assessment, etc. The
HazCom 2012 information could lead to a more structured and consistent
priority system than previously attempted approaches. (Ex. #126) OSHA
could also investigate whether the hazard categories lend themselves to
establishing regulatory provisions for hazard classes and categories
rather than for individual substances. The availability of specific
hazard categorization for chemicals could allow this to be done on a
grouping basis--either in regulation, or in guidance.
    Once a chemical is placed into a hazard class and hazard category,
HazCom 2012 (and the GHS) specifies the harmonized information that
must appear on the label. Referred to as "label elements," these
include a pictogram, signal word, hazard statement(s), and
precautionary statement(s). In addition, the label must have a product
identifier and supplier contact information. The use of standardized
label elements will help to ensure consistency and comprehensibility of
the information, which will make HazCom 2012 more effective in terms of
conveying information to employees and employers. The approach taken in
the GHS strengthens the protections of the OSHA HCS in several ways,
and introduces the possibility of the Agency using the information
generated under HazCom 2012 to help frame a more comprehensive approach
to ensuring occupational chemical safety and health.
3. Health Hazard Banding
    "Health hazard banding" can be defined as a qualitative framework
to develop occupational hazard assessments given uncertainties caused
by limitations in the human health or toxicology data for a chemical or
other agent. Health hazard banding presumes it is possible to group
chemicals or other agents into categories of similar toxicity or hazard
characteristics.
    Health hazard banding assigns chemicals with similar toxicities
into hazard groups (or bands. The occupational health professional can
use this classification or hazard band, along with information on
worker exposures to the substance, to do exposure risk assessment.
Hazard banding, along with exposure information, is a useful risk
assessment tool, particularly in situations where toxicity data are
sparse. Hazard banding can also aid in the prioritization and hazard
ranking of chemicals in the workplace. NIOSH is working with OSHA and a
variety of stakeholder groups (federal agencies, industry, labor
organizations, and professional associations) to develop guidance on
establishing the technical criteria, decision logic, and minimum
dataset for the hazard band process.
4. Occupational Exposure Banding
    NIOSH has proposed an approach, occupational exposure banding,
which would sort chemicals into five bands (A through E), with each band
representing a different hazard level. Chemicals with the lowest toxicity
would be grouped in Band A, while the moist toxic chemicals would be grouped
in Band E. The proposed process includes a three-tiered evaluation system
based on the availability of toxicological data to define a range of
concentrations for controlling chemical exposures. A Tier 1 evaluation relies
on hazard codes and categories from GHS, and intended for chemicals for
which little information exists. Therefore, a chemical in Band D or E
in the Tier 1 process is a bad actor and should be targeted for
elimination and or substitution. Tier 2 and 3 require professional
expertise. Once NIOSH completes their validation work of the three
tiers, they plan to develop tools to facilitate evaluating hazard data
and assigning chemicals to hazard bands as well as educational
materials for health and safety professionals, managers, and workers.
(Exs. #127 & #128)
5. Control Banding
    Control banding is a well-established approach of using the hazard
statements from a label and/or safety data sheet (SDS) to lead an
employer to recommended control measures. This approach has been used
successfully in a number of countries, particularly in Europe where
such as system of hazard classification has been in use for some time.
HazCom 2012 opens up the possibility that control banding can be
further developed and refined in the U.S., either as guidance or
regulatory provisions. It is a particularly useful way to provide
information for small businesses to effectively control chemicals
without necessarily going through the process of exposure monitoring
and other technical approaches to ensuring compliance. It also will
give employers better information to conduct risk assessments of their
own workplaces, and thus select better control measures.
    Health hazard banding can be used in conjunction with control
banding to use the information available on the hazard to guide the
assessment and management of workplace risks. In fact, health hazard
banding is the first step in the control banding process. Control
banding determines a control measure (for example dilution ventilation,
engineering controls, containment, etc.) based on a range or "band"
of hazards (such as skin/eye irritant, very toxic, carcinogenic, etc.),
and exposures (small, medium, or large exposure). This approach is
based on the fact that there are a limited number of control
approaches, and that many chemical exposure problems have been met and
solved before. Control banding uses the solutions that experts have
developed previously to control occupational chemical exposures, and
suggests them for other tasks with similar exposure situations. It
focuses resources on exposure controls, and describes how strictly a
risk needs to be managed.
    Control banding is a more comprehensive qualitative risk
characterization and management strategy that goes further in assigning
prescribed control methods to address chemical hazards. It is designed
to allow employers to evaluate the need for exposure control in an
operation and to identify the appropriate control strategy given the
severity of the hazard present and magnitude of exposure. The strength
of control banding is that it is based on information readily available
to employers on safety data sheets (SDSs), without the need for
exposure measurements or access to occupational health expertise
(except in certain circumstances). Control banding involves not only
the grouping of workplace substances into hazard bands (based on
combinations of hazard and exposure information) but also links the
bands to a suite of control measures, such as general dilution
ventilation, local exhaust ventilation, containment, and use of
personal protective equipment (PPE).
    Under control banding, one must consider the chemical's hazardous
properties, physical properties, and exposure potential in order to
determine the level of exposure control desired. The criteria used for
categorizing chemicals include hazard information such as flammability,
reactivity, and the nature of known health effects. These
characteristics are associated with defined hazard phrases (e.g.,
"Causes severe skin burns and eye damage" or "Causes liver damage,"
or "Reproductive hazard"). These standardized phrases have been
familiar in the EU as "R-phrases" and are found on SDSs.
    Different hazard bands exist along a continuum ranging from less
hazardous chemicals to more hazardous chemicals. Once the appropriate
hazard group has been determined from the hazard statements (e.g.,
"Hazard Group B"), exposure potential is evaluated based on the
quantity in use, volatility (for liquids), or particulate nature (for
solids). After evaluating these properties and categorizing the
chemical into hazard and exposure bands, the chemicals are matched,
based on their band categorization, to the appropriate control
strategy, with more stringent controls applied for substances that are
placed in high-toxicity bands.
    The Control of Substances Hazardous to Health (COSHH) guidance
issued by the Safety Executive (HSE) of the United Kingdom is one model
of control banding (Health and Safety Executive, 2013; Ex. #129). Under
the 2002 COSHH regulation, employers must conduct a risk assessment to
decide how to prevent employees from being exposed to hazardous
substances in the workplace. COSHH principles first require that
exposure is prevented by employers, to the extent possible, by means
of:
     Changing the way tasks are carried out so that exposures
aren't necessary anymore;
     Modifying processes to cut out hazardous by-products or
wastes; or
     Substituting a non-hazardous or less hazardous substance
for a hazardous substance with new substances (or use the same
substance in a different form) so that there is less risk to health.
    If exposures to hazardous substances cannot be prevented entirely,
then COSHH requires employers to adequately control them (Control of
Substances Hazardous to Health Regulations, 2002; Ex. #130).
Recognizing that many small employers may not have access to the
required expertise, and also to reduce the need for a professional and
to promote consistency in the assessment process, the HSE developed an
approach to assessment and control of chemical hazards using control
banding methodologies spelled out in the 2002 regulation. This control
banding approach is described in detail in COSHH Essentials. Employers
may use the guidance spelled out in the COSHH Essentials guide to
determine the appropriate control approach for the chemical hazard in
question. Each control approach covers a range of actions that work
together to reduce exposure: (1) General Ventilation, (2) Engineering
Controls, (3) Containment, and lastly, (4) Special--a scenario where
employers should seek expert advice to select appropriate control
measures.
    The first step outlined under the COSHH Essentials guidance is to
consult the safety data sheet for each chemical in use. Employers must
record the date of assessment, the name of the chemical being assessed,
the supplier of the chemical, and the task(s) for which the chemical is
used.
    Step two involves the determination of the health hazard. Employers
ascertain the hazard by assessing the possible health effects from the
hazard statements provided on the SDS, the amount in use, and the
dustiness or volatility of the chemical in use.
Employers reference the hazard statements found on chemical safety data
sheets against a table of COSHH hazard groups in order to categorize
them into the appropriate hazard group ("A" through "E", and
possibly "S"). Chemicals in Group A tend to be regarded as less
harmful and may, for example, cause temporary irritation. Chemicals in
Group E are the most hazardous and include known carcinogens. Group S
encompasses substances that have special considerations for damage
caused via contact with the eyes or skin.
    Additionally, Step two requires employers to make some
determinations about the quantity and physical state of chemicals in
use. They must decide if the amount of chemical in use would be
described as "small" (grams or milliliters), "medium" (kilograms or
liters), or "large" (tons or cubic meters). When in doubt, COSHH
Essentials principles encourage employers to err on the side of the
larger quantity in making their determination. Additionally, the
physical state of chemicals effect how likely they are to get into the
air and this affects the control approach to be utilized. For solids,
COSHH Essentials guides employers to make a determination of either
"Low", "Medium", or "High" dustiness based upon visible criteria
observed during the use of these chemicals. Employers may also use
look-up tables provided in the COSHH Essentials guide to make a
determination of whether liquids have "low", "medium", or "high"
volatility based upon the chemical's boiling point and ambient or
process operating temperatures.
    In Step three of the COSHH Essentials guide, employers identify the
appropriate control approach. Tables provided by the COSHH Essentials
guide show the control approaches for hazard groups "A" through "E"
according to quantity of chemical in use and its dustiness/volatility.
Table-II illustrates how the control approaches are assigned. The
control approaches referred to by number in the table are: 1) General
Ventilation, 2) Engineering Control, 3) Containment, and 4) Special.
(Health and Safety Executive, 2009; Ex. #131).
[GRAPHIC] [TIFF OMITTED] TP10OC14.002
    Additionally, the COSHH Essentials guide provides detailed control
guidance sheets for a range of common tasks. Consultation of these
task-specific guidance sheets constitutes Step four under COSHH
Essentials. Step five of COSHH Essentials involves the employer
deciding on how best to implement control measures as prescribed. COSHH
Essentials principles also stress the importance of employers reviewing
their assessments regularly, especially if there is a significant
change in workplace processes or environment. Employers are encouraged
to incorporate exposure level monitoring, health surveillance, and
relevant training.
    A number of European Union nations (e.g., United Kingdom, Germany,
France, Netherlands, Norway, and Belgium) and Asian nations (Singapore
and Korea) already utilize control banding methods comparable to COSHH
Essential methods for management of a variety of chemical exposures in
the workplace.
    A number of studies have been conducted to assess the validity of a
control banding model for control of exposure to chemicals. Jones and
Nicas (2006; Ex. #132) reviewed the COSHH Essentials model for hazard-
banding in vapor degreasing and bag-filling tasks. Their study showed
that the model did not identify adequate controls in all scenarios with
approximately eighteen percent of cases leaving workers potentially
under-protected. However, in a similar study, Hashimoto et al. (2007;
Ex. #133) showed that hazard-banding tended to overestimate the level
of control and therefore was more protective. In 2011, Lee et al. (Ex.
#134) found that for a paint manufacturing facility using mixtures of
chemicals with different volatilities, exposure to the chemicals with
higher volatility had a higher likelihood to exceed the predicted
hazard-band. Lee also recommended further research for more precise
task identification to better enable implementation of task-specific
control measures.
    NIOSH provides a thorough review and critical analysis of the
concepts, protective nature, and potential barriers to implementation
of control banding programs (NIOSH, 2009; Ex. #135). NIOSH concluded
that control banding can be used effectively for performing workplace
risk assessments and implementing control solutions for many, but not
all occupational hazards. Additionally, NIOSH found that while in some
situations in which control banding cannot provide the precision and
accuracy necessary to protect worker health, and in some cases control
banding will provide a higher level of control than is necessary.
    COSHH Essentials and other control banding concepts developed in
Europe were based initially on the European Union's pre-GHS
classification and labeling system. Since the European Union has
adopted the GHS in its classification and labeling rules, these risk
phrases will no longer be available. Control banding approaches are now
based on the hazard statements in the GHS. OSHA's adoption of the GHS
to modify the HCS opens up the opportunity to use a control banding
approach to chemical exposures in American workplaces based on the
hazard classification system. This would be an alternative to focusing
on PELs that could achieve the goal of risk management for many
chemicals and operations in workplaces.
    OSHA is interested in exploring how it might employ these non-OEL
approaches in a regulatory framework to address hazardous substances
where the available hazard information does not yet provide a
sufficient basis for the Agency's traditional approach of using risk
assessment to establish a PEL. OSHA believes that a hazard banding
approach could allow the Agency to establish specification requirements
for the control of chemical exposures more efficiently, offering
additional flexibility to employers, while maintaining the safety and
health of the workforce. Although health hazard banding and control
banding show some promise as vehicles for providing guidance to
occupational health professionals for controlling exposures to workers,
their use in a regulatory scheme presents challenges. For example, the
agency would need to consider how, if it were to require such
approaches, the OSH Act's requirement that standards that reduce
significant risk to the extent feasible might be satisfied.
    OSHA is also interested in exploring the development of voluntary
guidelines for incorporation of control banding into safety and health
management programs in U.S. workplaces. These efforts might include the
development and dissemination of compliance assistance materials
(publications, safety and health topic Web pages, computer software and
smartphone apps, e-Tools) as well as consultation services to assist
small businesses.
    Question V.B.8: How could OSHA use the information generated under
HazCom 2012 to pursue means of managing and controlling chemical
exposures in an approach other than substance-by-substance regulation?
    Question V.B.9: How could such an approach satisfy legal
requirements to reduce significant risk of material impairment and for
technological and economic feasibility?
    Question V.B.10.: Please describe your experience in using health
hazard and/or control banding to address exposures to chemicals in the
workplace.
    Question V.B.11.: Are additional studies available that have
examined the effectiveness of health hazard and control banding
strategies in protecting workers?
    Question V.B.12.: How can OSHA most effectively use the concepts of
health hazard and control banding in developing health standards?
    V.B.13.: How might OSHA use voluntary guidance approaches to assist
businesses (particularly small businesses) with implementing the
principles of hazard banding in their chemical safety plans? Could the
GHS chemical classifications be the starting point for a useful
voluntary hazard banding scheme? What types of information, tools, or
other resources could OSHA provide that would be most effective to
assist businesses, unions, and other safety and health stakeholders
with operationalizing hazard banding principles in the workplace?
    Question V.B.14.: Should OSHA consider greater use of specification
standards or guidance as an approach to developing health standards? If
so, for what kinds of operations are specification approaches best
suited?
6. Task-based Exposure Assessment and Control Approaches
    Job hazard analysis is a safety and health management tool in which
certain jobs, tasks, processes or procedures are evaluated for
potential hazards or risks, and controls are implemented to protect
workers from injury and illness. Likewise, task-based assessment and
control is a system that categorizes the task or job activity in terms
of exposure potential and requirements for specific actions to control
the exposure are implemented, regardless of occupational exposure
limits. Tasks are isolated from the deconstruction of a larger process
that is in turn part of an overall operation or project in an
industrial setting. As industrial engineering explores the optimization
of complex processes or systems through an evaluation of the integrated
system of people, equipment, materials, and other components, the task-
based system attempts to evaluate work activities to define uniform
exposure scenarios and their variables and establish targeted control
strategies.
    Task-based exposure potential can be defined using readily
available data including process operating procedures, task observation
and analysis, job activity description, chemical inventory and toxicity
information (hazard communication), historical exposure data, existing
exposure databases, employee surveys, and current exposure data. Based
on this exposure assessment, the task is matched with specific
requirements for exposure control. Control specifications can draw on a
broad inventory of exposure controls and administrative tools to reduce
and prevent worker exposure to the identified hazardous substances.
    OSHA is interested in exploring task-based control approaches as a
technique for developing specification standards for the control of
hazardous substances in the workplace as an alternative or supplement
to PELs. Such an approach may offer the advantage of providing
employers with specific guidance on how to protect workers from
exposure and reduce or eliminate the need for conducting regular
exposure assessments to evaluate the effectiveness of exposure control
strategies. OSHA has developed specification-oriented health standards
in the past, in particular, those for lead and asbestos in
construction.
    More recently, OSHA developed a control-specification-based
approach for controlling exposures to crystalline silica dust in
construction operations (OSHA, 2009; Ex. #136, OSHA, 2013b; Ex. #137).
Construction operations are particularly amenable to specification
standards due to the task-based nature of the work. The National
Institute for Occupational Safety and Health (NIOSH), the Center to
Protect Workers' Rights--a research arm of the Building and
Construction Trades Department, AFL-CIO--has developed and used a
"Task-Based Exposure Assessment Model (T-BEAM)" for construction. The
characteristic elements of T-BEAM are: (1) an emphasis on the
identification, implementation, and evaluation of engineering and work
practice controls; and (2) use of experienced, specially trained
construction workers (construction safety and health specialists) in
the exposure assessment process. A task-based approach was used because
tasks, or specialized skills, form the single greatest thread of
continuity in the dynamic environment of construction (Susi et al.,
2000; Ex. #138).
    A new American National Standards Institute Standard (ANSI A10.49)
based on GHS health hazard categories and utilizing a task-based
approach is also being developed to address chemical hazards in
construction (ASSE, 2012; Ex. #139). The standard requires employers to
first identify tasks involving the use of chemicals and create a hazard
communication inventory for these tasks. Then the employer must
determine the hazard level and exposure level, and finally develop a
control plan based on the hazard and exposure classifications. If the
chemicals used in the task are low hazard and the task is low exposure,
then the control plan requires following the SDS and label precautions.
If, however, the task involves greater than minimal hazard or exposure,
a more protective control plan must be developed.
    However, developing specification standards governing exposure to
health standards for general industry operations presents a different
challenge. Given the diversity in the nature of industrial operations
across a range of industry sectors that might be affected by a chemical
standard, OSHA is concerned that it will be more difficult to develop
specification standards for exposure controls that are specific enough
to clearly delineate obligations of employers to protect employees, and
yet are general enough to provide employers flexibility to implement
controls that are suitable for their workplaces and that allow for
future innovation in control technologies.
    Question V.B.15: OSHA requests comment on whether and how task-
based exposure control approaches might be effectively used as a
regulatory strategy for health standards.

VI. Authority and Signature

    David Michaels, Ph.D., MPH, Assistant Secretary of Labor for
Occupational Safety and Health, U.S. Department of Labor, 200
Constitution Avenue NW., Washington, DC 20210, directed the preparation
of this notice. OSHA is issuing this notice under 29 U.S.C. 653, 655,
657; 33 U.S.C. 941; 40 U.S.C. 3704 et seq.; Secretary of Labor's Order
1-2012 (77 FR 3912, 1/25/2012); and 29 CFR Part 1911.

    Signed at Washington, DC, on September 30, 2014.
David Michaels,
Assistant Secretary of Labor for Occupational Safety and Health.

Appendix A: History, Legal Background, and Significant Court Decisions

I. Background

    Since the OSH Act was enacted in 1970, OSHA has made significant
achievements toward improving the health and safety of America's
workers. The OSH Act gave "every working man and woman in the
Nation" for the first time, a legal right to "safe and healthful
working conditions." OSH Act Sec.  2(a); 29 U.S.C. 651. (Ex. #9)
Congress recognized that "the problem of assuring safe and
healthful workplaces for our men and women ranks in importance with
any that engages the national attention today." S. Rep. 91-1282 at
2 (1970; Ex. #17). Indeed, when establishing the OSH Act, Congress
was concerned about protecting workers from known hazards as well as
from the numerous new hazards entering the workplace:

    Occupational diseases which first commanded attention at the
beginning of the industrial revolution are still undermining the
health of workers. . . . Workers in dusty trades still contract
various respiratory diseases. Other materials long in industrial use
are only now being discovered to have toxic effects. In addition,
technological advances and new processes in American industry have
brought numerous new hazards to the workplace. S. Rep. 91-1282 at 2.

    Many of the occupational diseases first discovered during the
industrial revolution, and which later spurred Congress to create
OSHA, still pose a significant harm to U.S. workers. While the
number of hazardous chemicals to which workers are exposed has
increased exponentially due to new formulations of chemical
mixtures, OSHA has not been successful in establishing standards
that adequately protect workers from hazardous chemical exposures,
even from the older, more familiar chemicals.
    OSHA's PELs are mandatory limits for air contaminants above
which workers must not be exposed. OSHA PELs generally refer to
differing amounts of time during which the worker can be exposed:
(1) Time weighted averages (TWAs) which establish average limits for
eight-hour exposures; (2) short-term limits (STELs) which establish
limits for short term exposures; and (3) ceiling limits, which set
never-to-be exceeded maximum exposure levels.
    OSHA's PELs have existed nearly as long as the agency itself.
Most of OSHA's current PELs were adopted by the agency in 1971. OSHA
currently has PELs for approximately 470 hazardous substances, which
are included in the Z-Tables in general industry at 29 CFR part
1910.1000 (Ex. #4) and in three maritime subsectors: Part 1915.1000
(Shipyard Employment; Ex. #5); part 1917 (Marine Terminals; Ex.
#140); and part 1918 (Longshoring; Ex. #141). Z-Tables that apply in
construction are found at part 1926.55 (Ex. #6). There are
inconsistencies in the PELs that apply across industry sectors which
resulted from the regulatory history of each divergent industry
sector.
    As discussed in further detail below, the Agency attempted to
update the general industry PELs in 1989, but that revision was
vacated by judicial decision in 1992. As such, the 1971 PELs remain
the exposure limits with which most U.S. workplaces are required to
comply. The Agency also promulgates "comprehensive" substance-
specific standards (e.g., lead, methylene chloride) which, in
addition to PELs, require additional ancillary provisions such as
housekeeping, exposure monitoring, and medical surveillance.

II. OSHA's Statutory Authority, Adoption of the PELs in 1971, and the
1989 Attempted Revision

A. The Purpose of the OSH Act and OSHA's Authority To Regulate
Hazardous Chemicals

    The OSH Act vests the Secretary of Labor with the power to
"promulgate, modify, or revoke" mandatory occupational safety and
health standards. OSH Act section 6(b), 29 U.S.C. 655(b). An
"occupational safety and health standard," as defined by section
3(8) of the OSH Act, 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 and places of employment." OSH
Act section 3(8), 29 U.S.C. 652(8). (Ex. #9)
    The OSH Act provides three separate approaches for promulgating
standards. The first approach, in section 6(a) of the OSH Act,
provided OSHA with an initial two-year window in which to adopt
standards without hearing or public comment. Additionally, sections
6(b) and 6(c) provide methods currently available to the agency for
promulgating health standards. Section 6(b) allows OSHA to create
and update standards through notice and comment rulemaking, and
section 6(c) provides OSHA with the authority to set emergency
temporary standards. OSHA has not successfully adopted an emergency
temporary standard for over thirty years, and it is not discussed
further here.

B. The Adoption of the PELs Under Section 6(a)

    Under section 6(a), OSHA was permitted to adopt "any national
consensus standard and any established Federal standard" so long as
the standard "improved safety or health for specifically designated
employees." 29 U.S.C. 655(a). The purpose of providing OSHA with
this two-year window "was to establish as rapidly as possible
national occupational safety and health standards with which
industry is familiar." S. Rep. 91-1282 at 6. When establishing this
fast track to rulemaking, Congress emphasized the temporary nature
of the approach, noting that these "standards may not be as
effective or up to date as is desirable, but they will be useful for
immediately providing a nationwide minimum level of health and
safety." S. Rep. 91-1282 at 6. (Ex. #17)
    Establishing PELs was one of the first actions taken by OSHA.
Most of the PELs contained in the Tables Z-1, Z-2, and Z-3 of 29 CFR
1910.1000 (Ex. #4) for general industry, as well as those in
construction and maritime were adopted during the initial two-year
window under section 6(a). OSHA adopted approximately 400
occupational exposure limits for general industry that were based on
the American Conference of Governmental Industrial Hygienist's
(ACGIH) 1968 list of Threshold Value Limits (TLVs). In addition,
about 25 additional exposure limits recommended by the American
Standards Association (presently called the American National
Standards Institute) (ANSI), were adopted as national consensus
standards. 36 FR 10466 (Ex. #142). Currently the exposure limits
that apply to construction were derived from the 1970 ACGIH TLVs and
certain substance specific Sec. 6(b) standards.
    The industry sector that is referred to today as "Maritime"
has a long and somewhat confusing history. The Department of Labor
has had some authority since 1958 for the maritime industry under
the Longshore and Harbor Workers Compensation Act (33 U.S.C. 901 et
seq.). Specifically authority was granted under Public Law 89-742
for the Secretary of Labor to issue regulations to protect the
health and safety of longshoremen, marine terminal workers, ship
repairers, shipbuilders, and ship breakers. Under Section 4(b)(2) of
the OSH Act, 33 U.S.C. 941 (Ex. #143) became OSHA standards in 1971.
    At that time, the Shipyard standards were in three parts of 29
CFR; part 1915 for ship repairing, part 1916 for shipbuilding and
part 1917 for shipbreaking. In 1982 parts 1915, 1916 and 1917 were
consolidated into a new part 1915, Shipyards. As a consequence of
their history, the PELs applicable to the new part 1915, Shipyards,
are complex. Depending upon the specific operation, either the 1970
TLVs or 1971 PELS (originally 1968 TLVs) apply. See Sec. Sec.
1915.11, 1915.12, 1915.32 and 1915.33 (Ex. #144). Additionally,
several of the OSHA single-substance standards apply.
    Pursuant to the Longshoremen and Harbor Worker Compensation Acts
of 1958 amendments, in 1960 OSHA issued regulations protecting
longshore employees, along with marine terminal employees. These
regulations were adopted as OSHA standards and later recodified. In
1983, OSHA issued a final standard specifically covering marine
terminals (29 CFR part 1917) separately from longshoring. The Marine
Terminal Standard basically requires that no employee be exposed to
air contaminants over the limits set in the 1971 Z-Tables. See
Sec. Sec.  1917.2, 1917.22, 23, 25. (Ex. #140)
    Longshoring operations continue to be regulated by 29 CFR Part
1918 (Ex. #141). OSHA has consistently interpreted that the air
contaminant exposure limits set forth in 1910.1000 (Ex. #4) are
applicable pursuant to 1910.5(c) to longshoring because no
quantitative exposure limits are set forth for air contaminants,
other than carbon monoxide.
    As discussed above, the Agency was given authority to adopt
standards to provide initial protections for workers from what the
Congress deemed to be the most dangerous workplace threats. Congress
felt that it was "essential that such standards be constantly
improved and replaced as new knowledge and techniques are
developed." S. Rep. 91-1282 at 6. (Ex. #17) However, because OSHA
has been unable to update the PELs, they remain frozen at the levels
at which they were initially adopted. OSHA's PELs are largely based
on acute health effects and do not take into consideration newer
research regarding chronic effects occurring at lower occupational
exposures. Thus, although there have been radical changes in our
understanding of airborne contaminants, updates in technology, and
changes to industry practices, OSHA's PELs are still based on
research performed during the 1950s and 1960s. In contrast, the
ACGIH annually reviews chemical substances and updates its list of
TLVs[supreg]. Where OSHA currently has PELs for approximately 470
chemical hazards, the ACGIH recommends TLVs[supreg] for more than
700 chemical substances and physical agents, approximately 200 of
which have been updated since 1971. (FACOSH, 2012; Ex. #145).

C. Section 6(b) Notice and Comment Rulemaking

    Section 6(b) of the OSH Act provides OSHA with the authority to
promulgate health standards. OSHA promulgates two main types of
health standards: (i) PELs, and (ii) comprehensive standards, which,
as the name implies, consist of provisions to protect workers in
addition to PELs. Section 6(b)(5) imposes specific requirements
governing the adoption of health standards:

    [T]he 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(6)(b)(5). (Ex. #9)
    The courts have elaborated on the findings OSHA must make before
adopting a 6(b)(5) standard. One such case, Industrial Union Dept.,
AFL-CIO v. American Petroleum Institute, 448 U.S. 607 (1980) (the
Benzene case; Ex. #10), has had a major impact on OSHA rulemaking by
establishing a threshold requirement that before the agency can
promulgate a health standard it must show that a significant risk of
material impairment exists, which can be eliminated or lessened by a
change in practices. Additionally, the phrase "to the extent
feasible" in section 6(b)(5) has been interpreted by the courts to
require that OSHA show that a standard is both economically and
technologically feasible. American Textile v. Donovan, 452 U.S. 490
(1981) (the Cotton Dust case; Ex. #15); United Steelworkers v.
Marshall, 647 F.2d 1189, 1264 (D.C. Cir. 1980) (the Lead I case; Ex.
#12). These cases will be discussed in greater detail in Section III
of this Appendix.

D. 1989 Air Contaminants Standard

    In 1989, OSHA published the Air Contaminants final rule, which
remains the Agency's most significant attempt at updating the PELs.
Unlike typical substance-specific rulemakings, where OSHA develops a
comprehensive standard, the Air Contaminants final rule was only
intended to update existing PELs and to add new PELs for substances
not currently regulated. As such, the final rule did not include
ancillary provisions (e.g. exposure monitoring, medical surveillance,
requirements for personal protective equipment, or labeling) because
OSHA determined that these provisions would delay and unnecessarily
complicate the PELs update.
Appendix B. to this Request for Information contains the table of
PELs from the 1989 Air Contaminants Final Rule. The table includes
both PELs originally adopted by OSHA in 1971 and the PELs
established under the 1989 final rule.
    In order to determine a starting point for updating the general
industry PELs for chemicals on Tables Z-1, Z-2, and Z-3 of 29 CFR
1910.1000 (Ex. #4), and for creating new PELs for some substances
not listed in those tables, OSHA analyzed existing databases and
lists of occupational exposure limits (OELs) to determine the scope
of the rulemaking. After extensive review of all available sources
of OELs, including the National Institute for Occupational Safety
and Health (NIOSH) Recommended Exposure Levels (RELs), the American
Conference of Industrial Hygienists (ACGIH) Threshold Limit Values
(TLVs[supreg]), the American Industrial Hygiene Association (AIHA)
Workplace Environmental Exposure Levels (WEELs), and limits from
other countries, OSHA ultimately selected the ACGIH's 1987-88 TLVs
to identify the basis for which substances and corresponding
exposure values that would be included in the proposed rule. 53 FR
20977. The TLVs were selected as a reference point because of the
number of substances they covered, the availability of written
documentation on how the TLVs were selected, and the general
acceptance of the TLVs by industrial hygienists, other occupational
health professionals, and industry. (53 FR 20967; Ex. #18, 54 FR
2375; Ex. #7)
    After determining the scope of hazardous chemicals to be
included in the rulemaking, OSHA began the process of identifying
the most appropriate new PELs to be proposed. OSHA considered both
the ACGIH TLVs and the NIOSH RELs as a starting point. (53 FR 20966-
67; Ex. #18) When the TLV and REL were similar, OSHA reviewed both
the ACGIH documentation and the NIOSH recommendation. Where the TLV
and REL "differed significantly," OSHA reviewed the studies and
reasoning upon which the NIOSH and ACGIH recommendations were based
to determine which was more appropriate. OSHA presumed that a
significant difference did not exist between the TLV and the REL for
a chemical when:
    (a) The TLV and REL values are the same;
    (b) TLV and REL values differ by less than 10 percent;
    (c) The TLV and REL Time Weighted Averages (TWA) are the same,
but there are differences in the Short Term Exposure Limit (STEL) or
Ceiling (C); or
    (d) The TWA in one data base is the same, or one-half, the STEL/
C in the other data base. 53 FR 20977.
    In reviewing the evidence, OSHA first determined whether the
studies and analyses were valid and of reasonable scientific
quality. Second, it determined, based on the studies, if the
published documentation of the REL or TLV would meet OSHA's legal
requirements for setting a PEL. Thus, OSHA reviewed the evidence of
significant risk at the existing PEL or, if there was no PEL, at
exposures which might exist in the workplace in the absence of any
limit. Third, OSHA reviewed the studies to determine if the new PEL
would lead to substantial reduction in significant risk. 54 FR 2372.
    OSHA's determination of where the new PEL should be set was
based on its review and analysis of the information found in these
sources. OSHA set the new PELs based on a review of the available
evidence. 54 FR 2402. Safety factors were applied on a case-by-case
basis. (54 FR 2365, 2399; Ex. #7). Based on the analysis discussed
above, OSHA summarized the health evidence for each individual
substance and determined when and at what level a new limit was
necessary to substantially reduce a significant risk of material
impairment of health or functional capacity among American workers.
The following example illustrates the type of analysis that OSHA
conducted for each substance:

    OSHA had no former limit for potassium hydroxide. A ceiling
limit of 2 mg/m(3) was proposed by the Agency based on the ACGIH
recommendation, and NIOSH (Ex. 8-47, Table N1) concurred with this
proposal. OSHA has concluded that this limit is necessary to afford
workers protection from irritant effects and is establishing the 2-
mg/m(3) ceiling limit for potassium hydroxide in the final rule.

    [One commenter] (Ex. 3-830) commented that there was no basis
for establishing an occupational limit for potassium hydroxide. OSHA
disagrees and notes that the irritant effects of potassium hydroxide
dusts, mists, and aerosols have been documented (ACGIH 1986/Ex. 1-3,
p. 495; Karpov 1971/Ex. 1-1115). Although dose-response data are
lacking for this substance, it is reasonable to expect potassium
hydroxide to exhibit irritant properties similar to those of sodium
hydroxide, a structurally related strong alkali. In its criteria
document, NIOSH (1976k/Ex. 1-965) cites a personal communication
(Lewis 1974), which reported that short-term exposures (2 to 15
minutes) to 2 mg/m(3) sodium hydroxide caused "noticeable" but not
excessive upper respiratory tract irritation. Therefore, OSHA finds
that the 2-mg/m(3) ceiling limit will provide workers with an
environment that minimizes respiratory tract irritation, which the
Agency considers to be material impairment of health. To reduce
these risks, OSHA is establishing a ceiling limit of 2 mg/m(3) for
potassium hydroxide. (54 FR 2332 et seq.)

    OSHA proposed making 212 PELs more protective and setting new
PELs for 164 substances not previously regulated by OSHA. Substances
for which the PEL was already aligned with a newer TLV were not
included.
    In order to determine whether the Air Contaminants rule was
feasible, OSHA prepared the regulatory impact analysis in two
phases. The first phase of its feasibility analyses involved using
secondary databases to collect information on the chemicals to be
regulated and the industries in which they were used. These
databases provided information on the toxicity and health effects of
exposure to chemicals covered by the rulemaking, on engineering
controls, and on emergency response procedures. (54 FR 2725; Ex.
#7).
    Two primary databases were used to collect information on the
nature and extent of employee exposures to the substances covered by
the rule. One database was the 1982 NIOSH National Occupational
Exposure Survey (NOES), which collected information from 4,500
businesses on the number of workers exposed to hazardous substances.
The second database was OSHA's Integrated Management Information
System (IMIS) which contains air samples taken since 1979 by OSHA
industrial hygienists during compliance inspections. OSHA also
consulted industrial hygienists and engineers who provided
information about the exposure controls in use, the number and size
of plants that would be impacted by the rulemaking, and the
estimated costs associated with meeting the new PELs. (54 FR 2373,
2725, 2736; Ex. #7).
    As part of the second phase of its feasibility analyses, OSHA
performed an industry survey and site visits. The survey was the
largest survey ever conducted by OSHA and included responses from
5,700 firms in industries believed to use chemicals included in the
scope of the Air Contaminants proposal. It was designed to focus on
industry sectors that potentially had the highest compliance costs,
identified through an analysis of existing exposure data at the
four-digit SIC (Standards Industrial Classification) code level. 54
FR 2843. The survey gathered data on chemicals, processes, exposures
and controls currently in use, which "permitted OSHA to refine the
Phase I preliminary estimates of technical and economic feasibility.
Site visits to 90 firms were conducted to verify the data collected
on chemicals, processes, controls, and employee exposures." 54 FR
2725; see also 54 FR 2736-39, 2768, 2843-69.
    OSHA analyzed the data collected in phases I and II to determine
whether the updated PELs were both technologically and economically
feasible for each industry sector covered. 54 FR 2374.
    For technological feasibility, OSHA evaluated engineering
controls and work practices available within industry sectors to
reduce employee exposures to the new PELs. In general, it found
three types of controls might be employed to reduce exposures:
Engineering controls, work practice and administrative controls, and
personal protective equipment. Engineering controls included local
exhaust ventilation, general ventilation, isolation of the worker
and enclosure of the source of the emission, and product
substitution. Work practice controls included housekeeping, material
handling procedures, leak detection, training, and personal hygiene.
Personal protective equipment included respirators, and where the
chemicals involved presented skin hazards, protective gloves and
clothing. 54 FR 2789-90, 2840.
    OSHA found that many processes required to reduce exposure were
"relatively standardized throughout industry and are used [to
control exposures] for a variety of substances." 54 FR 2373-74. It
"examined typical work processes found in a cross section of
industries" and had industry experts identify the major processes
that had the potential for hazardous exposures above the new PELs,
requiring new controls. For each affected industry group, OSHA
reviewed the data it had collected to "identify examples of
successful application of controls to these processes." 54 FR 2790.
Based on its review OSHA found that "engineering controls and
improved work practices [were] available to reduce exposure levels
in almost all circumstances." 54 FR 2727. In some cases, it found
respirators or other protective equipment was necessary. 54 FR 2727,
2813-15, 2840. For each relevant industry sector (which was at the
2, 3, or 4 digit SIC code level, depending on the processes
involved). As the court explained in Air Contaminants, 965 F.2d at
981 (Ex. #8):

    The SIC codes classify by type of activity for purposes of
promoting uniformity and comparability in the presentation of data.
As the codes go from two and three digits to four digits, the
groupings become progressively more specific. For example, SIC Code
28 represents "Chemicals and Allied Products," SIC Code 281
represents "Industrial Inorganic Chemicals," and SIC Code 2812
includes only "Alkalies and Chlorine."

    OSHA prepared a list of the processes identified and the
engineering controls and personal protective equipment (PPE)
required to reach the new PELs. 54 FR 2814-39. In almost all cases,
the OSHA list showed that the new PELs could be reached through a
combination of ventilation and enclosure controls. 54 FR 2816-39.
OSHA received and addressed numerous comments on the controls it
proposed for use in various industries. 54 FR 2790-2813. OSHA found
that "in the overwhelming majority of situations where air
contaminants [were] encountered by workers, compliance [could] be
achieved by applying known engineering control methods, and work
practice improvements." 54 FR 2789.
    To assess economic feasibility, OSHA "made estimates of the
costs to reduce exposure based on the scale of operations, type of
process, and degree of exposure reduction needed" based primarily
on the results of the survey. 54 FR 2373, 2841-51. For each survey
respondent, OSHA identified the processes employed at the plant and
made a determination about whether workers would be exposed to a
chemical in excess of a new PEL. 54 FR 2843-47. For those processes
where the new PEL would be exceeded, OSHA estimated the cost of
controls necessary to meet the PEL. 54 FR 2947-51. Process control
costs were then summed by establishment and costs "for the survey
establishment were then weighted (by SIC and size) to represent
compliance costs for the universe of affected plants." 54 FR 2851.
OSHA received and addressed many comments on its cost approach and
assumptions. (54 FR 2854-62; Ex. #7).
    Based on the survey, OSHA determined that 74 percent of
establishments with hazardous chemicals had no exposures in excess
of the new PELs and would incur no costs, 22 percent would incur
costs to implement additional engineering controls, and 4 percent
would be required to provide personal protective equipment only for
maintenance workers. 54 FR 2851. OSHA estimated the total compliance
cost to be $788 million per year annualized over ten years at a ten
percent discount rate. 54 FR 2851. OSHA assessed the economic impact
of the standard on industry profits on the two-digit SIC level.
Assuming industry would not be able to pass the additional costs on
to customers, the average change in profits was less than one
percent, with the largest change in SIC 30 (Rubber and Plastics) of
2.3 percent. 54 FR 2885, 2887. Alternatively, assuming that industry
could pass on all costs associated with the rule to its customers,
OSHA determined that for no industry sector would prices increase on
average more than half of a percent. 54 FR 2886, 2887. In neither
case was the economic impact significant, OSHA found, and the new
standard was therefore considered by the Agency to be economically
feasible. (54 FR 2733, 2887; Ex. #7)
    The Air Contaminants final rule was published on January 19,
1989. In the final rule, OSHA summarized the health evidence for
each individual substance, discussed over 2,000 studies, reviewed
and addressed all major comments submitted to the record, and
provided a rationale for each new PEL chosen. The final rule
differed from the proposal in a number of ways as OSHA changed many
of its preliminary assessments presented in the proposal based on
comments submitted to the record.
    Ultimately, the final rule adopted more protective PELs for 212
previously regulated substances, set new PELs for 164 previously
unregulated substances, and left unchanged an additional 52
substances, for which lower PELs were initially proposed. OSHA
estimated over 21 million employees were potentially exposed to
hazardous substances in the workplace and over 4.5 million employees
were currently exposed to levels above the old PELs or in the
absence of a PEL. OSHA projected the final rule would result in
potential reduction of over 55,000 lost workdays due to illnesses
per year and annual compliance with this final rule would prevent an
average of 683 fatalities annually from exposures to hazardous
substances. 54 FR 2725.
    The update to the Air Contaminants standard generally received
wide support from both industry and labor. However, there was
dissatisfaction on the part of some industry representatives and
union leaders, who brought petitions for review challenging the
standard. For example, some industry petitioners argued that OSHA's
use of generic findings, the inclusion of so many substances in one
rulemaking, and the allegedly insufficient time provided for comment
by interested parties created a record inadequate to support the new
set of PELs. In contrast, the unions challenged the generic approach
used by OSHA to promulgate the standard and argued that several PELs
were not protective enough. The unions also asserted that OSHA's
failure to include any ancillary provisions, such as exposure
monitoring and medical surveillance, prevented employers from
ensuring the exposure limits were not exceeded and resulted in less-
protective PELs.
    Fifteen of the twenty-five lawsuits were settled; of the
remaining suits, nine were from industry groups challenging seven
specific exposure limits, and one was from the unions challenging 16
substances. Pursuant to 28 U.S.C. 2112(a), all petitions for review
were consolidated for disposition and transferred to the Eleventh
Circuit Court of Appeals. AFL-CIO v. OSHA, 965, F.2d 962, 981-82
(11th Cir. 1992) (Air Contaminants). Although only 23 of the new
PELs were challenged, the court ultimately decided to vacate the
entire rulemaking, finding that "OSHA [had] not sufficiently
explained or supported its threshold determination that exposure to
these substances at previous levels posed a significant risk of
these material health impairments or that the new standard
eliminates or reduces that risk to the extent feasible." Air
Contaminants, 965 F.2d at 986-987; Ex. #8.
    After publishing the Air Contaminants Final Rule for general
industry, OSHA proposed amending the PELs for the maritime and
construction industry sectors and establishing PELs to cover the
agriculture industry sector. OSHA published a Notice of Proposed
Rulemaking (NPRM) on June 12, 1992, which included more protective
exposure limits for approximately 210 substances currently regulated
in the construction and maritime industries and added new exposure
limits for approximately 160 chemicals to protect these workers. (57
FR 26002; Ex. #146). The notice also proposed approximately 220 PELs
to cover the agriculture industry. OSHA extended the comment period
indefinitely while it considered possible responses to the Air
Contaminants court decision. Once it became clear that an appeal
would not be pursued, the Agency halted work on the project.

III. Significant Court Decisions Shaping OSHA's Rulemaking Process and
OSHA's Approach to Updating Its Permissible Exposure Limits

    OSHA's Air Contaminants final rule is the agency's most
significant attempt to move away from developing individual,
substance-specific standards. As discussed above in Section II, this
rule attempted to establish or revise 376 exposure limits for
chemicals in a single rulemaking. OSHA's efforts in reducing
occupational illnesses and the mortality associated with hazardous
chemical exposure has largely been through developing substance
specific standards, such as Hexavalent Chromium general industry (29
CFR 1910.1026; Ex. #26), shipyards (29 CFR 1915.1026), and
construction (29 CFR 1926.1026) and Methylene Chloride (29 CFR
1910.1052; Ex. #27). These standards, in addition to setting PELs,
establish other provisions to help reduce risk to workers, such as
requirements to monitor exposure, train workers and conduct medical
surveillance, if appropriate.
However, due to the associated time and costs, promulgating
comprehensive rules for individual chemical hazards is an
ineffective approach to address all chemical hazard exposures
because of the sheer number of chemicals and mixtures to which
workers are exposed on a daily basis. To date, only 30 comprehensive
individual standards have been successfully published by the Agency
to address hazardous chemicals in the workplace.
    The courts have had a significant impact on OSHA's rulemaking
process by articulating specific burdens OSHA must meet before
promulgating a standard. It was because the Air Contaminants court
found that OSHA had failed to meet some of these burdens that the
court vacated OSHA's attempt to update the PELs. This section
discusses the important cases laying out OSHA's burdens under the
OSH Act, and summarizes the reasons the Air Contaminants court gave
for finding that OSHA had not satisfied those burdens. These cases
influence what steps OSHA may take in the future to update the PELs.

A. The Substantial Evidence Test: OSHA's Burden of Proof for
Promulgating Health Standards

    The test used by the courts to determine whether OSHA has
reached its burden of proof is the "substantial evidence test."
This test, which applies to policy decisions as well as factual
determinations, is set forth in section 6(f) of the OSH Act, which
states: "the determinations of the Secretary shall be conclusive if
supported by substantial evidence in the record considered as a
whole." 29 U.S.C. 655(f). "Substantial evidence" has been defined
as "such relevant evidence as a reasonable mind might accept as
adequate to support a conclusion." Cotton Dust, 452 U.S. at 522;
Ex. #15 (quoting Universal Camera Corp. v. NLRB, 340 U.S. 474, 477
(1951) Ex. #16).
    Although the substantial evidence test requires OSHA to show
that the record as a whole supports the final rule, OSHA is not
required to wait for "scientific certainty" before promulgating a
health standard. Benzene, 448 U.S. at 656 (Ex. #10). Rather, to meet
its burden of proof under the "substantial evidence test," the
agency need only "identify relevant factual evidence, to explain
the logic and the policies underlying any legislative choice, to
state candidly any assumptions on which it relies, and to present
its reasons for rejecting significant contrary evidence and
argument." Lead I, 647 F.2d. at 1207; Ex. #12.

B. The Air Contaminants Case

    OSHA published the Air Contaminants final rule on January 19,
1989. As discussed in Section II, the standard adopted more
protective PELs for 212 previously regulated substances, set new
PELs for 164 previously unregulated substances, left unchanged the
PELs for 52 substances for which lower limits had been proposed, and
raised the PEL for one substance. 54 FR 2332. The rule was
challenged by both industry and labor groups, which both raised a
series of issues regarding the validity of the final rule.
    The first issue addressed by the court was whether OSHA's
"generic" approach to rulemaking used to update or create new PELs
for 376 chemicals in a single rulemaking was permissible under the
OSH Act. Although the Eleventh Circuit determined that the Air
Contaminants final rule did not fit within the classic definition of
a generic rulemaking, the court upheld the format used by OSHA to
update the PELs. Air Contaminants, 965 F.2d at 972. The court, in so
holding, reasoned "nothing in the OSH Act prevented OSHA from
addressing multiple substances in a single rulemaking." Air
Contaminants, 965 F.2d at 972. The court also upheld OSHA's
statutory authority to select the substances and determine the
parameters of its rules. However, the court stated that even though
OSHA was permitted to promulgate multi-substance rules, each
substance was required to "stand independently, i.e., . . . each
PEL must be supported by substantial evidence in the record
considered as a whole and accompanied by adequate explanation." Air
Contaminants, 965 F.2d at 972; Ex. #8.

C. Significant Risk of a Material Impairment

1. The Benzene Case and Significant Risk

    The significant risk requirement was first articulated in 1980
in a plurality decision of the Supreme Court in Benzene, 448 U.S.
607. The petitioners in Benzene challenged OSHA's rule lowering its
PEL for benzene from 10 ppm to 1 ppm. In support of the new PEL,
OSHA found that benzene caused leukemia and that the evidence did
not show that there was a safe threshold exposure level below which
no excess leukemia would occur. Applying its policy to treat
carcinogens as posing a risk at any level of exposure where such a
threshold could not be established, OSHA chose the new PEL of 1 ppm
based on its finding that it was the lowest feasible exposure level.
This was because Section 6(b)(5) of the OSH Act requires standards
to be set at the most protective level that is feasible. See
Benzene, 448 U.S. at 633-37; Ex. #10.
    The Benzene Court rejected OSHA's approach. First, it found that
the OSH Act did not require employers to "eliminate all risks of
harm from their workplaces." The OSH Act defines "occupational
safety and health standard" to be standard that require the
adoption of practices which are "reasonably necessary or
appropriate to provide safe or healthful employment and places of
employment". OSH Act Sec.  3(8), 29 U.S.C. 652(8); Ex. #9.
    Relying on this definition, the Court found that the Act only
required that employers ensure that their workplaces are safe, that
is, that their workers are not exposed to "significant risk[s] of
harm." 448 U.S. at 642. Second, the Court made clear that it is
OSHA's burden to establish that a significant risk is present at the
current standard before lowering a PEL. The burden of proof is
normally on the proponent, the Court noted, and there was no
indication in the OSH Act that Congress intended to change this
rule. 448 U.S. at 653, 655. Thus, the Court held that, before
promulgating a health standard, OSHA is required to make a
"threshold finding that a place of employment is unsafe-in the
sense that significant risks are present and can be eliminated or
lessened by a change in practices" before it can adopt a new
standard. Benzene, 448 U.S. at 642; Ex. #10.
    Although the Court declined to establish a set test for
determining whether a workplace is unsafe, it did provide guidance
on what constitutes a significant risk. The Court stated a
significant risk was one that a reasonable person would consider
significant and "take appropriate steps to decrease or eliminate."
Benzene, 448 U.S. at 655 (Ex. #10). For example, it said, a one in a
1,000 risk would satisfy the requirement. However, this example was
merely an illustration, not a hard line rule. The Court made it
clear that determining whether a risk was "significant" was not a
"mathematical straitjacket" and did not require the Agency to
calculate the exact probability of harm. 448 U.S. at 655. OSHA was
not required to support a significant risk finding "with anything
approaching scientific certainty" and was free to use
"conservative assumptions" in interpreting the evidence. 448 U.S.
at 656. Still, because OSHA had not made a significant risk finding
at the 10 ppm level (indeed, the Court characterized the evidence of
leukemia in the record at the 10 ppm level as "sketch[y]"), the
Court vacated the new PEL and remanded the matter to OSHA.

2. OSHA's Post-Benzene Approach to Significant Risk and Air
Contaminants

    In past rulemakings involving hazardous chemicals, OSHA
satisfied its requirement to show that a significant risk of harm is
present by estimating the risk to workers subject to a lifetime of
exposure at various possible exposure levels. These estimates have
typically been based on quantitative risk assessments. As a general
policy, OSHA has considered a lifetime excess risk of one death or
serious illness per 1000 workers associated with occupational
exposure over a 45 year working life as clearly representing a
significant risk. However, as noted above, Benzene does not require
OSHA to use such a rigid or formulaic criterion. Nevertheless, OSHA
has taken a conservative approach and has used the 1:1,000 example
as a useful benchmark for determining significant risk. This
approach has often involved the use of the quantitative risk
assessment models OSHA has employed in developing substance-specific
health standards.
    In the Air Contaminants rule, OSHA departed from this approach.
Rather, as noted above, it looked at whether studies showed excess
effects of concern at concentrations lower than allowed under OSHA's
existing standard. Where they did, OSHA made a significant risk
finding and either set a PEL (where none existed previously) or
lowered the existing PEL. These new PELs were based on agency
judgment, taking into account the existing studies, and as
appropriate, safety factors. Both industry and union petitioners
challenged aspects of OSHA's approach to making its significant risk
determinations. The AFL-CIO argued that OSHA's rule was
"systematically under protective," and asserted that 16 of the
exposure limits in the final rule were too high. For example, the
AFL-CIO argued that OSHA had made a policy determination not to
lower the PELs for carbon tetrachloride and vinyl bromide even
though the exposure limits chosen would continue to pose a residual
risk in excess of 3.7 deaths per 1,000 workers exposed over the course
of their working lifetime. The court agreed with the AFL-CIO, finding
that OSHA failed to provide adequate evidence to support the higher
PEL chosen by the agency.
The court found that some of the PELs chosen by the Agency were at
levels that would continue to pose a significant risk of material
health impairment, and concluded that OSHA's decision was due to
time and resource constraints, rather than legitimate
considerations, such as feasibility. Air Contaminants, 965 F.2d at
976-77; Ex. #8.
    Conversely, the American Iron and Steel Institute (AISI; Ex.
#147) argued that OSHA set the PELs for certain substances below the
level substantiated by the evidence. AISI argued that OSHA failed to
quantify the risk of material health impairment at present exposure
levels posed by individual substances and instead relied on
assumptions in order to select its updated PELs. The court agreed
with the AISI, finding that although OSHA summarized the studies on
health effects in the final rule, it did not explain why the
"studies mandated a particular PEL chosen." Air Contaminants, 965
F.2d at 976. Specifically, the court stated that OSHA failed to
quantify the risk from individual substances and merely provided
conclusory statements that the new PEL would reduce a significant
risk of material health effects. Air Contaminants, 965 F.2d at 975.
    OSHA argued to the court that it relied on safety factors in
setting PELs. Safety or uncertainty factors are used to ensure that
exposure limits for a hazardous substance are set sufficiently below
the levels at which adverse effects have been observed to assure
adequate protection for all exposed employees. As explained in the
1989 Air Contaminants rule, regulators use safety factors in this
context to account for statistical limitations in studies showing no
observed effects, the uncertainties in extrapolating effects
observed in animals to humans, and variation in human responses. The
size of the proper safety factor is a matter of professional
judgment. 54 FR 2397-98
    The Eleventh Circuit rejected OSHA's use of safety factors in
the Air Contaminants rule, however. While noting that the Benzene
case held that OSHA is permitted "to use conservative assumptions
in interpreting data . . ., risking error on the side of
overprotection rather than under protection," Benzene, 448 U.S. at
656, the Air Contaminants court found that OSHA had not adequately
supported the use of safety factors in this rule. The court observed
that "the difference between the level shown by the evidence and
the final PEL is sometimes substantial," and assumed that though
"it is not expressly stated, that for each of those substances OSHA
applied a safety factor to arrive at the final standard." 965 F.2d
at 978. OSHA had not indicated "how the existing evidence for
individual substances was inadequate to show the extent of risk for
these factors," and "failed to explain the method by which its
safety factors were determined." Air Contaminants, 965 F.2d at 978.
"OSHA may use assumptions but only to the extent that those
assumptions have some basis in reputable scientific evidence," the
court concluded. Air Contaminants, 965 F.2d at 978-979. See Section
IV. A. for additional discussion of the use of safety factors in
risk assessment.
    Ultimately, although the Eleventh Circuit noted that OSHA
"probably established that most or all of the substances involved
do pose a significant risk at some level," the court determined
that OSHA failed to adequately explain or provide evidence to
support its conclusion that "exposure to these substances at
previous levels posed a significant risk . . . or that the new
standard eliminates or reduces that risk to the extent feasible."
Air Contaminants, 965 F.2d at 987. Therefore, the court vacated the
rule and remanded it to the agency.

3. Material Impairment

    Under section 6(b)(5), OSHA must set standards to protect
employees against "material impairment of health or functional
capacity." This requirement was uncontroversial in Benzene, since
the effect on which OSHA regulated was leukemia. However, in Air
Contaminants, AISI argued that not all of the health effects
addressed by OSHA in the final rule were material health effects.
Specifically, AISI stated that the category of "sensory
irritation," which OSHA used as an endpoint to set PELs for 79
substances, failed to distinguish between "materially impairing
sensory irritation and the less serious sort." AISI brief at page
24. The court rejected AISI's argument. It accepted OSHA's
explanation that material impairments may be any health effect,
permanent or transitory, that seriously threatens the health or job
performance of an employee, and held that, "OSHA is not required to
state with scientific certainty or precision the exact point at
which each type of sensory or physical irritation becomes a material
impairment." Air Contaminants, 965 F.2d at 975. "Section 6(b)(5)
of the [OSH] Act charges OSHA with addressing all forms of 'material
impairment of health or functional capacity," and not exclusively
those causing 'death or serious physical harm' or 'grave danger'
from exposure to toxic substances, the court held. Air Contaminants,
965 F.2d at 975; Ex. #8.

D. Technological and Economic Feasibility

    Once OSHA makes its threshold finding that a significant risk is
present at the current PEL or in the absence of a PEL and can be
reduced or eliminated by a standard, the Agency considers
feasibility. First, the feasibility requirement that originated in
Section 6(b)(5) of the OSH Act requires that the standard be
"technologically feasible," which generally means an industry has
to be able to develop the technology necessary to comply with the
requirements in the standard. Lead I, 647 F.2d at 1264-65; Ex. #12.
    Second, the standard must be "economically feasible," meaning
that an industry as a whole must be able to absorb the impact of the
costs associated with compliance with the standard. Id. at 1265.
OSHA has historically made determinations on technological
feasibility and economic feasibility separately.

1. Technological Feasibility

    A standard is technologically feasible if "a typical firm will
be able to develop and install engineering and work practice
controls that can meet the PEL in most operations." Lead I, 647
F.2d at 1272. Standards are permitted to be "technology forcing,"
meaning that OSHA can require industries to "develop new
technology" or "impose a standard which only the most
technologically advanced plants in an industry have been able to
achieve, even if only in some of their operations some of the
time." Lead I, 647 F.2d at 1264; Ex. #12.
    Technological feasibility analysis generally focuses on
demonstrating that PELs can be achieved through engineering and work
practice controls. However, the concept of technological feasibility
applies to all aspects of the standard, including air monitoring,
housekeeping, and respiratory protection requirements. Some courts
have required OSHA to determine whether a standard is
technologically feasible on an industry-by-industry basis, Color
Pigments Manufacturers Assoc. v. OSHA, 16 F.3d 1157 (Ex. #13), 1162-
63 (11th Cir. 1994); Air Contaminants, 965 F.2d at 981-82 (Ex. #8),
while another court has upheld technological feasibility findings
based on the nature of an activity across many industries rather
than on a pure industry basis, Public Citizen Health Research Group
v. United States Department of Labor, 557 F.3d 165,178-79 (3d Cir.
2009; Ex. #14).
    Regardless, OSHA must show the existence of "technology that is
either already in use or has been conceived and is reasonably
capable of experimental refinement and distribution within the
standard's deadlines," Lead I, 647 F.2d 1272. Where the agency
presents "substantial evidence that companies acting vigorously and
in good faith can develop the technology," the agency is not bound
to the technological status quo, and "can require industry to meet
PELs never attained anywhere." Lead I, 647 F.2d 1265; Ex. #12.
    OSHA usually demonstrates the technological feasibility of a PEL
by finding establishments in which the PEL is already being met and
identifying the controls in use, or by arguing that even if the PEL
is not currently being met in a given operation, the PEL could be
met with specific additional controls. OSHA is also concerned with
determining whether the conditions under which the PEL can be met in
specific plants are generalizable to an industry as whole. This
approach is very resource-intensive, as it commonly requires
gathering detailed information on exposure levels and controls for
each affected operation and process in an industry. OSHA's
inspection databases usually do not record this information, and
consequently OSHA makes site visits for the specific purpose of
determining technological feasibility. (See Section IV. of this
Request for Information for a detailed discussion of how OSHA
determines technological feasibility and possible alternatives to
current methods.)
    As noted above, in the Air Contaminants rule, OSHA made its
feasibility determination by gathering information on work processes
that might expose workers above the new PELs, and identifying controls
that had been successfully implemented to reduce the exposure to the
new limits.
It made these findings mainly at the two-digit SIC level, but also
at the three- and four-digit level where appropriate given the
processes involved. The Air Contaminants court rejected this
approach, finding that OSHA failed to make industry-specific
findings or identify the specific technologies capable of meeting
the proposed limit in industry-specific operations. Air
Contaminants, 965 F.2d at 981. While OSHA had identified primary air
contaminant control methods: engineering controls, administrative
controls and work practices and personal protective equipment, the
agency, "only provided a general description of how the generic
engineering controls might be used in the given sector." Air
Contaminants, 965 F.2d at 981. Though noting that OSHA need only
provide evidence sufficient to justify a "general presumption of
feasibility," the court held that this "does not grant OSHA
license to make overbroad generalities as to feasibility or to group
large categories of industries together without some explanation of
why findings for the group adequately represents the different
industries in that group." Air Contaminants, 965 F.2d at 981-82.
Accordingly, the court held that OSHA failed to establish the
technological feasibility of the new PELs in its final rule. Air
Contaminants, 965 F.2d at 982. As noted below, in a subsequent
rulemaking the reviewing court accepted OSHA's approach of grouping
numbers of industries.

2. Economic Feasibility

    With respect to economic feasibility, the courts have stated "A
standard is feasible if it does not threaten "massive dislocation"
to . . . or imperil the existence of the industry." United
Steelworkers v. Marshall, 647 F.2d 1189, 1265 (D.C. Cir. 1980) Lead
I,). In order to show this, the same court suggested, OSHA should
"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."
The same court noted, "[T]he court probably cannot expect hard and
precise estimates of costs. Nevertheless, the agency must of course
provide a reasonable assessment of the likely range of costs of its
standard, and the likely effects of those costs on the industry."
Lead I, 647 F.2d at 1265; Ex. #12.
    Economic feasibility does not entail a cost-benefit analysis of
the level of protection provided by the standard. As the Supreme
Court noted, Congress considered the costs of creating a safe and
healthful workplace to be the cost of doing business. Cotton Dust,
452 U.S. at 514, 520; Ex. #15. Instead, standards are economically
feasible if the standard will not substantially alter the industry's
competitive structure. Forging Indus. Ass'n v. Secretary of Labor,
773 F.2d 1436, 1453 (4th Cir. 1985; Ex. #148). In order to make a
determination of economic feasibility, OSHA should "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," Lead I, 647 F.2d at 1272,
noting that such analyses will not provide absolute certainty:

    [T]he court probably cannot expect hard and precise estimates of
costs. Nevertheless, the agency must of course provide a reasonable
assessment of the likely range of costs of its standard, and the
likely effects of those costs on the industry . . . . And OSHA can
revise any gloomy forecast that estimated costs will imperil an
industry by allowing for the industry's demonstrated ability to pass
through costs to consumers. 647 F.2d at 1266-67.

    Again, courts have required OSHA to determine whether a standard
is economically feasible on an industry-by-industry basis. See Air
Contaminants, 965 F.2d at 982 (Ex. #8). Both to meet requirements
for any Regulatory Flexibility Act (5 U.S.C. 603, 604) analysis and
to assure that standards do not threaten the competitive structure
of an industry, OSHA also analyzes the economic impacts on different
size classes within an industry. However, OSHA is not required to
show that all companies within an industry will be able to bear the
burden of compliance or "guarantee the continued existence of
individual employers." Lead I, 647 F.2d at 1265 (Ex. #12) (quoting
Industrial Union Dep't, AFL-CIO v. Hodgson, 499 F.2d 467, 478 (D.C.
Cir. 1974) Ex. #55)).
    As discussed above, OSHA supported its economic feasibility
findings for the 1989 Air Contaminants rule based primarily on the
results of a survey of over 5700 businesses, summarizing the
projected cost of compliance at the two-digit SIC industry sector
level. It found that compliance costs would average less than one
percent of profits, and, alternatively, that prices would increase
by less than one half percent. Nonetheless, the Eleventh Circuit
held that OSHA had failed to meet its burden. The court held that
OSHA was required to show that the rule was economically feasible on
an industry-by industry basis, and that OSHA had not shown that its
analyses at the two-digit SIC industry sector level were appropriate
to meet this burden. Air Contaminants, 965 F.2d at 982. OSHA argued
the generic nature of the rulemaking allowed the agency "a great
latitude in grouping industries in order to estimate 'average'
costs," and that "the costs were sufficiently low per sector to
demonstrate feasibility not only for each sector, but each sub-
sector." Air Contaminants, 965 F.2d at 983. However, the court
found that "average estimates of cost can be extremely misleading
in assessing the impact of particular standards on individual
industries" and observed that "analyzing the economic impact for
an entire sector could conceal particular industries laboring under
special disabilities and likely to fail as a result of
enforcement." Air Contaminants, 965 F.2d at 982. The court allowed
that OSHA could "find and explain that certain impacts and
standards do apply to entire sectors of an industry" if "coupled
with a showing that there are no disproportionately affected
industries within the group." Air Contaminants, 965 F.2d at 982
n.28. But in this case, the court found, OSHA had not explained why
its use of such a "broad grouping was appropriate." Air
Contaminants, 965 F.2d at 983; Ex. #8.
    Ultimately, the court held that OSHA did not sufficiently
explain or support its threshold determination that exposures above
the new PELs posed significant risks of material health impairment,
or that the new PELs eliminated or reduced the risks to the extent
feasible. Finding that "OSHA's overall approach to this rulemaking
is . . . flawed," the court vacated the entire Air Contaminant
rulemaking, rather than just the 23 chemicals that were contested by
union and industry representatives. Air Contaminants, 965 F.2d at
987(Ex. #8).
    The Eleventh Circuit denied OSHA's petition for rehearing. No
longer having a basis to enforce the 1989 PELs, OSHA directed its
compliance officers to stop enforcing the updated limits through a
memo, which was followed by a Federal Register Notice on June 30,
1993, revoking the new limits. 58 FR 35338-35351; (Ex. #19).

Appendix B: 1989 PELs Table

                                                        Table Z-1-A--Limits For Air Contaminants
                                                      [From the vacated 1989 final rule--Ex. #149]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                    TWA                  STEL                 Ceiling
                 Substance                             Cas No.            ------------------------------------------------------------------     Skin
                                                                              ppm      mg/m\3\      ppm      mg/m\3\      ppm      mg/m\3\   Designation
--------------------------------------------------------------------------------------------------------------------------------------------------------
Acetaldehyde..............................  75-07-0......................        100        180        150        270  .........  .........  ...........
Acetic acid...............................  64-19-7......................         10         25  .........  .........  .........  .........  ...........
Acetic anhydride..........................  108-24-7.....................  .........  .........  .........  .........          5         20  ...........
Acetone...................................  67-64-1......................        750       1800       1000      24006  .........  .........  ...........
Acetonitrile..............................  75-05-8......................         40         70         60        105  .........  .........  ...........
2-Acetylamino-fluorine; see 1910.1014.....  53-96-3......................
Acetylene dichloride; see 1,2-              540-59-0.....................
 Dichloroethylene.
Acetylene tetrabromide....................  79-27-6......................          1         14  .........  .........  .........  .........  ...........
Acetylsalicylic acid (Aspirin)............  50-78-2......................  .........          5  .........  .........  .........  .........  ...........
Acrolein..................................  107-02-8.....................        0.1       0.25        0.3        0.8  .........  .........  ...........
Acrylamide................................  79-06-1......................  .........       0.03  .........  .........  .........  .........           X
Acrylic acid..............................  79-10-7......................         10         30  .........  .........  .........  .........           X
Acrylonitrile; see 1910.1045..............  107-13-1.....................  .........  .........  .........  .........  .........  .........  ...........
Aldrin....................................  309-00-2.....................  .........       0.25  .........  .........  .........  .........           X
Allyl alcohol.............................  107-18-6.....................          2          5          4         10  .........  .........           X
Allyl chloride............................  107-05-1.....................          1          3          2          6  .........  .........  ...........
Allyl glycidyl ether (AGE)................  106-92-3.....................          5         22         10         44  .........  .........  ...........
Allyl propyl disulfide....................  2179-59-1....................          2         12          3         18  .........  .........  ...........
alpha-Alumina.............................  1344-28-1....................  .........  .........  .........  .........  .........  .........  ...........
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Aluminum (as Al) Metal....................  7429-90-5.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
                                            Pyro powders.................  .........          5  .........  .........  .........  .........  ...........
                                            Welding fumes................  .........          5  .........  .........  .........  .........  ...........
                                            Soluble salts................  .........          2  .........  .........  .........  .........  ...........
                                            Alkyls.......................  .........          2  .........  .........  .........  .........  ...........
4-Aminodiphenyl; see 1910.1011............  92-67-1.
2-Aminoethanol; see Ethanolamine..........  141-43-5.
2-Aminopyridine...........................  504-29-0.....................        0.5          2  .........  .........  .........  .........  ...........
Amitrole..................................  61-82-5......................  .........        0.2  .........  .........  .........  .........  ...........
Ammonia...................................  7664-41-7....................  .........  .........         35         27  .........  .........  ...........
Ammonium chloride fume....................  12125-02-9...................  .........         10  .........         20  .........  .........  ...........
Ammonium sulfamate........................  7773-06-0.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
n-Amyl acetate............................  628-63-7.....................        100        525  .........  .........  .........  .........  ...........
Sec-Amyl acetate..........................  626-38-0.....................        125        650  .........  .........  .........  .........  ...........
Aniline and homologs......................  62-53-3......................          2          8  .........  .........  .........  .........           X
Anisidine (o-, p-isomers).................  29191-52-4...................  .........        0.5  .........  .........  .........  .........  ...........
Antimony and compounds (as Sb)............  7440-36-0....................  .........        0.5  .........  .........  .........  .........  ...........
ANTU (alpha naphthyl-thiourea)............  86-88-4......................  .........        0.3  .........  .........  .........  .........  ...........
Arsenic, organic compounds (as As)........  7440-38-2....................  .........        0.5  .........  .........  .........  .........  ...........
Arsenic, inorganic compounds (as As); see   Varies with compound.........  .........  .........  .........  .........  .........  .........  ...........
 1910.1018.
Arsine....................................  7784-42-1....................       0.05        0.2  .........  .........  .........  .........  ...........
Asbestos; see 1910.1001...................  Varies.......................  .........  .........  .........  .........  .........  .........  ...........
Atrazine..................................  1912-24-9....................  .........          5  .........  .........  .........  .........  ...........
Azinphos-methyl...........................  86-50-0......................  .........        0.2  .........  .........  .........  .........           X
Barium, soluble compounds.................  7440-39-3....................  .........        0.5  .........  .........  .........  .........  ...........
Barium sulfate............................  7727-43-7.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Benomyl...................................  17804-35-2.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Benzene; see 1910.1028. See Table Z-2 for   71-43-2.
 the limits applicable in the operations
 or sectors excluded in 1910.1028.
Benzidine; see 1910.1010..................  92-87-5.
p-Benzoquinone; see Quinone...............  106-51-4.
Benzo(a)pyrene; see Coal tar pitch
 volatiles
Benzoyl peroxide..........................  94-36-0......................  .........          5  .........  .........  .........  .........  ...........
Benzyl chloride...........................  100-44-7.....................          1          5  .........  .........  .........  .........  ...........
Beryllium and beryllium compounds (as Be).  7440-41-7....................      0.002  .........    \1\.005  .........      0.025  .........  ...........
Biphenyl; see Diphenyl....................  92-52-4.
Bismuth telluride, undoped................  1304-82-1.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Bismuth telluride, Se-doped...............  1304-82-1....................  .........          5  .........  .........  .........  .........  ...........
Borates, tetra, sodium salts:
    Anhydrous.............................  1330-43-4....................  .........  .........         10  .........  .........  .........  ...........
    Decahydrate...........................  1303-96-4....................  .........  .........         10  .........  .........  .........  ...........
    Penta-hydrate.........................  12179-04-3...................  .........  .........         10  .........  .........  .........  ...........
Boron oxide...............................  1303-86-2.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable Fraction..........  .........          5  .........  .........  .........  .........  ...........
Boron tribromide..........................  10294-33-4...................  .........  .........  .........  .........          1         10  ...........
Boron trifluoride.........................  7637-07-2....................  .........  .........  .........  .........          1          3  ...........
Bromacil..................................  314-40-9.....................          1         10  .........  .........  .........  .........  ...........
Bromine...................................  7726-95-6....................        0.1        0.7        0.3          2  .........  .........  ...........
Bromine pentafluoride.....................  7789-30-2....................        0.1        0.7  .........  .........  .........  .........  ...........
Bromoform.................................  75-25-2......................        0.5          5  .........  .........  .........  .........           X
Butadiene (1,3- Butadiene); see 1910.1051.  106-99-0.
Butane....................................  106-97-8.....................        800       1900  .........  .........  .........  .........  ...........
Butanethiol; see Butyl mercaptan..........  109-79-5.
2-Butanone (Methyl ethyl ketone)..........  78-93-3......................        200        590        300        885  .........  .........  ...........
2-Butoxyethanol...........................  111-76-2.....................         25        120  .........  .........  .........  .........           X
n-Butyl-acetate...........................  123-86-4.....................        150        710        200        950  .........  .........  ...........
sec-Butyl acetate.........................  105-46-4.....................        200        950  .........  .........  .........  .........  ...........
tert-Butyl acetate........................  540-88-5.....................        200        950  .........  .........  .........  .........  ...........
Butyl acrylate............................  141-32-2.....................         10         55  .........  .........  .........  .........  ...........
n-Butyl alcohol...........................  71-36-3......................  .........  .........  .........  .........         50        150           X
sec-Butyl alcohol.........................  78-92-2......................        100        305  .........  .........  .........  .........  ...........
tert-Butyl alcohol........................  75-65-0......................        100        300        150        450  .........  .........  ...........
Butylamine................................  109-73-9.....................  .........  .........  .........  .........          5         15           X
tert-Butyl Chromate (as CrO3).............  1189-85-1....................  .........  .........  .........  .........  .........        0.1           X
n-Butyl glycidyl ether (BGE)..............  2426-08-6....................         25        135  .........  .........  .........  .........  ...........
n-Butyl lactate...........................  138-22-7.....................          5         25  .........  .........  .........  .........  ...........
Butyl mercaptan...........................  109-79-5.....................        0.5        1.5  .........  .........  .........  .........  ...........
o-sec-Butylphenol.........................  89-72-5......................          5         30  .........  .........  .........  .........           X
p-tert-Butyltoluene.......................  98-51-1......................         10         60         20        120  .........  .........  ...........
Cadmium (all forms, as Cd); see 1910.1027   7440-43-9.
 See Table Z-2 for the limits applicable
 in the operations or sectors excluded in
 1910.1027.
Calcium carbonate.........................  1317-65-3.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Calcium cyanamide.........................  156-62-7.....................  .........        0.5  .........  .........  .........  .........  ...........
Calcium hydroxide; see particulates not     1305-62-0....................  .........          5  .........  .........  .........  .........  ...........
 otherwise regulated.
Calcium oxide.............................  1305-78-8....................  .........          5  .........  .........  .........  .........  ...........
Calcium silicate..........................  1344-95-2....................  .........  .........  .........  .........  .........  .........  ...........
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Calcium sulfate...........................  7778-18-9.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Camphor, synthetic........................  76-22-2.
Camphor, synthetic........................  76-22-2......................  .........          2  .........  .........  .........  .........  ...........
Caprolactam...............................  105-60-2.
                                            Dust.........................  .........          1  .........          3  .........  .........  ...........
                                            Vapor........................          5         20         10         40  .........  .........  ...........
Captafol (Difolatan[supreg])..............  2425-06-1....................  .........        0.1  .........  .........  .........  .........  ...........
Captan....................................  133-06-2.....................  .........          5  .........  .........  .........  .........  ...........
Carbaryl (Sevin[supreg])..................  63-25-2......................  .........          5  .........  .........  .........  .........  ...........
Carbofuran (Furadan[supreg])..............  1563-66-2....................  .........        0.1  .........  .........  .........  .........  ...........
Carbon black..............................  1333-86-4....................  .........        3.5  .........  .........  .........  .........  ...........
Carbon dioxide............................  124-38-9.....................     10,000     18,000     30,000     54,000  .........  .........  ...........
                                                                                                         0          0
Carbon disulfide..........................  75-15-0......................          4         12         12         36  .........  .........           X
Carbon monoxide...........................  630-08-0.....................         35         40  .........  .........        200        229  ...........
Carbon tetrabromide.......................  558-13-4.....................        0.1        1.4        0.3          4  .........  .........  ...........
Carbon tetrachloride......................  56-23-5......................          2       12.6  .........  .........  .........  .........  ...........
Carbonyl fluoride.........................  353-50-4.....................          2          5          5         15  .........  .........  ...........
Catechol (Pyrocatechol)...................  120-80-9.....................          5         20  .........  .........  .........  .........           X
Cellulose.................................  9004-34-6.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Cesium hydroxide..........................  21351-79-1...................  .........          2  .........  .........  .........  .........  ...........
Chlordane.................................  57-74-9......................  .........        0.5  .........  .........  .........  .........           X
Chlorinated camphene......................  8001-35-2....................  .........        0.5  .........          1  .........  .........           X
Chlorinated diphenyl oxide................  55720-99-5...................  .........        0.5  .........  .........  .........  .........  ...........
Chlorine..................................  7782-50-5....................        0.5        1.5          1          3  .........  .........  ...........
Chlorine dioxide..........................  10049-04-4...................        0.1        0.3        0.3        0.9  .........  .........  ...........
Chlorine trifluoride......................  7790-91-2....................  .........  .........  .........  .........        0.1        0.4  ...........
Chloro-acetaldehyde.......................  107-20-0.....................  .........  .........  .........  .........          1          3  ...........
alpha-Chloroaceto-phenone (Phenacy1         532-27-4.....................       0.05        0.3  .........  .........  .........  .........  ...........
 chloride).
Chloroacetyl chloride.....................  79-04-9......................       0.05        0.2  .........  .........  .........  .........  ...........
Chlorobenzene.............................  108-90-7.....................         75        350  .........  .........  .........  .........  ...........
o-Chloro-benzylidene malononitrile........  2698-41-1....................  .........  .........  .........  .........       0.05        0.4           X
Chloro-bromomethane.......................  74-97-5......................        200       1050  .........  .........  .........  .........  ...........
2-Chloro-1,3-butadiene; see beta-           126-99-8.....................  .........  .........  .........  .........  .........  .........  ...........
 Chloroprene.
Chloro-difluoromethane....................  75-45-6......................       1000       3500  .........  .........  .........  .........  ...........
Chlorodiphenyl (42% Chlorine) (PCB).......  53469-21-9...................  .........          1  .........  .........  .........  .........           X
Chlorodiphenyl (54% Chlorine) (PCB).......  11097-69-1...................  .........        0.5  .........  .........  .........  .........           X
1-Chloro,2,3-epoxypropane; see              106-89-8.
 Epichlorohydrin.
2-Chloroethanol; see Ethylene chlorohydrin  107-07-3.
Chloroethylene; see Vinyl chloride........  75-01-4.
Chloroform (Trichloro-methane)............  67-66-3......................          2       9.78  .........  .........  .........  .........  ...........
bis(Chloro-methyl) ether; see 1910.1008...  542-88-1.
Chloromethyl methyl ether; see 1910.1006..  107-30-2.
1-Chloro-l-nitropropane...................  600-25-9.....................          2         10  .........  .........  .........  .........  ...........
Chloropenta-fluoroethane..................  76-15-3......................       1000       6320  .........  .........  .........  .........  ...........
Chloropicrin..............................  76-06-2......................        0.1        0.7  .........  .........  .........  .........  ...........
beta-Chloroprene..........................  126-99-8.....................         10         35  .........  .........  .........  .........           X
o-Chlorostyrene...........................  2039-87-4....................         50        285         75        428  .........  .........  ...........
o-Chlorotoluene...........................  95-49-8......................         50        250  .........  .........  .........  .........  ...........
2-Chloro-6-trichloro-methyl pyridine......  1929-82-4.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Chlorpyrifos..............................  2921-88-2....................  .........        0.2  .........  .........  .........  .........           X
Chromic acid and chromates (as CrO3); see   Varies with compound.........  .........  .........  .........  .........        0.1  .........  ...........
 1910.1026. See Table Z-2 for the exposure
 limit for any operations or sectors where
 the exposure limit in 1910.1026 is stayed
 or are otherwise not in effect.
Chromium (II) compounds (as Cr)...........  Varies with compound.........  .........        0.5  .........  .........  .........  .........  ...........
Chromium (III) compounds (as Cr)..........  Varies with compound.........  .........        0.5  .........  .........  .........  .........  ...........
Chromium metal and insoluble salts........  7440-47-3....................  .........          1  .........  .........  .........  .........  ...........
Chrysene; see Coal tar pitch volatiles
Clopidol..................................  2971-90-6.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Coal dust (less than 5% Si02), quartz,      N/A..........................  .........          2  .........  .........  .........  .........  ...........
 respirable fraction.
Coal dust (greater than or equal to 5%      N/A..........................  .........        0.1  .........  .........  .........  .........  ...........
 Si02) respirable quartz fraction.
Coal tar pitch volatiles (benzene soluble   8007-45-2....................  .........        0.2  .........  .........  .........  .........  ...........
 fraction), anthracene, BaP, phenanthrene,
 acridine, chrysene, pyrene.
Cobalt metal, dust, and fume (as Co)......  7440-48-4....................  .........       0.05  .........  .........  .........  .........  ...........
Cobalt carbonyl (as Co)...................  10210-68-1...................  .........        0.1  .........  .........  .........  .........  ...........
Cobalt hydrocarbonyl (as Co)..............  16842-03-8...................  .........        0.1  .........  .........  .........  .........  ...........
Coke oven emissions; See 1910.1029
Copper....................................  7440-50-8.
                                            Fume (as Cu).................  .........        0.1  .........  .........  .........  .........  ...........
                                            Dusts and mists (as Cu)......  .........          1  .........  .........  .........  .........  ...........
Cotton dust, raw This 8-hour TWA applies
 to respirable dust as measured by a
 vertical elutriator cotton dust or
 equivalent instrument. The time-weighted
 average applies to the cotton waste
 processing operations of waster recycling
 (sorting, blending, cleaning, and
 willowing) and garnetting. See also
 1910.1043 for cotton dust limits
 applicable to other sectors.
Crag herbicide (Sesone)...................  136-78-7.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Cresol, all isomers.......................  1319-77-3; 95-48-7; 108-39-4;          5         22  .........  .........  .........  .........           X
                                             106-44-5.
Crotonaldehyde............................  123-73-9; 4170-30-3..........  .........          2          6  .........  .........  .........  ...........
Crufomate.................................  106-44-5.....................  .........          5  .........  .........  .........  .........  ...........
Cumene....................................  98-82-8......................         50        245  .........  .........  .........  .........           X
Cyanamide.................................  420-04-2.....................  .........          2  .........  .........  .........  .........  ...........
Cyanides (as CN)..........................  151-50-0.....................  .........          5  .........  .........  .........  .........  ...........
Cyanogen..................................  460-19-5.....................         10         20  .........  .........  .........  .........  ...........
Cyanogen chloride.........................  506-77-4.....................  .........  .........  .........  .........        0.3        0.6  ...........
Cyclohexane...............................  110-82-7.....................        300       1050  .........  .........  .........  .........  ...........
Cyclohexanol..............................  108-93-0.....................         50        200  .........  .........  .........  .........           X
Cyclohexanone.............................  108-94-1.....................         25        100  .........  .........  .........  .........           X
Cyclohexene...............................  110-83-8.....................        300       1015  .........  .........  .........  .........  ...........
Cyclohexylamine...........................  108-91-8.....................         10         40  .........  .........  .........  .........  ...........
Cyclonite.................................  121-82-4.....................  .........        1.5  .........  .........  .........  .........           X
Cyclopentadiene...........................  542-92-7.....................         75        200  .........  .........  .........  .........  ...........
Cyclopentane..............................  287-92-3.....................        600       1720  .........  .........  .........  .........  ...........
Cyhexatin.................................  13121-70-5...................  .........          5  .........  .........  .........  .........  ...........
2,4-D (Dichlorophenoxy-acetic acid).......  94-75-7......................  .........         10  .........  .........  .........  .........  ...........
Decaborane................................  17702-41-9...................       0.05        0.3       0.15        0.9  .........  .........           X
Demeton-(Systox[supreg])..................  8065-48-3....................  .........        0.1  .........  .........  .........  .........           X
Diborane..................................  19207-45-7...................        0.1        0.1  .........  .........  .........  .........  ...........
Dichlorodiphenyltri-chloroethane (DDT)....  50-29-3......................  .........          1  .........  .........  .........  .........           X
Dichlorvos (DDVP).........................  62-73-7......................  .........          1  .........  .........  .........  .........           X
Diacetone alcohol (4-Hydroxy-4-methyl-2-    123-42-2.....................         50        240  .........  .........  .........  .........  ...........
 pentanone).
1,2-Diaminoethane; see Ethylenediamine....  107-15-3.
Diazinon..................................  333-41-5.....................  .........        0.1  .........  .........  .........  .........           X
Diazomethane..............................  334-88-3.....................        0.2        0.4  .........  .........  .........  .........  ...........
1,2-Dibromo-3-chloropropane; see 1910.1044  96-12-8.
2-N-Dibutylamino-ethanol..................  102-81-8.....................          2         14  .........  .........  .........  .........  ...........
Dibutyl phosphate.........................  107-66-4.....................          1          5          2         10  .........  .........  ...........
Dibutyl phthalate.........................  84-74-2......................  .........          5  .........  .........  .........  .........  ...........
Dichloro-acetylene........................  7572-29-4....................  .........  .........  .........  .........        0.1        0.4  ...........
o-Dichlorobenzene.........................  95-50-1......................  .........  .........  .........  .........         50        300  ...........
p-Dichlorobenzene.........................  106-46-7.....................         75        450        110        675  .........  .........  ...........
3,3'-Dichloro-benzidine; see 1910.1007....  91-94-1.
Dichlorodifluoro-methane..................  75-71-8......................       1000       4950  .........  .........  .........  .........  ...........
1,3-Dichloro-5,5-dimethyl hydantoin.......  118-52-5.....................  .........        0.2  .........        0.4  .........  .........  ...........
1,1-Dichloroethane........................  75-34-3......................        100        400  .........  .........  .........  .........  ...........
1,2-Dichloroethylene......................  540-59-0.....................        200        790  .........  .........  .........  .........  ...........
Dichloroethyl ether.......................  111-44-4.....................          5         30         10         60  .........  .........           X
Dichloro-methane; see Methylene chloride..  75-09-2.
Dichloromono-fluoromethane................  75-43-4......................         10         40  .........  .........  .........  .........  ...........
1,1-Dichloro- 1-nitroethane...............  594-72-9.....................          2         10  .........  .........  .........  .........  ...........
1,2-Dichloropropane; see Propylene          78-87-5.
 dichloride.
1,3-Dichloropropene.......................  542-75-6.....................          1          5  .........  .........  .........  .........           X
2,2-Dichloro-propionic acid...............  75-99-0......................          1          6  .........  .........  .........  .........  ...........
Dichloro-tetrafluoroethane................  76-14-2......................       1000       7000  .........  .........  .........  .........  ...........
Dicrotophos...............................  141-66-2.....................  .........       0.25  .........  .........  .........  .........           X
Dicyclo-pentadiene........................  77-73-6......................          5         30  .........  .........  .........  .........  ...........
Dicyclo-pentadienyl iron..................  102-54-5.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Dieldrin..................................  60-57-1......................  .........       0.25  .........  .........  .........  .........           X
Diethanolamine............................  111-42-2.....................          3         15  .........  .........  .........  .........  ...........
Diethylamine..............................  109-89-7.....................         10         30         25         75  .........  .........  ...........
2-Diethylamino-ethanol....................  100-37-8.....................         10         50  .........  .........  .........  .........  ...........
Diethylene triamine.......................  111-40-0.....................          1          4  .........  .........  .........  .........  ...........
Diethyl ether; see Ethyl ether............  60-29-7.
Diethyl ketone............................  96-22-0......................        200        705  .........  .........  .........  .........  ...........
Diethyl phthalate.........................  84-66-2......................  .........          5  .........  .........  .........  .........  ...........
Difluorodibromo-methane...................  75-61-6......................        100        860  .........  .........  .........  .........  ...........
Diglycidyl ether (DGE)....................  2238-07-5....................        0.1        0.5  .........  .........  .........  .........  ...........
Dihydroxy-benzene; see Hydroquinone.......  123-31-9.
Diisobutyl ketone.........................  108-83-8.....................         25        150  .........  .........  .........  .........  ...........
Diisopropylamine..........................  108-18-9.....................          5         20  .........  .........  .........  .........           X
4-Dimethylamino-azobenzene; see 1910.1015.  60-11-7.
Dimethoxy-methane; see Methylal...........  109-87-5.
Dimethyl acetamide........................  127-19-5.....................         10         35  .........  .........  .........  .........           X
Dimethylamine.............................  124-40-3.....................         10         18  .........  .........  .........  .........  ...........
Dimethylamino-benzene; see Xylidine.......  1300-73-8.
Dimethylaniline (N,N-Dimethylaniline).....  121-69-7.....................          5         25         10         50  .........  .........           X
Dimethyl-benzene; see Xylene..............  Varies with isomer.
Dimethyl-1,2-dibromo-2,2-dichloroethyl      300-76-5.....................  .........          3  .........  .........  .........  .........           X
 phosphate.
Dimethyl-formamide........................  68-12-2......................         10         30  .........  .........  .........  .........           X
2,6-Dimethyl-4-heptanone; see Diisobutyl    108-83-8.
 ketone.
1,1-Dimethyl-hydrazine....................  57-14-7......................        0.5          1  .........  .........  .........  .........           X
Dimethyl-phthalate........................  131-11-3.....................  .........          5  .........  .........  .........  .........  ...........
Dimethyl sulfate..........................  77-78-1......................        0.1        0.5  .........  .........  .........  .........           X
Dinitolmide (3,5-Dinitro-o-toluamide).....  148-01-6.....................  .........          5  .........  .........  .........  .........  ...........
Dinitrobenzene (all isomers)..............  (alpha): 528-29-0............  .........          1  .........  .........  .........  .........           X
                                            (meta): 99-65-0..............
                                            (para-): 100-25-4............
Dinitro-o-cresol..........................  534-52-1.....................  .........        0.2  .........  .........  .........  .........           X
Dinitrotoluene............................  121-14-2.....................  .........        1.5  .........  .........  .........  .........           X
Dioxane (Diethylene dioxide)..............  123-91-1.....................         25         90  .........  .........  .........  .........           X
Dioxathion (Delnav).......................  78-34-2......................  .........        0.2  .........  .........  .........  .........           X
Diphenyl (Biphenyl).......................  92-52-4......................        0.2          1  .........  .........  .........  .........  ...........
Diphenylamine.............................  122-39-4.....................  .........         10  .........  .........  .........  .........  ...........
Diphenylmethane diisocyanate; see           101-68-8.
 Methylene bisphenyl isocyanate.
Dipropylene glycol methyl ether...........  34590-94-8...................        100        600        150        900  .........  .........           X
Dipropyl ketone...........................  123-19-3.....................         50        235  .........  .........  .........  .........  ...........
Diquat....................................  85-00-7......................  .........        0.5  .........  .........  .........  .........  ...........
Di-sec octyl phthalate (Di-2-ethylhexyl     117-81-7.....................  .........          5  .........         10  .........  .........  ...........
 phthalate).
Disulfiram................................  97-77-8......................  .........          2  .........  .........  .........  .........  ...........
Disulfoton................................  298-04-4.....................  .........        0.1  .........  .........  .........  .........           X
2,6-Di-tert-butyl-p-cresol................  128-37-0.....................  .........         10  .........  .........  .........  .........  ...........
Diuron....................................  330-54-1.....................  .........         10  .........  .........  .........  .........  ...........
Divinyl benzene...........................  108-576......................         10         50  .........  .........  .........  .........  ...........
Emery.....................................  112-62-9.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Endosulfan................................  115-29-7.....................  .........        0.1  .........  .........  .........  .........           X
Endrin....................................  72-20-8......................  .........        0.1  .........  .........  .........  .........           X
Epichlorohydrin...........................  106-89-8.....................          2          8  .........  .........  .........  .........           X
EPN.......................................  2104-64-5....................  .........        0.5  .........  .........  .........  .........           X
1,2-Epoxypropane; see Propylene oxide.....  75-56-9.
2,3-Epoxy-l-propanol; see Glycidol........  556-52-5.
Ethanethiol; see Ethyl mercaptan..........  75-08-1.
Ethanolamine..............................  141-43-5.....................          3          8          6         15  .........  .........  ...........
Ethion....................................  563-12-2.....................  .........        0.4  .........  .........  .........  .........           X
2-Ethoxyethanol [In Process of 6(b)         110-80-5.
 Rulemaking].
2-Ethoxyethyl acetate (Cellosolve acetate)  111-15-9.
 [In Process of 6(b) Rulemaking].
Ethyl acetate.............................  141-78-6.....................        400       1400  .........  .........  .........  .........  ...........
Ethyl acrylate............................  140-88-5.....................          5         20         25        100  .........  .........           X
Ethyl alcohol (Ethanol)...................  64-17-5......................       1000       1900  .........  .........  .........  .........  ...........
Ethylamine................................  75-04-7......................         10         18  .........  .........  .........  .........  ...........
Ethyl amyl ketone (5-Methyl-3-heptanone)..  106-68-3.....................         25        130  .........  .........  .........  .........  ...........
Ethyl benzene.............................  100-41-4.....................        100        435        125        545  .........  .........  ...........
Ethyl bromide.............................  74-96-4......................        200        890        250       1110  .........  .........  ...........
Ethyl butyl ketone (3-Heptanone)..........  106-35-4.....................         50        230  .........  .........  .........  .........  ...........
Ethyl chloride............................  75-00-3......................       1000       2600  .........  .........  .........  .........  ...........
Ethyl ether...............................  60-29-7......................        400       1200        500       1500  .........  .........  ...........
Ethyl formate.............................  109-94-4.....................        100        300  .........  .........  .........  .........  ...........
Ethyl mercaptan...........................  75-08-1......................        0.5          1  .........  .........  .........  .........  ...........
Ethyl silicate............................  78-10-4......................         10         85  .........  .........  .........  .........  ...........
Ethylene chlorohydrin.....................  107-07-3.....................  .........  .........  .........  .........          1          3           X
Ethylenediamine...........................  107-15-3.....................         10         25  .........  .........  .........  .........  ...........
Ethylene dibromide; see Table Z-2.........  106-93-4.
Ethylene dichloride.......................  107-06-2.....................          1          4          2          8  .........  .........  ...........
Ethylene glycol...........................  107-21-1.....................  .........  .........  .........  .........         50        125  ...........
Ethylene glycol dinitrate.................  628-96-6.....................  .........  .........  .........        0.1  .........  .........           X
Ethylene glycol methyl acetate; see Methyl  110-49-6.
 cellosolve acetate.
Ethyleneimine; see 1910.1012..............  151-56-4.
Ethylene oxide; see 1910.1047.............  75-21-8.
Ethylidene chloride; see 1,1-               75-34-3.
 Dichloroethane.
Ethylidene norbornene.....................  16219-75-3...................  .........  .........  .........  .........          5         25  ...........
N-Ethylmorpholine.........................  100-74-3.....................          5         23  .........  .........  .........  .........           X
Fenamiphos................................  22224-92-6...................  .........        0.1  .........  .........  .........  .........           X
Fensulfothion (Dasanit)...................  115-90-2.....................  .........        0.1  .........  .........  .........  .........  ...........
Fenthion..................................  55-38-9......................  .........        0.2  .........  .........  .........  .........           X
Ferbam....................................  14484-64-1.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Ferrovanadium dust........................  12604-58-9...................  .........          1  .........          3  .........  .........  ...........
Fluorides (as F)..........................  Varies with compound.........  .........        2.5  .........  .........  .........  .........  ...........
Fluorine..................................  7782-41-4....................        0.1        0.2  .........  .........  .........  .........  ...........
Fluoro-trichloromethane (Trichlorofluoro-   75-69-4......................  .........  .........  .........  .........       1000       5600  ...........
 methane).
Fonofos...................................  944-22-9.....................  .........        0.1  .........  .........  .........  .........           X
Formaldehyde; see 1910.1048...............  50-00-0.
Formamide.................................  75-12-7......................         20         30         30         45  .........  .........  ...........
Formic acid...............................  64-18-6......................          5          9  .........  .........  .........  .........  ...........
Furfural..................................  98-01-1......................          2          8  .........  .........  .........  .........           X
Furfuryl alcohol..........................  98-00-0......................         10         40         15         60  .........  .........           X
Gasoline..................................  8006-61-9....................        300        900        500       1500  .........  .........  ...........
Gemanium tetrahydride.....................  7782-65-2....................        0.2        0.6  .........  .........  .........  .........  ...........
Glutaraldehyde............................  111-30-8.....................  .........  .........  .........  .........        0.2        0.8  ...........
Glycerin (mist)...........................  56-81-5.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Glycidol..................................  556-52-5.....................         25         75  .........  .........  .........  .........  ...........
Glycol monoethyl ether; see 2-              110-80-5.
 Ethoxyethanol.
Grain dust (oat, wheat, barley)...........  N/A..........................  .........         10  .........  .........  .........  .........  ...........
Graphite, natural respirable dust.........  7782-42-5....................  .........        2.5  .........  .........  .........  .........  ...........
Graphite, synthetic.......................  N/A.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Guthion[supreg]; see Azinphos methyl......  86-50-0.
Gypsum....................................  7778-18-9.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Hafnium...................................  7440-58-6....................  .........        0.5  .........  .........  .........  .........  ...........
Heptachlor................................  76-44-8......................  .........        0.5  .........  .........  .........  .........           X
Heptane (n-Heptane).......................  142-82-5.....................        400       1600        500       2000  .........  .........  ...........
Hexachloro-butadiene......................  87-68-3......................       0.02       0.24  .........  .........  .........  .........  ...........
Hexachlorocyclo-pentadiene................  77-47-4......................       0.01        0.1  .........  .........  .........  .........  ...........
Hexa-chloroethane.........................  67-72-1......................          1         10  .........  .........  .........  .........           X
Hexachloro-naphthalene....................  1335-87-1....................  .........        0.2  .........  .........  .........  .........           X
Hexafluoro-acetone........................  684-16-2.....................        0.1        0.7  .........  .........  .........  .........           X
n-Hexane..................................  110-54-3.....................         50        180  .........  .........  .........  .........  ...........
Hexane isomers............................  Varies with compound.........        500       1800       1000       3600  .........  .........  ...........
2-Hexanone (Methyl n-butyl ketone)........  591-78-6.....................          5         20  .........  .........  .........  .........  ...........
Hexone (Methyl isobutyl ketone)...........  108-10-1.....................         50        205         75        300  .........  .........  ...........
sec-Hexyl acetate.........................  108-84-9.....................         50        300  .........  .........  .........  .........  ...........
Hexylene glycol...........................  107-41-5.....................  .........  .........  .........  .........         25        125  ...........
Hydrazine.................................  302-01-2.....................        0.1        0.1  .........  .........  .........  .........           X
Hydrogenated terphenyls...................  61788-32-7...................        0.5          5  .........  .........  .........  .........  ...........
Hydrogen bromide..........................  10035-10-6...................  .........  .........  .........  .........          3         10  ...........
Hydrogen chloride.........................  7647-01-0....................  .........  .........  .........  .........          5          7  ...........
Hydrogen cyanide..........................  74-90-8......................  .........  .........        4.7          5  .........  .........           X
Hydrogen fluoride (as F)..................  7664-39-3....................          3  .........          6  .........  .........  .........  ...........
Hydrogen peroxide.........................  7722-84-1....................          1        1.4  .........  .........  .........  .........  ...........
Hydrogen selenide (as Se).................  7783-07-5....................       0.05        0.2  .........  .........  .........  .........  ...........
Hydrogen sulfide..........................  7783-06-4....................         10         14         15         21  .........  .........  ...........
Hydroquinone..............................  123-31-9.....................  .........          2  .........  .........  .........  .........  ...........
2-Hydroxypropyl acrylate..................  999-61-1.....................        0.5          3  .........  .........  .........  .........           X
Indene....................................  95-13-6......................         10         45  .........  .........  .........  .........  ...........
Indium and compounds (as In)..............  7440-74-6....................  .........        0.1  .........  .........  .........  .........  ...........
Iodine....................................  7553-56-2....................  .........  .........  .........  .........        0.1          1  ...........
Iodoform..................................  75-47-8......................        0.6         10  .........  .........  .........  .........  ...........
Iron oxide (dust and fume as Fe) Total      1309-37-1....................  .........         10  .........  .........  .........  .........  ...........
 particulate.
Iron pentacarbonyl (as Fe)................  13463-40-6...................        0.1        0.8        0.2        1.6  .........  .........  ...........
Iron salts (soluble) (as Fe)..............  Varies with compound.........  .........          1  .........  .........  .........  .........  ...........
Isoamyl acetate...........................  123-92-2.....................        100        525  .........  .........  .........  .........  ...........
Isoamyl alcohol (primary and secondary)...  123-51-3.....................        100        360        125        450  .........  .........  ...........
Isobutyl acetate..........................  110-19-0.....................        150        700  .........  .........  .........  .........  ...........
Isobutyl alcohol..........................  78-83-1......................         50        150  .........  .........  .........  .........  ...........
Isooctyl alcohol..........................  26952-21-6...................         50        270  .........  .........  .........  .........           X
Isophorone................................  78-59-1......................          4         23  .........  .........  .........  .........  ...........
Isophorone diisocyanate...................  4098-71-9....................      0.005  .........       0.02  .........  .........  .........           X
2-Isopropoxy-ethanol......................  109-59-1.....................         25        105  .........  .........  .........  .........  ...........
Isopropyl acetate.........................  108-21-4.....................        250        950        310       1185  .........  .........  ...........
Isopropyl alcohol.........................  67-63-0......................        400        980        500       1225  .........  .........  ...........
Isopropylamine............................  75-31-0......................          5         12         10         24  .........  .........  ...........
N-Isopropylaniline........................  768-52-5.....................          2         10  .........  .........  .........  .........           X
Isopropyl ether...........................  108-20-3.....................        500       2100  .........  .........  .........  .........  ...........
Isopropyl glycidyl ether (IGE)............  4016-14-2....................         50        240         75        360  .........  .........  ...........
Kaolin....................................  N/A.                           .........  .........  .........  .........  .........  .........  ...........
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Ketene....................................  463-51-4.....................        0.5        0.9        1.5          3  .........  .........  ...........
Lead inorganic (as Pb); see 1910.1025.....  7439-92-1.
Limestone.................................  1317-65-3.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Lindane...................................  58-89-9......................  .........        0.5  .........  .........  .........  .........           X
Lithium hydride...........................  7580-67-8....................  .........      0.025  .........  .........  .........  .........  ...........
L.P.G. (Liquefied petroleum gas)..........  68476-85-7...................       1000       1800  .........  .........  .........  .........  ...........
Magnesite.................................  546-93-0.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Magnesium oxide fume, total particulate...  1309-48-4.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Malathion.................................  121-75-5.
                                            Total dust...................  .........         10  .........  .........  .........  .........           X
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........           X
Maleic anhydride..........................  108-31-6.....................       0.25          1  .........  .........  .........  .........  ...........
Manganese compounds (as Mn)...............  7439-96-5....................  .........  .........  .........  .........  .........          5  ...........
Manganese fume (as Mn)....................  7439-96-5....................  .........          1  .........          3  .........  .........  ...........
Manganese cyclopentadienyl tricarbonyl (as  12079-65-1...................  .........        0.1  .........  .........  .........  .........           X
 Mn).
Manganese tetroxide (as Mn)...............  1317-35-7....................  .........          1  .........  .........  .........  .........  ...........
Marble....................................  1317-65-3.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Mercury (aryl and inorganic) (as Hg)......  7439-97-6....................  .........  .........  .........  .........  .........        0.1           X
Mercury (organo) alkyl compounds (as Hg)..  7439-97-6....................  .........       0.01  .........       0.03  .........  .........           X
Mercury (vapor) (as Hg)...................  7439-97-6....................  .........       0.05  .........  .........  .........  .........           X
Mesityl oxide.............................  141-79-7.....................         15         60         25        100  .........  .........  ...........
Methacrylic acid..........................  79-41-4......................         20         70  .........  .........  .........  .........           X
Methanethiol; see Methyl mercaptan........  74-93-1.
Methomyl (Lannate)........................  16752-77-5...................  .........        2.5  .........  .........  .........  .........  ...........
Methoxychlor..............................  72-43-5.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
2-Methoxyethanol; see Methyl cellosolve...  109-86-4.
4-Methoxyphenol...........................  150-76-5.....................  .........          5  .........  .........  .........  .........  ...........
Methyl acetate............................  79-20-9......................        200        610        250        760  .........  .........  ...........
Methyl acetylene (Propyne)................  74-99-7......................       1000       1650  .........  .........  .........  .........  ...........
Methyl acetylene-propadiene mixture (MAPP)  .............................       1000       1800       1250       2250  .........  .........  ...........
Methyl acrylate...........................  96-33-3......................         10         35  .........  .........  .........  .........           X
Methyl-acrylonitrile......................  126-98-7.....................          1          3  .........  .........  .........  .........           X
Methylal (Dimethoxy-methane)..............  109-87-5.....................       1000       3100  .........  .........  .........  .........  ...........
Methyl alcohol............................  67-56-1......................        200        260        250        325  .........  .........           X
Methylamine...............................  74-89-5......................         10         12  .........  .........  .........  .........  ...........
Methyl amyl alcohol; see Methyl isobutyl    108-11-2.
 carbinol.
Methyl n-amyl ketone......................  110-43-0.....................        100        465  .........  .........  .........  .........  ...........
Methyl bromide............................  74-83-9......................          5         20  .........  .........  .........  .........           X
Methyl butyl ketone; see 2-Hexanone.......  591-78-6.
Methyl cellosolve (2-Methoxyethanol)......  109-86-4.....................         25         80  .........  .........  .........  .........           X
Methyl cellosolve acetate (2-Methoxyethyl   110-49-6.....................         25        120  .........  .........  .........  .........           X
 acetate).
Methyl chloride...........................  74-87-3......................         50        105        100        210  .........  .........  ...........
Methyl chloroform (1,1,1-Trichloroethane).  71-55-6......................        350       1900        450       2450  .........  .........  ...........
Methyl 2-cyanoacrylate....................  137-05-3.....................          2          8          4         16  .........  .........  ...........
Methyl cyclohexane........................  108-87-2.....................        400       1600  .........  .........  .........  .........  ...........
Methyl-cyclohexanol.......................  25639-42-3...................         50        235  .........  .........  .........  .........  ...........
o-Methylcyclo-hexanone....................  583-60-8.....................         50        230         75        345  .........  .........           X
Methylcyclo-pentadienyl manganese           12108-13-3...................  .........        0.2  .........  .........  .........  .........           X
 tricarbonyl (as Mn).
Methyl demeton............................  8022-00-2....................  .........        0.5  .........  .........  .........  .........           X
4,4'-Methylene bis(2-chloroaniline)         101-14-4.....................       0.02       0.22  .........  .........  .........  .........           X
 (MBOCA).
Methylene bis(4-cyclo-hexylisocyanate)....  5124-30-1....................  .........  .........  .........  .........       0.01       0.11           X
Methylene chloride; see 1910.1052.........  75-09-2.
Methylene-dianiline; see 1910.1050........  101-77-9.
Methyl ethyl ketone peroxide (MEKP).......  1338-23-4....................  .........  .........  .........  .........        0.7          5  ...........
Methyl formate............................  107-31-3.....................        100        250        150        375  .........  .........  ...........
Methyl hydrazine (Monomethyl hydrazine)...  60-34-4......................  .........  .........  .........  .........        0.2       0.35           X
Methyl iodide.............................  74-88-4......................          2         10  .........  .........  .........  .........           X
Methyl isoamyl ketone.....................  110-12-3.....................         50        240  .........  .........  .........  .........  ...........
Methyl isobutyl carbinol..................  108-11-2.....................         25        100         40        165  .........  .........           X
Methyl isobutyl ketone; see Hexone........  108-10-1.
Methyl isocyanate.........................  624-83-9.....................       0.02       0.05  .........  .........  .........  .........           X
Methyl isopropyl ketone...................  563-80-4.....................        200        705  .........  .........  .........  .........  ...........
Methyl mercaptan..........................  74-93-1......................        0.5          1  .........  .........  .........  .........  ...........
Methyl methacrylate.......................  80-62-6......................        100        410  .........  .........  .........  .........  ...........
Methyl parathion..........................  298-00-0.....................  .........        0.2  .........  .........  .........  .........           X
Methyl propyl ketone; see 2-Pentanone.....  107-87-9.
Methyl silicate...........................  681-84-5.....................          1          6  .........  .........  .........  .........  ...........
alpha-Methyl styrene......................  98-83-9......................         50        240        100        485  .........  .........  ...........
Methylene bisphenyl isocyanate (MDI)......  101-68-8.....................  .........  .........  .........  .........       0.02        0.2  ...........
Metribuzin................................  21087-64-9...................  .........          5  .........  .........  .........  .........  ...........
Mica; see Silicates.......................  N/A.
Molybdenum (as Mo)........................  7439-98-7.
                                            Soluble compounds............  .........          5  .........  .........  .........  .........  ...........
                                            Insoluble compounds total      .........         10  .........  .........  .........  .........  ...........
                                             dust.
                                            Insoluble compounds..........  .........          5  .........  .........  .........  .........  ...........
                                            Respirable fraction..........
Monocrotophos (Azodrin)...................  6923-22-4....................  .........       0.25  .........  .........  .........  .........  ...........
Monomethyl aniline........................  100-61-8.....................        0.5          2  .........  .........  .........  .........           X
Morpholine................................  110-91-8.....................         20         70         30        105  .........  .........           X
Naphtha (Coal tar)........................  8030-30-6....................        100        400  .........  .........  .........  .........  ...........
Naphthalene...............................  91-20-3......................         10         50         15         75  .........  .........  ...........
alpha-Naphthylamine; see 1910.1004........  134-32-7.
beta-Naphthylamine; see 1910.1009.........  91-59-8.
Nickel carbonyl (as Ni)...................  13463-39-3...................      0.001      0.007  .........  .........  .........  .........  ...........
Nickel, metal and insoluble compounds (as   7440-02-0....................  .........          1  .........  .........  .........  .........  ...........
 Ni).
Nickel, soluble compounds (as Ni).........  7440-02-0....................  .........        0.1  .........  .........  .........  .........  ...........
Nicotine..................................  54-11-5......................  .........        0.5  .........  .........  .........  .........           X
Nitric acid...............................  7697-37-2....................          2          5          4         10  .........  .........  ...........
Nitric oxide..............................  10102-43-9...................         25         30  .........  .........  .........  .........  ...........
p-Nitroaniline............................  100-01-6.....................  .........          3  .........  .........  .........  .........           X
Nitrobenzene..............................  98-95-3......................          1          5  .........  .........  .........  .........           X
p-Nitrochloro-benzene.....................  100-00-5.....................  .........          1  .........  .........  .........  .........           X
4-Nitrodiphenyl; see 1910.1003............  92-93-3.
Nitroethane...............................  79-24-3......................        100        310  .........  .........  .........  .........  ...........
Nitrogen dioxide..........................  10102-44-0...................  .........  .........          1        1.8  .........  .........  ...........
Nitrogen trifluoride......................  7783-54-2....................         10         29  .........  .........  .........  .........  ...........
Nitroglycerin.............................  55-63-0......................  .........  .........  .........       0.11  .........  .........           X
Nitromethane..............................  75-52-5......................        100        250  .........  .........  .........  .........  ...........
1-Nitropropane............................  108-03-2.....................         25         90  .........  .........  .........  .........  ...........
2-Nitropropane............................  79-46-9......................         10         35  .........  .........  .........  .........  ...........
N-Nitrosodimethyl-amine; see 1910.1016....  62-75-9.
Nitrotoluene..............................  o-isomer 88-72-2.............          2         11  .........  .........  .........  .........           X
                                            m-isomer 99-08-1.............
                                            p-isomer 99-99-0.............
Nitrotrichloro-methane; see Chloropicrin..  76-06-2.
Nonane....................................  111-84-2.....................        200       1050  .........  .........  .........  .........  ...........
Octachloro-naphthalene....................  2234-13-1....................  .........        0.1  .........        0.3  .........  .........           X
Octane....................................  111-65-9.....................        300       1450        375       1800  .........  .........  ...........
Oil mist, mineral.........................  8012-95-1....................  .........          5  .........  .........  .........  .........  ...........
Osmium tetroxide (as Os)..................  20816-12-0...................     0.0002      0.002     0.0006      0.006  .........  .........  ...........
Oxalic acid...............................  144-62-7.....................  .........          1  .........          2  .........  .........  ...........
Oxygen difluoride.........................  7783-41-7....................  .........  .........  .........  .........       0.05        0.1  ...........
Ozone.....................................  10028-15-6...................        0.1        0.2        0.3        0.6  .........  .........  ...........
Paraffin wax fume.........................  8002-74-2....................  .........          2  .........  .........  .........  .........  ...........
Paraquat, respirable dust.................  4685-14-7....................  .........        0.1  .........  .........  .........  .........           X
Parathion.................................  56-38-2......................  .........        0.1  .........  .........  .........  .........           X
Particulates not otherwise regulated......  N/A.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Pentaborane...............................  19624-22-7...................      0.005       0.01      0.015       0.03  .........  .........  ...........
Pentachloro-naphthalene...................  1321-64-8....................  .........        0.5  .........  .........  .........  .........           X
Pentachloro-phenol........................  87-86-5......................  .........        0.5  .........  .........  .........  .........           X
Pentaerythritol...........................  115-77-5.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Pentane...................................  109-66-0.....................        600       1800        750       2250  .........  .........  ...........
2-Pentanone (Methyl propyl ketone)........  107-87-9.....................        200        700        250        875  .........  .........  ...........
Perchloro-ethylene (Tetrachloro-ethylene).  127-18-4.....................         25        170  .........  .........  .........  .........  ...........
Perchloromethyl mercaptan.................  594-42-3.....................        0.1        0.8  .........  .........  .........  .........  ...........
Perchloryl fluoride.......................  7616-94-6....................          3         14          6         28  .........  .........  ...........
Perlite.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Petroleum distillates (Naphtha)...........  8002-05-9....................        400       1600  .........  .........  .........  .........  ...........
Phenol....................................  108-95-2.....................          5         19  .........  .........  .........  .........           X
Phenothiazine.............................  92-84-2......................  .........          5  .........  .........  .........  .........           X
p-Phenylene diamine.......................  106-50-3.....................  .........        0.1  .........  .........  .........  .........           X
Phenyl ether, vapor.......................  101-84-8.....................          1          7  .........  .........  .........  .........  ...........
Phenyl ether-biphenyl mixture, vapor......  N/A..........................          1          7  .........  .........  .........  .........  ...........
Phenylethylene; see Styrene...............  100-42-5.
Phenyl glycidyl ether (PGE)...............  122-60-1.....................          1          6  .........  .........  .........  .........  ...........
Phenylhydrazine...........................  100-63-0.....................          5         20         10         45  .........  .........           X
Phenyl mercaptan..........................  108-98-5.....................        0.5          2  .........  .........  .........  .........  ...........
Phenylphosphine...........................  638-21-1.....................  .........  .........  .........  .........       0.05       0.25  ...........
Phorate...................................  298-02-2.....................  .........       0.05  .........        0.2  .........  .........           X
Phosdrin (Mevinphos[supreg])..............  7786-34-7....................       0.01        0.1       0.03        0.3  .........  .........           X
Phosgene (Carbonyl chloride)..............  75-44-5......................        0.1        0.4  .........  .........  .........  .........  ...........
Phosphine.................................  7803-51-2....................        0.3        0.4          1          1  .........  .........  ...........
Phosphoric acid...........................  7664-38-2....................  .........          1  .........          3  .........  .........  ...........
Phosphorus (yellow).......................  7723-14-0....................  .........        0.1  .........  .........  .........  .........  ...........
Phosphorus oxychloride....................  10025-87-3...................        0.1        0.6  .........  .........  .........  .........  ...........
Phosphorus pentachloride..................  10026-13-8...................  .........          1  .........  .........  .........  .........  ...........
Phosphorus pentasulfide...................  1314-80-3....................  .........          1  .........          3  .........  .........  ...........
Phosphorus trichloride....................  7719-12-2....................        0.2        1.5        0.5          3  .........  .........  ...........
Phthalic anhydride........................  85-44-9......................          1          6  .........  .........  .........  .........  ...........
m-Phthalodinitrile........................  626-17-5.....................  .........          5  .........  .........  .........  .........  ...........
Picloram..................................  1918-02-1.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Picric acid...............................  88-89-1......................  .........        0.1  .........  .........  .........  .........           X
Piperazine dihydrochloride................  142-64-3.....................  .........          5  .........  .........  .........  .........  ...........
Pindone (2-Pivalyl- 1,3-indandione).......  83-26-1......................  .........        0.1  .........  .........  .........  .........  ...........
Plaster of Paris..........................  7778-18-9.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Platinum (as Pt)..........................  7440-06-4.
                                            Metal........................  .........          1  .........  .........  .........  .........  ...........
                                            Soluble salts................  .........      0.002  .........  .........  .........  .........  ...........
Portland cement...........................  65997-15-1.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Potassium hydroxide.......................  1310-58-3....................  .........  .........  .........  .........  .........          2  ...........
Propane...................................  74-98-6......................       1000       1800  .........  .........  .........  .........  ...........
Propargyl alcohol.........................  107-19-7.....................          1          2  .........  .........  .........  .........           X
beta-Propriolactone; see 1910.1013........  57-57-8.
Propionic acid............................  79-09-4......................         10         30  .........  .........  .........  .........  ...........
Propoxur (Baygon).........................  114-26-1.....................  .........        0.5  .........  .........  .........  .........  ...........
n-Propyl acetate..........................  109-60-4.....................        200        840        250       1050  .........  .........  ...........
n-Propyl alcohol..........................  71-23-8......................        200        500        250        625  .........  .........  ...........
n-Propyl nitrate..........................  627-13-4.....................         25        105         40        170  .........  .........  ...........
Propylene dichloride......................  78-87-5......................         75        350        110        510  .........  .........  ...........
Propylene glycol dinitrate................  6423-43-4....................       0.05        0.3  .........  .........  .........  .........  ...........
Propylene glycol monomethyl ether.........  107-98-2.....................        100        360        150        540  .........  .........  ...........
Propylene imine...........................  75-55-8......................          2          5  .........  .........  .........  .........           X
Propylene oxide...........................  75-56-9......................         20         50  .........  .........  .........  .........  ...........
Propyne; see Methyl acetylene.............  74-99-7.
Pyrethrum.................................  8003-34-7....................  .........          5  .........  .........  .........  .........  ...........
Pyridine..................................  110-86-1.....................          5         15  .........  .........  .........  .........  ...........
Quinone...................................  106-51-4.....................        0.1        0.4  .........  .........  .........  .........  ...........
Resorcinol................................  108-46-3.....................         10         45         20         90  .........  .........  ...........
Rhodium (as Rh), metal fume and insoluble   7440-16-6....................  .........        0.1  .........  .........  .........  .........  ...........
 compounds.
Rhodium (as Rh), soluble compounds........  7440-16-6....................  .........      0.001  .........  .........  .........  .........  ...........
Ronnel....................................  299-84-3.....................  .........         10  .........  .........  .........  .........  ...........
Rosin core solder pyrolysis products, as    .............................  .........        0.1  .........  .........  .........  .........  ...........
 formaldehyde.
Rotenone..................................  83-79-4......................  .........          5  .........  .........  .........  .........  ...........
Rouge.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Selenium compounds (as Se)................  7782-49-2....................  .........        0.2  .........  .........  .........  .........  ...........
Selenium hexafluoride (as Se).............  7783-79-1....................       0.05        0.4  .........  .........  .........  .........  ...........
Silica, amorphous, precipitated and gel...  .............................  .........          6  .........  .........  .........  .........  ...........
Silica, amorphous, diatomaceous earth,      68855-54-9...................  .........          6  .........  .........  .........  .........  ...........
 containing less than 1% crystalline
 silica.
Silica, crystalline cristobalite            14464-46-1...................  .........       0.05  .........  .........  .........  .........  ...........
 respirable dust.
Silica, crystalline, quartz, respirable     14808-60-7...................  .........        0.1  .........  .........  .........  .........  ...........
 dust.
Silica, crystalline tripoli (as quartz),    1317-95-9....................  .........        0.1  .........  .........  .........  .........  ...........
 respirable dust.
Silica, crystalline tridymite respirable    15468-32-3...................  .........       0.05  .........  .........  .........  .........  ...........
 dust.
Silica, fused, respirable dust............  60676-86-0...................  .........        0.1  .........  .........  .........  .........  ...........
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                       Silicates (less than 1% crystalline silica)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mica (respirable dust)....................  12001-26-2...................  .........          3  .........  .........  .........  .........  ...........
Soapstone, total dust.....................  .............................  .........          6  .........  .........  .........  .........  ...........
Soapstone, respirable dust................  .............................  .........          3  .........  .........  .........  .........  ...........
Talc (containing asbestos): Use asbestos
 limit; see 1910.1001.
Talc (containing no asbestos), respirable   14807-96-6...................  .........          2  .........  .........  .........  .........  ...........
 dust.
Tremolite; asbestiform--see 1910.1001; non- .............................  .........  .........  .........  .........  .........  .........  ...........
 asbestiform--see 57 FR 24310, June 8,
 1992.
Silicon...................................  7440-21-3.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Silicon carbide...........................  409-21-2.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Silicon tetrahydride......................  7803-62-5....................          5          7  .........  .........  .........  .........  ...........
Silver, metal and soluble compounds (as     7440-22-4....................  .........       0.01  .........  .........  .........  .........  ...........
 Ag).
Soapstone; see Silicates
Sodium azide..............................  26628-22-8.
                                            (as HN3).....................  .........  .........  .........  .........        0.1  .........           X
                                            (as NaN3 )...................  .........  .........  .........  .........  .........        0.3           X
Sodium bisulfite..........................  7631-90-5....................  .........          5  .........  .........  .........  .........  ...........
Sodium fluoroacetate......................  62-74-8......................  .........       0.05  .........       0.15  .........  .........           X
Sodium hydroxide..........................  1310-73-2....................  .........  .........  .........  .........  .........          2  ...........
Sodium metabisulfite......................  7681-57-4....................  .........          5  .........  .........  .........  .........  ...........
Starch....................................  9005-25-8.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Stibine...................................  7803-52-3....................        0.1        0.5  .........  .........  .........  .........  ...........
Stoddard solvent..........................  8052-41-3....................        100        525  .........  .........  .........  .........  ...........
Strychnine................................  57-24-9......................  .........       0.15  .........  .........  .........  .........  ...........
Styrene...................................  100-42-5.....................         50        215        100        425  .........  .........  ...........
Subtilisins (Proteolytic enzymes).........  1395-21-7....................  .........  .........  .........  .........  .........   0. 00006  ...........
Sucrose...................................  57-50-1.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Sulfur dioxide............................  7446-09-5....................          2          5          5         13  .........  .........  ...........
Sulfur hexafluoride.......................  2551-62-4....................       1000       6000  .........  .........  .........  .........  ...........
Sulfuric acid.............................  7664-93-9....................  .........          1  .........  .........  .........  .........  ...........
Sulfur monochloride.......................  10025-67-9...................  .........  .........  .........  .........          1          6  ...........
Sulfur pentafluoride......................  5714-22-7....................  .........  .........  .........  .........       0.01        0.1  ...........
Sulfur tetrafluoride......................  7783-60-0....................  .........  .........  .........  .........        0.1        0.4  ...........
Sulfuryl fluoride.........................  2699-79-8....................          5         20         10         40  .........  .........  ...........
Sulprofos.................................  35400-43-2...................  .........          1  .........  .........  .........  .........  ...........
Systox[supreg]; see Demeton...............  8065-48-3.
2,4,5-T...................................  93-76-5......................  .........         10  .........  .........  .........  .........  ...........
Talc; see Silicates.
Tantalum, metal and oxide dust............  7440-25-7....................  .........          5  .........  .........  .........  .........  ...........
TEDP (Sulfotep)...........................  3689-24-5....................  .........        0.2  .........  .........  .........  .........           X
Tellurium and compounds (as Te)...........  13494-80-9...................  .........        0.1  .........  .........  .........  .........  ...........
Tellurium hexafluoride (as Te)............  7783-80-4....................       0.02        0.2  .........  .........  .........  .........  ...........
Temephos..................................  3383-96-8.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
TEPP......................................  107-49-3.....................  .........       0.05  .........  .........  .........  .........           X
Terphenyls................................  26140-60-3...................  .........  .........  .........  .........        0.5          5  ...........
1,1,1,2-Tetrachloro-2,2-difluoroethane....  76-11-9......................        500       4170  .........  .........  .........  .........  ...........
1,1,2,2-Tetrachloro 1,2-difluoroethane....  76-12-0......................        500       4170  .........  .........  .........  .........  ...........
1,1,2,2-Tetrachloro-ethane................  79-34-5......................          1          7  .........  .........  .........  .........           X
Tetrachoro-ethylene; see Perchloro-         127-18-4.
 ethylene.
Tetrachloro-methane; see Carbon             56-23-5.
 tetrachloride.
Tetrachloro-naphthalene...................  1335-88-2....................  .........          2  .........  .........  .........  .........           X
Tetraethyl lead (as Pb)...................  78-00-2......................  .........      0.075  .........  .........  .........  .........           X
Tetrahydrofuran...........................  109-99-9.....................        200        590        250        735  .........  .........  ...........
Tetramethyl lead (as Pb)..................  75-74-1......................  .........      0.075  .........  .........  .........  .........           X
Tetramethyl succinonitrile................  3333-52-6....................        0.5          3  .........  .........  .........  .........           X
Tetranitro-methane........................  509-14-8.....................          1          8  .........  .........  .........  .........  ...........
Tetrasodium pyrophosphate.................  7722-88-5....................  .........          5  .........  .........  .........  .........  ...........
Tetryl (2,4,6-Trinitro-phenyl-methyl-       479-45-8.....................  .........        0.1  .........  .........  .........  .........           X
 nitramine).
Thallium, soluble compounds (as Tl).......  7440-28-0....................  .........        0.1  .........  .........  .........  .........           X
4,4'-Thiobis (6-tert-Butyl-m-cresol)......  96-69-5.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Thioglycolic acid.........................  68-11-1......................          1          4  .........  .........  .........  .........           X
Thionyl chloride..........................  7719-09-7....................  .........  .........  .........  .........          1          5  ...........
Thiram....................................  137-26-8.....................  .........          5  .........  .........  .........  .........  ...........
Tin, inorganic compounds (except oxides)    7440-31-5....................  .........          2  .........  .........  .........  .........  ...........
 (as Sn).
Tin, organic compounds (as Sn)............  7440-31-5....................  .........        0.1  .........  .........  .........  .........           X
Tin oxide (as Sn).........................  7440-31-5....................  .........          2  .........  .........  .........  .........  ...........
Titanium dioxide..........................  13463-67-7.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Toluene...................................  108-88-3.....................        100        375        150        560  .........  .........  ...........
Toluene-2,4-diisocyanate (TDI)............  584-84-9.....................      0.005       0.04       0.02       0.15  .........  .........  ...........
m-Toluidine...............................  108-44-1.....................          2          9  .........  .........  .........  .........           X
o-Toluidine...............................  95-53-4......................          5         22  .........  .........  .........  .........           X
p-Toluidine...............................  106-49-0.....................          2          9  .........  .........  .........  .........           X
Toxaphene; see Chlorinated camphene.......  8001-35-2.
Tremolite; see Silicates..................  N/A.
Tributyl phosphate........................  126-73-8.....................        0.2        2.5  .........  .........  .........  .........  ...........
Trichloroacetic acid......................  76-03-9......................          1          7  .........  .........  .........  .........  ...........
1,2,4-Trichloro-benzene...................  120-82-1.....................  .........  .........  .........  .........          5         40  ...........
1,1,1-Trichloroethane; see Methyl           71-55-6.
 chloroform.
1,1,2-Trichloroethane.....................  79-00-5......................         10         45  .........  .........  .........  .........           X
Trichloro-ethylene........................  79-01-6......................         50        270        200       1080  .........  .........  ...........
Trichloro-methane; see Chloroform.........  67-66-3.
Trichloro-naphthalene.....................  1321-65-9....................  .........          5  .........  .........  .........  .........           X
1,2,3-Trichloropropane....................  96-18-4......................         10         60  .........  .........  .........  .........  ...........
1,1,2-Trichloro-1,2,2-trifluoroethane.....  76-13-1......................       1000       7600       1250       9500  .........  .........  ...........
Triethylamine.............................  121-44-8.....................         10         40         15         60  .........  .........  ...........
Trifluorobromo-methane....................  75-63-8......................       1000       6100  .........  .........  .........  .........  ...........
Trimellitic anhydride.....................  552-30-7.....................      0.005       0.04  .........  .........  .........  .........  ...........
Trimethylamine............................  75-50-3......................         10         24         15         36  .........  .........  ...........
Trimethyl benzene.........................  25551-13-7...................         25        125  .........  .........  .........  .........  ...........
Trimethyl phosphite.......................  121-45-9.....................          2         10  .........  .........  .........  .........  ...........
2,4,6-Trinitrophenyl; see Picric acid.....  88-89-1.
2,4,6-Trinitrophenylmethyl nitramine; see   479-45-8.
 Tetryl.
2,4,6-Trinitrotoluene (TNT)...............  118-96-1.....................  .........        0.5  .........  .........  .........  .........           X
Triorthocresyl phosphate..................  78-30-8......................  .........        0.1  .........  .........  .........  .........           X
Triphenyl amine...........................  603-34-9.....................  .........          5  .........  .........  .........  .........  ...........
Triphenyl phosphate.......................  115-86-6.....................  .........          3  .........  .........  .........  .........  ...........
Tungsten (as W)...........................  7440-33-7.
                                            Insoluble compounds..........  .........          5  .........         10  .........  .........  ...........
                                            Soluble compounds............  .........          1  .........          3  .........  .........  ...........
Turpentine................................  8006-64-2....................        100        560  .........  .........  .........  .........  ...........
Uranium (as U)............................  7440-61-1.
                                            Soluble compounds............  .........       0.05  .........  .........  .........  .........  ...........
                                            Insoluble compounds..........  .........        0.2  .........        0.6  .........  .........  ...........
n-Valeraldehyde...........................  110-62-3.....................         50        175  .........  .........  .........  .........  ...........
Vanadium..................................  1314-62-1.
                                            Respirable Dust as V205......  .........       0.05  .........  .........  .........  .........  ...........
                                            Fume (as V205)...............  .........       0.05  .........  .........  .........  .........  ...........
Vegetable Oil Mist........................  N/A.
                                            Total dust...................  .........         15  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Vinyl acetate.............................  108-05-4.....................         10         30         20         60  .........  .........  ...........
Vinyl benzene; see Styrene................  100-42-5.
Vinyl bromide.............................  593-60-2.....................          5         20  .........  .........  .........  .........  ...........
Vinyl chloride; see 1910.1017.............  75-01-4.
Vinyl cyanide; see Acrylonitrile..........  107-13-1.
Vinyl cyclohexene dioxide.................  106-87-6.....................         10         60  .........  .........  .........  .........           X
Vinylidene chloride (1,1-Dichloro-          75-35-4......................          1          4  .........  .........  .........  .........  ...........
 ethylene).
Vinyl toluene.............................  25013-15-4...................        100        480  .........  .........  .........  .........  ...........
VM & P Naphtha............................  8032-32-4....................        300       1350        400       1800  .........  .........  ...........
Warfarin..................................  81-81-2......................  .........        0.1  .........  .........  .........  .........  ...........
Welding fumes (total particulate)*........  N/A..........................  .........          5  .........  .........  .........  .........  ...........
Wood dust, all soft and hard woods, except  N/A..........................  .........          5  .........         10  .........  .........  ...........
 Western red cedar.
Wood dust, western red cedar..............  N/A..........................  .........        2.5  .........  .........  .........  .........  ...........
Xylenes (o-, m-, p-isomers)...............  1330-20-7....................        100        435        150        655  .........  .........  ...........
m-Xylene alpha, alpha' diamine............  1477-55-0....................  .........  .........  .........  .........  .........        0.1           X
Xylidine..................................  1300-73-8....................          2         10  .........  .........  .........  .........           X
Yttrium...................................  7440-65-5....................  .........          1  .........  .........  .........  .........  ...........
Zinc chloride fume........................  7646-85-7....................  .........          1  .........          2  .........  .........  ...........
Zinc chromate (as CrO3); see 910.1026. See  Varies with compound.
 Table Z-2 for the exposure limit for any
 operations or sectors where the exposure
 limit in 1910.1026 is stayed or are
 otherwise not in effect.
Zinc oxide fume...........................  1314-13-2....................  .........          5  .........         10  .........  .........  ...........
Zinc oxide................................  1314-13-2.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Zinc stearate.............................  557-05-1.
                                            Total dust...................  .........         10  .........  .........  .........  .........  ...........
                                            Respirable fraction..........  .........          5  .........  .........  .........  .........  ...........
Zirconium compounds (as Zr)...............  7440-67-7....................  .........          5  .........         10  .........  .........  ...........
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\(30 minutes).

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Ex. #93: OSHA Cancer Policy, 29 CFR 1990.111(k) (2011).
Ex. #94: OSHA Cancer Policy, 29 CFR 1990.132(b)(6) (2011).
Ex. #95: OSHA Cancer Policy, 29 CFR 1990.146(k) (2011).
Ex. #96: Respiratory Protection, 29 CFR 1910.134(a) (2011).
Ex. #97: Air Contaminants, 29 CFR 1910.1000(e) (2011).
Ex. #98: Occupational Exposure to Methylene Chloride, 62 FR 1494
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Ex. #99: Occupational Exposure to Hexavalent Chromium, 71 FR 10099
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Ex. #100: Occupational Safety and Health Administration. (1996).
Final economic and regulatory flexibility analysis for OSHA's
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Ex. #102: Occupational Safety and Health Administration. (1987).
Regulatory impact and regulatory flexibility analysis of the
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Ex. #103: Occupational Safety and Health Administration. (1984).
Regulatory impact and regulatory flexibility analysis of the final
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Regulatory Review of 29 CFR 1910.1052: Methylene chloride.
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Ex. #109: Council Directive on the Protection of the Health and
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Ex. #110: Directive of the European Parliament and of the Council on
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Ex. #114: German Federal Institute for Occupational Safety and
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Ex. #125: Hazard Communication, 77 FR 17574 (Mar. 26, 2012).
Ex. #126: National Safety Council, Fundamentals of Industrial
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Ex. #142: National Consensus Standards and Established Federal
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Ex. #143: Longshore and Harbor Workers' Compensation, 33 U.S.C. 901-
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Ex. #149: 1989 PELs Table. 54 FR 2332, 2923-2959.

[FR Doc. 2014-24009 Filed 10-9-14; 8:45 am]
BILLING CODE 4510-26-P


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