Chrysotile asbestos: enough is enough

Our plain-English summary of Chrysotile asbestos: enough is enough, by M.R. Cullen (Lancet, 1998).

The study

• Author: M.R. Cullen
• Journal: Lancet
• Published: 1998;351(9113):1377-8
• Cited by: 24 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Summary of the article

In this commentary, the author discussed four recent papers by J C McDonald, A D McDonald, F D K Liddell and collaborators on cancer risks among Quebec chrysotile miners and millers. He summarised their finding that virtually all of the mesothelioma and lung cancer risk at the several mines and two large milling centres appeared to come from exposure in the regions most heavily contaminated with tremolite. The dose-response relation was very shallow, and there was no excess of other cancers such as larynx, stomach and colon. The investigators had inferred that pure chrysotile had minimal, if any, potential to cause mesothelioma, that it was much less carcinogenic than the amphiboles, and that it could be used commercially with very little health risk under appropriate exposure controls. The author argued that discrepancies in existing data precluded ready acceptance of these conclusions. He stated that chrysotile had nowhere proven free of mesothelioma risk, and that the difference from amphiboles was perhaps only three-fold. He added that chrysotile products probably remained the world's leading cause of mesothelioma because of their wider use, and that the very high lung cancer rates in chrysotile textile workers could not be explained by tremolite. He acknowledged that a predicted 'third wave' from low-level exposure had shown little evidence of materialising. He concluded that, because safer substitutes exist, putting more asbestos into the environment or relaxing exposure controls would be foolhardy.

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 commentary by the author, not an original study, published in The Lancet in 1998. It responded to four recent papers by J K McDonald, J C McDonald, F D K Liddell and collaborators on cancer risks among chrysotile asbestos miners and millers in Quebec. As the author described those papers, virtually all of the mesothelioma and lung cancer risk seemed to come from exposure in the regions most heavily contaminated with tremolite. Only workers with long and heavy exposure seemed to be at risk above background, and there seemed to be no excess of other cancers. The author disputed the investigators' inference that chrysotile could be used commercially with very little health risk if exposure was controlled. The author argued that chrysotile had nowhere been proven free of mesothelioma risk, and that the difference in risk between fiber types was perhaps three-fold. The author also argued that the very high lung cancer rates in the chrysotile textile industry could not be explained by tremolite. The author concluded that it was premature to liberalise the current stance.

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: Commentary (opinion article) discussing recently published studies; no original data
• Who was studied: No study population of its own; the commentary discussed four recent papers on miners and millers at several mines and two large milling centres in Quebec
• Exposure: Chrysotile asbestos, which the author noted is typically contaminated in nature to varying degrees with the amphibole fibre tremolite; contrasted with the amphiboles crocidolite and amosite
• Main results:
  • As described by the author, the four McDonald/Liddell papers found that virtually all mesothelioma and lung cancer risk in the Quebec miners and millers seemed to come from exposure in the regions most heavily contaminated with tremolite
  • As described by the author, those papers found a very shallow dose-response: only workers with long and heavy exposure seemed to be at risk of lung cancer or mesothelioma above background
  • As described by the author, those papers found no apparent excess of other cancers variably associated with asbestos, such as larynx, stomach and colon
  • One inference the investigators drew, as reported by the author, was that chrysotile could be used commercially with very little health risk provided there are appropriate controls of exposure; the author disputed this
  • The author argued that chrysotile has nowhere been proven free of mesothelioma risk, and that the relative risks between the worst and best cases are only modest, perhaps three-fold
  • The author argued that, because chrysotile is far more widely used than other types of asbestos, exposure to chrysotile products probably remains the leading cause of mesothelioma in the world
  • The author argued that the very high lung cancer rates reported by McDonald and colleagues in the chrysotile textile industry cannot be explained by tremolite contamination
  • The author stated that dire predictions of a 'third wave' epidemic from very low environmental exposure, largely to chrysotile, had shown little evidence of materialising
• The authors' conclusion: The author concluded that it is premature to liberalise the current stance, and called putting more asbestos into the environment or relaxing vigilance over exposure foolhardy while safer substitutes exist

Topics

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

Medical terms in this study, explained in our Lexicon: Chrysotile, Quebec Chrysotile, Mesothelioma, Lung Cancer, Tremolite, Dose-response relationship, Carcinogenic, Amphibole Group.

Related studies

• Comparison of Calidria chrysotile asbestos to pure tremolite: final results of the inhalation biopersistence and histopathology examination following short-term exposure — D.M. Bernstein, J. Chevalier, et al. (2005)
• The importance of fiber biopersistence and lung dose in determining the chronic inhalation effects of X607, RCF1, and chrysotile asbestos in rats — T.W. Hesterberg, G.A. Hart, et al. (1998)
• The carcinogenicity of chrysotile asbestos--a review — W.J. Nicholson (2001)
• The biopersistence of brazilian chrysotile asbestos following inhalation — D.M. Bernstein, R. Rogers, et al. (2004)
• Carcinogenic implications of the lack of tremolite in UICC reference chrysotile — A.L. Frank, R.F. Dodson, et al. (1998)
• Hydrothermal conversion of chrysotile asbestos using near supercritical conditions — K. Anastasiadou, D. Axiotis, et al. (2010)

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