Man-made mineral fiber exposure limits and health risks

NOTICE: This is an OSHA Archive Document, and may no longer represent OSHA Policy. It is presented here as historical content, for research and review purposes only.

Aug 2, 1985

J. Bognar, Manager
Environmental Technology
N.Z. Forest Products Limited
[Recipient address omitted]

Dear Mr. Bognar:

Thank you for your letter of July 12, to former Assistant Secretary Robert Rowland, concerning the occupational exposure standard on man-made mineral fiber (MMMF). Your letter has been referred to this office for response.

Following are answers to your seven questions:

1. What is the current TLV for MMMF in your country?

The current Threshold Limit Value (TLV) as adopted by the American Conference of Governmental Industrial Hygienists (ACGIH) for MMMF is 10 milligrams per cubic meter of air (10 mg/m3). However, TLVs are not enforced by legislation. The Occupational Safety and Health Administration (OSHA) does regulate MMMF as an inert or nuisance dust. The OSHA permissible exposure limit (PEL) for mineral fibers is 15 mg/m3.

2. Are the current TLVs specified by legislation?

OSHA does not enforce TLVs for MMMF. However, OSHA does enforce the PEL for MMMF.

3. Are there any changes being considered to TLV? 4. What are the details of the proposed changes? 5. What are the main reasons for the proposed changes? 6. When will the new TLV be likely to be implemented?

In reply to each of the above, there are no proposed changes to the current TLV or to the OSHA PEL for MMMF.

7. Has the risk associated with the use of MMMF been quantified?

It has been suggested that the inhalation of very fine mineral fibers such as asbestos or glass fiber could increase the incidence of cancer because the particle size of these fibers are essentially respirable. However, the particle size of the majority of mineral fibers products such as glass fibers for industrial use and consumer goods such as appliance and building insulation materials, furnace filters, and reinforced glass fiber plastics are generally non-respirable. The health risk associated with prolonged exposure for these fibers are significantly lower than those for asbestos fibers.

The National Institute for Occupational Safety and Health (NIOSH) is the Federal agency which conducts research in occupational safety and health for OSHA. For additional information on the health risk associated with the use of MMMF, you may contact them at the following address:

Mr. Richard Lemen, Director
Division of Standards Development and Technology Transfer
National Insitutute for Occupational Safety and Health
4676 Columbia Parkway
Cincinnati, Ohio 45226

Sincerely,
James J. Concannon
Acting Director
Directorate of Technical Support

[Requester letter reproduced on OSHA page; omitted here.]