Asbestos: Scientific Basis For Environmental Control Of Fibres

Our plain-English summary of Asbestos: Scientific Basis For Environmental Control Of Fibres, by E.D. Acheson, M.J. Gardner (1980).

The study

• Authors: E.D. Acheson, M.J. Gardner
• Published: Biological Effects Of Mineral Fibres (J.C. Wagner, Editor), Lyon: Iarc Scientific Publications, Volume 30, Pp. 737-754 (1980)
• Type of article: Conference paper
• Our copy: from Johns-Manville's own medical library, J-M no. 000783. The article is still under copyright, so we describe it here rather than post it.

In plain English

This was a review paper, not a new study. It looked at the human evidence behind workplace asbestos regulations. The authors discussed problems in measuring dust dose and disease. They then summarized published dose-response data from studies of workers, including Quebec chrysotile miners and millers, New Jersey factory workers and Rochdale textile workers. In the Quebec data they cited, there were 10 pleural mesotheliomas among over 11,000 miners and millers. Mesothelioma risk was almost 10 times greater in the most heavily exposed workers than in the least exposed. In Rochdale data, no cases of certified asbestosis occurred below 50 fibre years per ml. The authors also made their own calculation from the Quebec lung cancer data. A standardized mortality ratio of 110 after 50 years of exposure corresponded to chrysotile levels of 1 to 5 fibres per ml, depending on the conversion factor used. The authors concluded that, within the range of industrial exposure, the balance of evidence was that no 'safe threshold' existed for the conditions discussed, except certified asbestosis. They stressed that the data had many serious shortcomings.

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: Review of published evidence in humans on dose-response relationships for asbestos-related disease, ending with the authors' own illustrative calculations
• Who was studied: Worker groups from published studies, including Quebec chrysotile miners and millers, New Jersey asbestos production and maintenance workers, Rochdale asbestos textile workers, New Orleans/Louisiana asbestos-cement workers, Western Australian crocidolite miners, Nottinghamshire gas-mask makers, and American insulators
• Exposure: Occupational asbestos dust (mainly chrysotile; also amosite, crocidolite and mixtures), measured in fibres per ml or million particles per cubic foot and combined into cumulative dose
• Main results:
  • For lung cancer in the Quebec and New Jersey data, the authors found no evidence of a threshold and judged the data described by a linear hypothesis
  • Citing Steel (1979): because of changes in measurement methods, a chrysotile concentration evaluated as 2 fibres/ml at the time of writing might have been measured as between 0.4 and 1 fibre/ml in 1968
  • In the Quebec data (10 pleural mesotheliomas in over 11,000 miners and millers), the risk of mesothelioma was almost 10 times greater in the most heavily exposed workers than in the least heavily exposed
  • In Rochdale data, no cases of asbestosis certified for compensation occurred below 50 fibre years per ml
  • In the authors' calculations from Quebec data, an SMR of 110 for lung cancer after 50 years' exposure corresponded to chrysotile levels of 1 to 5 fibres per ml, depending on the particle-to-fibre conversion factor
  • Six surveys (Quebec, Louisiana, Rochdale, Finnish anthophyllite miners, Nottingham and Western Australian crocidolite workers) had reported no excess of alimentary tract cancer deaths
• The authors' conclusion: The authors concluded that a linear dose-response was a reasonable working hypothesis for lung cancer. They also concluded that, within industrial exposure ranges, the balance of evidence was that no 'safe threshold' existed for the conditions discussed, except certified asbestosis.
• Limitations the authors state:
  • The authors stated that the available data have many serious shortcomings
  • There were insufficient data to comment on dose-response for alimentary tract cancer and peritoneal mesothelioma
  • The Table 3 calculations were not corrected for personal versus static sampling
  • The Table 3 calculations did not include deaths from other asbestos-related diseases

Topics

Medical terms in this study, explained in our Lexicon: Dose-response relationship, Quebec Chrysotile, Pleural Mesothelioma, Mesothelioma, Lung Cancer, standardized mortality ratio (SMR), Chrysotile.

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