Asbestos: scientific developments and implications for public policy

Our plain-English summary of Asbestos: scientific developments and implications for public policy, by B.T. Mossman, J. Bignon, M. Corn, et al (Science, 1990).

The study

• Authors: B.T. Mossman, J. Bignon, M. Corn, A. Seaton, J.B. Gee
• Journal: Science
• Published: 1990;247(4940):294-301
• Cited by: 486 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 000032).

Abstract

Asbestos is a commercial term for a group of fibrous minerals often associated with the development of pulmonary interstitial fibrosis (asbestosis), lung cancer, and malignant mesothelioma in occupationally exposed individuals. The pathogenicity of different forms of asbestos varies--long, thin amphibole fibers are most pathogenic, particularly in the induction of mesothelioma. Available data do not support the concept that low-level exposure to asbestos is a health hazard in buildings and schools. The concentration of asbestos fibers in air, type of asbestos, and size of fibers must be considered in evaluation of potential health risks.

In plain English

This 1990 review summarized published research on asbestos fiber types, related diseases, laboratory and animal studies, and airborne asbestos in U.S. schools and buildings, and discussed public policy. They cited proportional mortality from mesothelioma of approximately 6 to 8% in men working with mixtures containing crocidolite or amphibole, versus less than 1% in men working with chrysotile. In female cohorts the figures were 10.6% for amphibole exposure and 0.2% for chrysotile exposure. In rodent injection experiments, they noted, chrysotile was as carcinogenic as the amphiboles. Surveys put the mean airborne concentration in schools at 0.00024 fibers longer than 5 micrometers per cubic centimeter. Six published estimates of lifetime lung cancer and mesothelioma deaths, for students exposed at that mean for five school years from age 10, gave an annual rate of 0.005 to 0.093 deaths per million students, assuming a 75-year life expectancy. The authors concluded that available data do not support the concept that low-level exposure to asbestos is a health hazard in buildings and schools. They acknowledged that high-to-low dose extrapolation has never been confirmed empirically.

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 published epidemiologic, experimental and building air-sampling research, with discussion of U.S. public policy
• Who was studied: No new study population. The authors drew on published studies of asbestos workers, laboratory animals and cells, and air-sampling surveys of U.S. schools and public buildings (387 indoor and 48 outdoor samples in the public buildings study).
• Exposure: Asbestos fiber types: chrysotile (serpentine) and the amphiboles crocidolite, amosite, anthophyllite, actinolite and tremolite. Occupational exposure was compared with low-level airborne exposure in schools and buildings.
• Main results:
  • Cited data: mesothelioma accounted for approximately 6 to 8% of proportional mortality in men working with mixtures containing crocidolite or amphibole, compared with less than 1% in men working with chrysotile.
  • Cited data, female cohorts: proportional mortality from mesothelioma was 10.6% with amphibole exposure and 0.2% with chrysotile exposure.
  • Cited French lung-tissue study: numbers of amphibole fibers (crocidolite and amosite) were significantly higher in the lungs of mesothelioma patients.
  • Cited British cohort exposed since 1970 to chrysotile at no more than 0.5 to 1.0 fiber per cubic centimeter in friction-material manufacture: no excess deaths from lung cancer, other asbestos-related tumors, or chronic respiratory disease.
  • Cited animal studies: after injection into the pleura or peritoneum of rodents, chrysotile was as carcinogenic as the amphiboles.
  • Building surveys: the mean airborne concentration in schools was 0.00024 fibers per cubic centimeter of air (fibers longer than 5 micrometers). In the public buildings study, no asbestos fibers were detected in 83% of the 387 indoor samples.
  • According to the authors, building airborne levels were approximately 1/100 of the U.S. workplace permissible exposure of 0.2 fibers per cubic centimeter.
  • Six published risk estimates modeled lifetime deaths from lung cancer and mesothelioma among students exposed to 0.00024 fibers per cubic centimeter for five school years beginning at age 10. They gave an annual rate of 0.005 to 0.093 deaths per million students, assuming an average life expectancy of 75 years.
  • Cited French study of building occupants, still in progress: no mesotheliomas observed to date among approximately 15,000 permanent occupants.
• The authors' conclusion: The authors concluded that available data do not support the concept that low-level exposure to asbestos is a health hazard in buildings and schools. They also concluded that fiber concentration, fiber type and fiber size must be considered in evaluating risk.
• Limitations the authors state:
  • Extrapolating from high to low doses has never been confirmed empirically for asbestos.
  • Published risk estimates vary from study to study.
  • Animal inhalation studies at low-level exposures are too costly to carry out long term.
  • Death certificates may underestimate or overestimate the incidence of mesothelioma.
  • The French building-occupant survey was still in progress.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Chrysotile.

Medical terms in this study, explained in our Lexicon: Interstitial Fibrosis, Lung Cancer, Malignant Mesothelioma, Amphibole Group, Mesothelioma.

Related studies

• Asbestos in New York City public school buildings--public policy: is there a scientific basis? — R. Wilson, A.M. Langer, et al. (1994)
• Naturally occurring asbestos: a recurring public policy challenge — R.J. Lee, B.R. Strohmeier, et al. (2008)
• Asbestos-associated diseases. Science, public policy, and litigation — H. Weill (1983)
• The role of threshold limit values in U.S. air pollution policy — J.C. Robinson, D.G. Paxman (1992)
• Scientific controversy and asbestos: making disease invisible — L. Braun, A. Greene, et al. (2003)
• Asbestos and cancer: history and public policy — M.P. Weller (1993)

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