Report of a recent "brake" through in the fiber burden-mesothelioma dialogue

Our plain-English summary of Report of a recent "brake" through in the fiber burden-mesothelioma dialogue, by D. Egilman (Inhalation Toxicology, 2012).

The study

• Author: D. Egilman
• Journal: Inhalation Toxicology
• Published: 2012;24(2):136-7
• Type of article: Letter, Comment
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This is a letter to the editor, not a new study. The author disputed a 2011 paper by Marsh and colleagues. That paper concluded that elevated tremolite in brake workers who also had elevated amphibole levels came from concurrent amphibole and chrysotile exposures in jobs other than brake repair. It also concluded that the evidence did not support a role for brake dust in mesothelioma. The author argued, citing company records and testimony, that brake-work settings were not free of commercial amphiboles. For example, Victor/Dana used crocidolite in gaskets until at least 1963. The author also described unpublished data from Dr. Roggli on two workers with pulmonary fibrosis, from 1983 and 1994. The letter stated that their only asbestos exposure was brake work and that both had elevated chrysotile. However, its table, as printed, lists 0 chrysotile for the second case. According to the letter, the cases went unpublished because neither worker had mesothelioma. It stated that in recent testimony Dr. Roggli confirmed that mechanics' exposures can increase lung fiber burden. The author concluded that the Marsh statements were incorrect.

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 responding to a published study (Marsh et al., 2011)
• Who was studied: No study population of its own. The letter discusses Marsh et al.'s brake repair workers and two unpublished cases from Dr. Roggli (Case 1, 1983 and Case 2, 1994). Both were workers with pulmonary fibrosis whose only asbestos exposure was described as work with asbestos brakes.
• Exposure: Brake and friction-product work by automobile mechanics. The author argued this work involved chrysotile and also commercial amphiboles (crocidolite, amosite) used in friction-related components.
• Main results:
  • The letter responds to Marsh et al.'s conclusion about brake workers with elevated amphibole levels. Marsh et al. concluded that the elevated tremolite in these workers came from concurrent exposures in occupational settings other than brake repair.
  • The letter also responds to Marsh et al.'s conclusion that the scientific evidence did not support a role for occupational brake dust exposure in mesothelioma.
  • Citing company documents and testimony, the author stated that Victor/Dana used crocidolite in gaskets until at least 1963. The author also stated that Borg Warner used crocidolite in transmission friction plates and that Ford hygienists were aware of amosite use in brakes.
  • The letter's table, as printed, lists 0 under Chrysotile for Case 2. This does not match the letter's statement that both workers had elevated chrysotile. The column alignment in the scanned text is uncertain.
  • According to the letter, Dr. Roggli did not publish the two brake-worker cases because the patients did not have mesothelioma.
  • The letter reports that in recent testimony Dr. Roggli confirmed that mechanics' exposures can lead to levels of chrysotile and non-commercial amphiboles that increase lung fiber burden.
  • The author argued that working with automobiles can be the source of amphibole lung levels and explains the Marsh et al. results.
• The authors' conclusion: The author concluded that Marsh et al.'s statements were incorrect.

Topics

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

Medical terms in this study, explained in our Lexicon: Fiber Burden, Mesothelioma.

Related studies

• Asbestos fiber concentrations in the lungs of brake repair workers: commercial amphiboles levels are predictive of chrysotile levels — G.M. Marsh, A.O. Youk, et al. (2011)
• Evaluation of the exposure, dose-response and fate in the lung and pleura of chrysotile-containing brake dust compared to TiO2, chrysotile, crocidolite or amosite asbestos in a 90-day quantitative inhalation toxicology study - Interim results Part 1: Experimental design, aerosol exposure, lung burdens and BAL — D.M. Bernstein, B. Toth, et al. (2020)
• Asbestos Fiber Concentrations in the Lungs of Brake Repair Workers: An Updated Analysis Using Several Regression Methods to Handle Nondetectable Measurements — Y. Liu, G.M. Marsh, et al. (2018)
• Fiber burden and patterns of asbestos-related disease in chrysotile miners and millers — A. Churg, J.L. Wright, et al. (1993)
• The analysis of asbestos count data with "nondetects": the example of asbestos fiber concentrations in the lungs of brake workers — M.M. Finkelstein (2013)
• The health effects of chrysotile: current perspective based upon recent data — D.M. Bernstein, J.A. Hoskins (2006)

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