Aug 2, 1985

J. Bognar, Manager
Environmental Technology
N.Z. Forest Products Limited
Private Bag, Auckland
1 New Zealand

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




July 12, 1985

Mr. Robert A. Rowland
Assistant Secretary of Labor
Occupational Safety & Health Administration
Washington, DC 20210
UNITED STATES OF AMERICA

Dear Sir,

RE: MAN MADE MINERALL FIBRE (MMMF)

Although our main manufacturing activities are related to forest products (pulp, paper, lumber and wood-based panels) we are also manufacturing mineral fibre (rock wool from basalt rock).

The situation with regard to the manufacture and use of MMMF in New Zealand has, until recently, been relatively quiet. However, the repeated publicity given to asbestos has generated a sentiment that MMMF and related products may also be implicated and present, on a long term basis, a hazard to health.

In spite of the fact that there appears to be no conclusive evidence, some groups and their medical advisers are exerting pressure on the New Zealand regulatory authorities (Department of Health) to admit that MMMF is not only a nuisance dust, but it also represents a significant occupational health risk.

Because of these concerns, the Department of Health and the Occupational Health Advisory Committee of New Zealand are at present considering the occupational health aspects of manufacturing and using MMMF and there is currently a proposal to introduce more stringent and a dual threshold limit value (TLV) of:

1. 5 mg/m3 total dust and

2. 1 fibre/ml of air respirable fibre concentration.

It is proposed that the above TLV are to apply simultaneously.

As manufacturers of MMMF we are cencerned that these TLV values now proposed for MMMF are unduly stringent and in fact, are to be similar to those applicable to asbestos (except crocidolite), which would suggest and/or imply that the risk associated with the use of MMMF was also similar.

We believe that scientific evidence currently available does indicate that the risk (if any) associated with MMMF does not approach the hazards of asbestos.

This brings me to the main purpose of my letter which is to obtain up-to-date information on the occupational health related regulatory requirements in your country concerning the manufacture and use of MMMF.

More specifically, we would appreciate it if you could provide us information on the following:

(1) What are the current TLV for MMMF in your country?
(2) Are the current TLV specified by legislation?
(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 change?
(6) When will the new TLV be likely to be implemented?
(7) Has the risk associated with the use of MMMF been quantified?

Any other comment relevant to the occupational health aspects of MMMF would be appreciated.

Thank you for your co-operation.

Yours sincerely,



J. Bognar
Manager
ENVIRONMENTAL TECHNOLOGY
N.Z. Forest Products Limited
Private Bag, Auckland 1, N.Z.