Carcinogenicity of amosite asbestos

Our plain-English summary of Carcinogenicity of amosite asbestos, by I.J. Selikoff, E.C. Hammond, J. Churg (Archives of Environmental Health, 1972).

The study

• Authors: I.J. Selikoff, E.C. Hammond, J. Churg
• Journal: Archives of Environmental Health
• Published: 1972;25(3):183-6
• Cited by: 82 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. 001347).

In plain English

The authors studied deaths among workers at an eastern US factory making amosite insulation, mainly for shipbuilding and ship repair. They followed 230 men who began work in 1941 to 1945, worked at least a year, and were alive on January 1, 1960, through June 30, 1971. Expected deaths came from rates for US white men, without accounting for smoking. There were 105 deaths against 46.4 expected. Twenty-five died of lung cancer, where the authors wrote two or three were expected; their table gives 2.4 expected for lung, pleura, bronchus and trachea cancers combined (27 observed). Fourteen died of asbestosis when virtually none was expected. Five died of mesothelioma (two pleural, three peritoneal); one had earlier chrysotile exposure. Stomach, colon and rectum cancer deaths were also above expected, but the authors said more observation was needed before that association could be regarded as clearly established. The authors reported that only amosite was used at the plant and that no dust-level information was available. The authors concluded that occupational amosite exposure can be associated with serious cancer hazard and that its continued industrial use requires rigorous control.

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: Mortality study of a cohort of factory workers, comparing observed deaths with deaths expected from US population rates
• Who was studied: Men employed at an amosite asbestos products factory in an eastern US city. The factory operated from June 1941 until November 1954. The workers studied began work between June 1941 and December 1945. Of 333 men with at least one year of employment, 88 died by December 31, 1959 and 15 were lost to follow-up. The remaining 230 were alive on January 1, 1960 and were followed through June 30, 1971.
• Exposure: Amosite asbestos only, in the manufacture of amosite insulation, primarily for shipbuilding and ship repair. No information was available on dust levels. Exhaust ventilation was used, and respirators were issued but inconsistently used. Product samples, a stored bag of fiber, workers' respirator filters and lung tissue from deceased workers were examined, and they showed amosite. The lung tissue also contained occasional chrysotile fibrils, which the authors expected in urban dwellers.
• Main results:
  • Among the 230 workers, 105 deaths occurred against 46.4 expected.
  • Lung cancer: 25 deaths occurred. The authors wrote that two or three lung cancer deaths were expected.
  • In Table 3, the expected figure of 2.4 belongs to the combined category of cancer of the lung, pleura, bronchus and trachea, in which 27 deaths were observed.
  • Asbestosis: 14 deaths, when virtually none was expected.
  • Mesothelioma: five deaths, two pleural and three peritoneal.
  • Of the five mesothelioma cases, one had prior chrysotile exposure and four had only amosite exposure.
  • Total cancer, all sites (from the table): 43 deaths observed against 8.5 expected.
  • Deaths from cancer of the stomach, colon and rectum were above expected, with an increase described as only threefold. The authors said further observations are required before this association can be regarded as clearly established.
• The authors' conclusion: The authors concluded that occupational exposure to amosite asbestos can be associated with serious cancer hazard, and that its continued industrial use requires rigorous control.
• Limitations the authors state:
  • The expected death rates did not take smoking habits into account, because the smoking habits of the men were not accurately known.
  • No information was available on dust levels in the plant.
  • Tracing of the wider group of workers was still incomplete for 65 men.

Topics

Medical terms in this study, explained in our Lexicon: Amosite.

Related studies

• Interpretation of the carcinogenicity of amosite asbestos and ferroactinolite on the basis of retained fiber dose and characteristics in vivo — P.M. Cook, L.D. Palekar, et al. (1982)
• Relation between exposure to asbestos and mesothelioma — I.J. Selikoff, J. Churg, et al. (1965)
• The carcinogenicity of dietary acrylamide intake: a comparative discussion of epidemiological and experimental animal research — J.G. Hogervorst, B.J. Baars, et al. (2010)
• Variations in the carcinogenicity of tremolite dust samples of differing morphology — J.M. Davis, J. Addison, et al. (1991)
• A risk assessment for exposure to grunerite asbestos (amosite) in an iron ore mine — R.P. Nolan, A.M. Langer, et al. (1999)
• The carcinogenicity of chrysotile asbestos — J.S. Harington (1991)

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