In reply: asbestos, carcinogenicity, and public policy

Our plain-English summary of In reply: asbestos, carcinogenicity, and public policy, by W.J. Nicholson, E.M. Johnson, J.S. Harington, et al (Science, 1990).

The study

• Authors: W.J. Nicholson, E.M. Johnson, J.S. Harington, J. Melius, P.J. Landrigan
• Journal: Science
• Published: 1990;248(4957):796-9
• Cited by: 11 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. 003818).

Summary of the article

In this letter, the authors responded to an article by Mossman et al. in Science that supported the "amphibole hypothesis" and suggested little cancer risk from chrysotile asbestos. They argued that lung burdens of fiber types were nearly worthless for predicting mesothelioma, because chrysotile can disappear from lung tissue and tremolite burden is proportional to chrysotile inhaled. They cited four studies of mainly chrysotile textile workers, in which lung cancer risk rose by 1.0 to 2.8% per fiber-year per cubic centimeter. In five studies of amosite or mixed exposures the rise was 0.5 to 4.3%, and for crocidolite miners it was 2.1 to 5.8%. They also cited rat inhalation studies in which chrysotile produced the most cancers for equal exposures, findings that short chrysotile fibers outnumbered amphiboles in pleural tissue, and evidence that chrysotile transfers DNA into cells. They criticized the building air data used by Mossman et al., noting that no fibers were found in 83% of samples and that short-term sampling misses episodic releases. Agency estimates gave 4 to 12 cancer deaths per 100,000 for a 13-year school exposure at 0.002 fiber per cubic centimeter, or 800 to 2400 cases among 20 million pupils. They concluded that the EPA's school asbestos regulation was in the mainstream of U.S. regulatory action.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.

In plain English

This was a letter to the editor of Science, not a new study. The authors replied to an article by Mossman et al. that they believed could mislead the public about chrysotile asbestos. Drawing on earlier studies, they argued against the "amphibole hypothesis" that tremolite, amosite and crocidolite carry much greater cancer risk than chrysotile. They reported that in four earlier studies of mainly chrysotile asbestos-textile workers, lung cancer rose 1.0 to 2.8% per fiber-year per cubic centimeter of cumulative exposure. In studies of mixed chrysotile-amphibole exposures the figure was 0.5 to 4.3%, and in pure crocidolite miners it was 2.1 to 5.8%. Citing three U.S. agencies' calculations, they stated that a 13-year exposure beginning at age 5 to 0.002 fiber per cubic centimeter gave a lifetime risk of 4 to 12 asbestos cancer deaths per 100,000, or 800 to 2400 excess cancers among 20 million pupils. The authors concluded that the school risks the EPA sought to reduce were in the mainstream of U.S. regulatory action. They added that the EPA treats removal as the option of last resort.

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: Letter to the editor replying to an article by Mossman et al.; no new data, it discusses earlier studies and agency risk estimates
• Who was studied: No population of its own; the letter discusses earlier studies of asbestos-textile workers, miners and millers, rats, and school and building air measurements
• Exposure: Chrysotile asbestos compared with the amphiboles tremolite, amosite and crocidolite; asbestos in buildings and schools
• Main results:
  • The authors cited four earlier studies of asbestos-textile workers exposed primarily to chrysotile, in which the increase in lung cancer ranged from 1.0 to 2.8% per fiber-year per cubic centimeter of cumulative exposure
  • The authors cited five other earlier studies of mixed chrysotile-amphibole or 100% amosite exposures. The risk ranged from 0.5 to 4.3% per fiber-year per cubic centimeter, which the authors described as the same as for mainly chrysotile exposures within statistical uncertainty
  • The authors cited a study in which miners with pure crocidolite exposure showed a 2.1 to 5.8% increase per fiber-year per cubic centimeter
  • The authors cited rat inhalation experiments by Wagner et al. in which chrysotile produced the greatest numbers of cancers for equal exposures. In those experiments, amphibole fiber mass in the lungs was about 15 times that of chrysotile
  • The authors noted that no asbestos fibers were observed in 83% of the building air samples reviewed by Mossman et al. They suggested the analytical techniques may have been inadequate
  • The authors cited a study by Sawyer in which concentrations of 1 to 18 fibers per cubic centimeter were measured during the changing of light fixtures or removal of a ceiling panel
  • The authors cited calculations by the CPSC, the National Academy of Sciences and the EPA for a 13-year exposure beginning at age 5 at 0.002 fiber per cubic centimeter. These gave a lifetime risk ranging from 4 to 12 asbestos cancer deaths per 100,000, which the authors translated into 800 to 2400 excess cancers for 20 million pupils
  • At the 0.00024 level suggested by Mossman et al., the authors stated that lifetime mortality for the current school population would still range from 100 to 300 asbestos cancers
  • The authors cited a review of regulatory actions by the FDA, CPSC and EPA. In that review, only 8 of 31 carcinogenic exposures above a one-in-a-million lifetime risk level (where population risk exceeded one death per year) were not regulated
  • The authors stated that average asbestos lifetime cancer risks in school buildings range from 0.5 to 10 per 100,000 for a 13-year exposure
• The authors' conclusion: The authors concluded that the risks the EPA is trying to reduce in school buildings under the Asbestos Hazard Emergency Response Act are in the mainstream of U.S. regulatory action. They noted that the EPA requires inspection and an operations and maintenance program, with removal as the option of last resort

Topics

Medical terms in this study, explained in our Lexicon: amphibole hypothesis, Chrysotile, Mesothelioma, Tremolite, Lung Cancer, Amosite, Crocidolite, Amphibole Group.

Related studies

• In reply: asbestos, carcinogenicity, and public policy — B.T. Mossman, J. Bignon (1990)
• In reply: asbestos, carcinogenicity, and public policy — S.W. Samuels (1990)
• In reply: asbestos, carcinogenicity, and public policy — K.S. Crump (1990)
• Reply to letter by Nolan and colleagues--re: the carcinogenicity of New York state talc dusts in humans — M. Finkelstein (2013)
• Asbestos: scientific developments and implications for public policy — B.T. Mossman, J. Bignon, et al. (1990)
• Naturally occurring asbestos: a recurring public policy challenge — R.J. Lee, B.R. Strohmeier, et al. (2008)

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