October 11, 1995

Mr. Dave Koch
Senior Technical Service Specialist
Willson Safety Products
Post Office Box 622
Reading, Pennsylvania 19603-0622

Dear Mr. Koch:

This is in response to your letter to Mr. Jim Johnson in the Occupational Safety and Health Administration's (OSHA) Philadelphia Regional Office dated August 30. Your letter was forwarded to the OSHA National Office for response. The letter requested a clarification on OSHA's policy regarding Immediately Dangerous to Life and Health (IDLH) since National Institute for Occupational Safety and Health (NIOSH) has lowered several IDLH levels in their (1994) NIOSH Pocket Guide to Chemical Hazards.

The IDLH guidelines are set by NIOSH on the best available scientific evidence, but since NIOSH is not a regulatory agency and the guidelines have not been set through a regulatory procedure, they are not legal standards. Actual IDLH numeric limits or levels are not specified in OSHA standards. If the company involved has scientific evidence which can rebut the NIOSH recommended IDLH and points to a less restrictive limit, then it is up to the OSHA to weigh the evidence and make a determination on a case by case basis. If the employer does not have evidence which can plausibly rebut the NIOSH recommended IDLH, then the NIOSH limit certainly prevails.

An employer would use the IDLH limit set by NIOSH in determining appropriate respirator selection to comply with the OSHA standards. In many OSHA substance specific standards, however, there are tables which list the minimum, prescriptive requirements for respiratory protection for the substance at various concentrations including unknown concentrations. Those respirator requirements take precedence.

Your interest in occupational safety and health is appreciated. If we can be of further assistance please feel free to contact OSHA's Office of Compliance Assistance at (202) 219-8036.

Sincerely,



John B. Miles Jr., Director
Directorate of Compliance Programs



September 13, 1995

Office of Health Compliance Assistance
U.S. Department of Labor
OSHA
200 Constitution Ave., NW
Washington, DC 20210

Dear Sir/Madam:

This letter is a follow-up to a letter you have received from Regional Administrator Linda R. Anku concerning changes to the immediately dangerous to life or health (IDLH) levels for various regulated compounds, such as but not limited to chlorine and chlorine dioxide.

We had previously asked Regional OSHA as to what IDLH levels are enforced by the Agency. NIOSH has changed various IDLH levels in its current Pocket Guide to Chemical Hazards and, since these levels are used in determining the correct respirator usage, it is of utmost importance that we receive a fastidious reply.

As a leader in the manufacture of personal protective equipment, Willson Safety Products has an obligation to relay correct information to the field so that the user of our PPE can be ensured he/she is using it correctly and in accordance with both NIOSH and OSHA Regulations.

Regards,



Dave Koch
Senior Technical Service Specialist



September 6, 1995

Dave Koch
Senior Technical Service Specialist
Willson Safety Products
P.O. Box 622
Reading, PA 19603-0622

Dear Mr. Koch:

This is in reply to your letter, dated August 30, 1995, concerning the IDLH level used by OSHA in enforcing prohibitions for usage of respirators in IDLH atmospheres. You note in your letter that NIOSH has lowered what they consider to be the IDLH level for chlorine.

Due to the potential national impact of the response, your letter has been referred to our national office for review. You may contact OSHA's Office of Health Compliance Assistance at (202) 219-8036 if you have any questions concerning your request.

Sincerely,



LINDA R. ANKU
Regional Administrator



August 30, 1995

Mr. Jim Johnson
Regional Industrial Hygienist
Occupational Safety and Health
Administration
Room 2100
3535 Market St.
Philadelphia, PA 19104

Fax: (215)596-4872

Dear Mr. Johnson:

It has come to our attention that various IDLH levels have been lowered in the latest (1994) NIOSH Pocket Guide to Chemical Hazards. For instance, the IDLH level for chlorine has been changed from 25 ppm to 10 ppm. What NIOSH IDLH level does OSHA use and enforce?

Willson Safety Products receives numerous inquiries about selecting and using the correct respiratory protection device for specific contaminants and/or contaminant concentrations. In order to alleviate any confusion regarding these levels, Willson Safety Products would greatly appreciate OSHA's policy and stance on this issue.

Thank you in advance for your time and consideration on this matter.

Sincerely yours,



Dave Koch
Senior Technical Service Specialist



September 14, 1995

Dave Koch
Senior Technical Service Specialist
Willson
PO Box 622
Reading, PA 19603-0622

Dear Mr. Dave Koch:

This is in response to your letter to Mr. Jim Johnson dated August 30, 1995. Your letter was forwarded to the OSHA National Office for response. The letter requested a clarification on OSHA's policy regarding IDLH since NIOSH has lowered several IDLH levels in their (1994) NIOSH Pocket Guide to Chemical Hazards.

IDLH actual numeric limits or levels are not specified in OSHA standards. IDLH limits are specified by NIOSH. To comply with the OSHA standards, an employer would use the IDLH limit set by NIOSH in determining appropriate respirator selection.

In many OSHA substance specific standards, there is a Table 1 Minimum Requirements for Respiratory Protection, which specifies a limit or unknown concentration. OSHA has not identified this limit as IDLH. However the substance specific standards do have a requirement that a NIOSH or MSHA approved respirator be selected. In a potential IDLH situation, the NIOSH IDLH limit shall be the deciding factor for respirator selection.

Your interest in occupational safety and health is appreciated. If we can be of further assistance please call.

Sincerely,



John B. Miles Jr., Director
Directorate of Compliance Programs