Workplace Exposure To Asbestos: Review And Recommendations

Our plain-English summary of Workplace Exposure To Asbestos: Review And Recommendations, by Niosh (1980).

The study

• Author: Niosh
• Published: Washington, Dc: Niosh, Dhhs Publication No. 81-103, April (1980)
• Type of article: Government report
• Our copy: from Johns-Manville's own medical library, J-M no. 004616.

In plain English

This 1980 publication is a review with recommendations, not a new study. A NIOSH/OSHA Asbestos Work Group, formed in fall 1979, reviewed the science on asbestos-related disease and the OSHA standard of 2,000,000 fibers longer than 5 micrometers per cubic meter. The committee concluded that animal studies showed all commercial forms of asbestos produce pulmonary fibrosis, mesothelioma and lung neoplasms. It also concluded that human occupational exposure to all commercial fiber types had been associated with high rates of asbestosis, lung cancer and mesothelioma. It found no scientific basis for regulating fiber types differently and no evidence of a threshold or "safe" level. It recommended a single standard far below the current one. It said the lowest detectable level should be a significant consideration in setting the limit; that level was then 100,000 fibers longer than 5 micrometers per cubic meter, averaged over an 8-hour workday. It also recommended baseline medical examinations. It judged that the combined effect of smoking and asbestos on lung cancer appeared multiplicative. The committee stated that limited data prevented describing an exact dose-response relationship. It also stated that even below 100,000 fibers there was no basis to conclude all asbestos-related cancers would be prevented.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Review of scientific literature with regulatory recommendations, by a joint NIOSH/OSHA committee (Asbestos Work Group)
• Who was studied: Published scientific information on asbestos-related disease in animals and humans, including literature since the 1976 NIOSH Criteria Document and the 1977 IARC review. The committee was formed in fall 1979 and the report is dated April 1980.
• Exposure: Workplace asbestos exposure, defined by the committee as chrysotile, crocidolite, and fibrous cummingtonite-grunerite including amosite, fibrous tremolite, fibrous actinolite and fibrous anthophyllite. The committee assessed the then-current OSHA standard of 2,000,000 fibers longer than 5 micrometers per cubic meter.
• Main results:
  • The committee concluded from animal studies that all commercial forms of asbestos produce pulmonary fibrosis, mesothelioma and lung neoplasms.
  • The committee concluded that human occupational exposure to all commercial asbestos fiber types, alone and in combination, has been associated with high rates of asbestosis, lung cancer and mesothelioma.
  • The committee found no scientific basis for differentiating fiber types and recommended one standard for all asbestos fiber types.
  • The committee found that available human data provided no evidence for a threshold or a 'safe' level of asbestos exposure.
  • The committee concluded that the occupational standard should be set far below the current 2,000,000-fiber standard.
  • The committee said the lowest detectable exposure level should be a significant consideration in setting a permissible exposure limit. It gave that level as 100,000 fibers longer than 5 micrometers per cubic meter, averaged over an 8-hour workday.
  • The committee concluded that membrane filter-phase contrast microscopy was the only method reasonably usable for routine monitoring and compliance sampling.
  • Drawing on the reviewed studies, the committee concluded that the combined effect of asbestos exposure and smoking on lung cancer appears multiplicative rather than additive.
  • The committee recommended baseline medical examinations for all workers potentially exposed or previously exposed to asbestos.
• The authors' conclusion: The authors concluded that where asbestos uses cannot be eliminated or replaced with less toxic materials, worker exposure must be controlled to the maximum extent possible. They also concluded that even below 100,000 fibers there is no scientific basis for concluding that all asbestos-related cancers would be prevented.
• Limitations the authors state:
  • The committee stated that limited current data prevent constructing any one curve describing the exact dose-response relationship.
  • The committee stated that no adequate epidemiological information existed on workers exposed below the current standard and followed long enough to see long-latency effects.
  • The committee noted that light microscopy cannot detect short asbestos fibers to which workers are exposed.
  • The committee stated that available information was insufficient to determine the role of specific fiber types in excesses of cancer at other sites.

Topics

Medical terms in this study, explained in our Lexicon: NIOSH, OSHA, Pulmonary Fibrosis, Mesothelioma, Neoplasm, Occupational Exposure, Lung Cancer, Dose-response relationship.

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