Malignant mesothelioma, airborne asbestos, and the need for accuracy in chrysotile risk assessments

Our plain-English summary of Malignant mesothelioma, airborne asbestos, and the need for accuracy in chrysotile risk assessments, by C. Meisenkothen (New Solutions, 2013).

The study

• Author: C. Meisenkothen
• Journal: New Solutions
• Published: 2013;23(2):389-405
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

A man diagnosed with pleural mesothelioma sought legal representation with the author's law firm. He worked 33 years in a wire and cable factory in the northeastern United States (Connecticut) that exclusively used chrysotile asbestos in its manufacturing process. This is the first report of mesothelioma arising from employees of this factory. This report provides additional support for the proposition that chrysotile asbestos can cause malignant mesothelioma in humans. If chrysotile risk assessments are to be accurate, then the literature should contain an accurate accounting of all mesotheliomas alleged to be caused by chrysotile asbestos. This is important not just for public health professionals but also for individuals and companies involved in litigation over asbestos-related diseases. If reports such as these remain unknown, it is probable that cases of mesothelioma among chrysotile-exposed cohorts would go unrecognized and chrysotile-using factories would be incorrectly cited as having no mesotheliomas among their employees.

In plain English

This case report was written by a lawyer whose law firm the patient approached for representation. The author discloses representing plaintiffs in asbestos litigation. It described an 89-year-old man with right-sided malignant pleural mesothelioma, confirmed by pleural biopsies and staining. He had worked 33 years at a Connecticut wire and cable factory that used only chrysotile asbestos in manufacturing from 1920 to 1986. A consulting expert in the litigation concluded that the case also met clinical criteria for asbestosis. He died 6 months after diagnosis. Company air tests from 1971 to 1981 (55 measurements) ranged from not detectable to 0.94 fibers/cc, with a mean of 0.28 and a median of 0.20. All were below the limits in force at the time, but 38 (69%) were above the OSHA limit current at publication, 0.1 fibers/cc. One pipe insulation product may have contained 10 percent amosite, and the author noted likely trace tremolite/actinolite in the chrysotile. No lung fiber analysis was available. A second worker's case was excluded because of mixed exposures. The author concluded that the report supports the proposition that chrysotile can cause pleural mesothelioma in humans.

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: Case report of one worker, written by a lawyer whose firm the patient approached; it includes the company's air sampling data
• Who was studied: One 89-year-old Caucasian man with right-sided malignant pleural mesothelioma who worked at a wire and cable factory in Connecticut, U.S.A.
• Exposure: 33 years of work at a wire and cable factory that used chrysotile asbestos in manufacturing. He operated respooling machines and machines that coated wires with asbestos, and did sweeping and other odd jobs.
• Main results:
  • The factory used only chrysotile asbestos in parts of its manufacturing process between 1920 and 1986.
  • The diagnosis of mesothelioma (biphasic) was confirmed by three pleural biopsies and immunohistochemical staining.
  • A consulting expert in the litigation concluded that the case met clinical criteria for asbestosis.
  • The patient died 6 months after diagnosis.
  • Across the company's 55 air measurements taken from 1971 to 1981, levels ranged from not detectable to 0.94 fibers/cc, with a mean of 0.28 fibers/cc and a median of 0.20 fibers/cc.
  • All 55 measurements were below the exposure limits in effect when they were taken (5.0 fibers/cc recommended by ACGIH, later 2.0 fibers/cc set by OSHA).
  • Of the 55 measurements, 38 (69%) were above the OSHA limit current at publication of 0.1 fibers/cc, 15 (27%) were exactly at it, and 2 (3.6%) were zero or not detectable.
  • One brand of pipe insulation used in parts of the plant may have contained 10 percent amosite asbestos or chrysotile alone, depending on the manufacturer.
  • A second worker from the same factory developed pleural mesothelioma. He was excluded from the analysis because of other mixed exposures over his life.
• The authors' conclusion: The author concluded that the report provides additional support for the proposition that chrysotile can cause pleural mesothelioma in humans. The author also concluded that the literature should account for all mesotheliomas alleged to be caused by chrysotile.
• Limitations the authors state:
  • No lung tissue fiber burden analysis was available; whether suitable tissue remains was unknown.
  • The author stated that it is difficult to rule out hidden amphibole exposure.
  • The author noted that the chrysotile used in the factory was probably contaminated with traces of tremolite/actinolite.
  • The author disclosed a competing interest: the author represents plaintiffs in asbestos litigation.

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: Malignant Mesothelioma, Chrysotile, Pleural Mesothelioma, Mesothelioma.

Related studies

• Malignant mesothelioma among employees of a Connecticut factory that manufactured friction materials using chrysotile asbestos — M.M. Finkelstein, C. Meisenkothen (2010)
• Mesothelioma in a connecticut friction plant: the need for transparency and exposure information in attribution of risk — M.J. Teta (2011)
• Airborne asbestos exposures associated with work on asbestos fire sleeve materials — C.L. Blake, S.C. Harbison, et al. (2011)
• A study of airborne chrysotile concentrations associated with handling, unpacking, and repacking boxes of automobile clutch discs — G.C. Jiang, A.K. Madl, et al. (2008)
• Spatio-seasonal variation, distribution, levels, and risk assessment of airborne asbestos concentration in the most industrial city of Iran: effect of meteorological factors — M. Kermani, A. Jonidi Jafari, et al. (2021)
• Exposure to airborne asbestos during removal and installation of gaskets and packings: a review of published and unpublished studies — A.K. Madl, K. Clark, et al. (2007)

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