Commentary: the 1968 BOHS Chrysotile Asbestos Standard

Our plain-English summary of Commentary: the 1968 BOHS Chrysotile Asbestos Standard, by T.L. Ogden, British Occupational Hygiene Society (The Annals of Occupational Hygiene, 2003).

The study

• Authors: T.L. Ogden, British Occupational Hygiene Society
• Journal: The Annals of Occupational Hygiene
• Published: 2003;47(1):3-6
• Type of article: Historical article
• Cited by: 6 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Summary of the article

This commentary, published for the British Occupational Hygiene Society's (BOHS) fiftieth anniversary, gave the author's personal view of the background and long-term significance of the Society's 1968 hygiene standard for chrysotile asbestos. The author reviewed earlier asbestos limits from the 1930s onward. He then described how the BOHS sub-committee judged a 1% risk of basal rales, an early sign of asbestosis, to be acceptable and related this sign to exposure in 290 men at Turner's Rochdale factory. The standard estimated the risk at <1% for about 100 fibre-yr/ml, equivalent to 2 fibres/ml over a 50-year working lifetime, and recommended sampling based on 3-month averages. The author summarized the criticisms: only current employees were studied, no disease progression was assumed after exposure ended, early dust levels were guessed, health effects were assessed by a single observer, and cancer was not taken into account. A 1983 BOHS committee put the probability of any of seven adverse effects at 17–20% at 100 fibre-yr/ml. The author traced how 2 fibres/ml spread worldwide, usually applied to single-shift samples. He described how inter-laboratory counting differences made its meaning unclear. He also described how the 1979 Advisory Committee on Asbestos moved away from deriving limits mainly from risk estimates. Britain's current 4 h chrysotile limit was 0.3 fibres/ml, and chrysotile use was prohibited with minor and temporary exceptions. The author concluded that the standard, with all its flaws, was a landmark.

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, described by its author as a personal view, on the history of the British Occupational Hygiene Society's (BOHS) 1968 hygiene standard for chrysotile asbestos. According to the commentary, the 1968 committee related basal rales, which it took as the first sign of asbestosis, to exposure in 290 men at Turner's Rochdale factory. It estimated the risk would be less than 1% at about 100 fibre-years per ml, for example 2 fibres/ml over 50 years. The author noted that this estimate took no account of cancer, and summarized criticisms made by Berry, including that only current employees were studied. A 1983 BOHS committee later put the risk of any of seven adverse effects, still excluding cancer, at 17 to 20% at 100 fibre-years per ml. The 2 fibres/ml figure spread worldwide, although the committee had intended that the upper 90% confidence limit of the 3-month average be below 2 fibres/ml. The author concluded that a risk estimate that could not account for cancer was clearly flawed, and that the standard's influence went far beyond its drafters' expectations.

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 giving the author's personal view of the history and significance of the 1968 BOHS chrysotile standard (a historical review, not a new study)
• Who was studied: No new population was studied. The 1968 standard it discusses was based on 290 men in Turner's Rochdale factory.
• Exposure: Chrysotile asbestos dust, measured in fibres/ml. The 1968 committee used basal rales as the first sign of asbestosis.
• Main results:
  • As described in the commentary, the 1968 standard estimated a risk of basal rales below 1% at a cumulative exposure of about 100 fibre-yr/ml, equivalent for example to 2 fibres/ml over a 50-year working lifetime.
  • The 1968 committee intended a 3-month average whose upper 90% confidence limit was below 2 fibres/ml. In practice, the 2 fibres/ml figure was generally applied to single-shift samples.
  • The simple 2 fibres/ml figure, rather than the proposed sampling strategy, was rapidly spread worldwide.
  • The author considered the greatest weakness of the 1968 risk estimates to be that they did not account for cancer.
  • Berry (1978), as summarized by the author, criticized the underlying 1968 study because it used current employees only and excluded workers who had left.
  • A 1983 BOHS committee concluded that the probability of any one of seven adverse effects, still excluding cancer, was 17–20% at 100 fibre-yr/ml and below 2% at 25 fibre-yr/ml.
  • Doll and Peto (1985), as cited, estimated the overall risk of fatal disease in chrysotile textile manufacture at about 0.5% for an average concentration of 0.25 fibres/ml.
  • Citing McDonald (1984), the author reported that in 1981 nine countries had a 2 fibre/ml limit, including the USA (adopted by OSHA in 1971). Three countries had 5 fibres/ml and Sweden had 1 fibre/ml.
  • Inter-laboratory work by Beckett and Attfield (1974) showed wide differences between laboratories counting the same samples, so the meaning of '2 fibres/ml' was unclear.
  • At the time of writing, the British 4-hour chrysotile limit was 0.3 fibres/ml, and chrysotile use was prohibited with minor and temporary exceptions.
• The authors' conclusion: The author concluded that a risk estimate that could not account for cancer was clearly flawed, and that the standard's influence went far beyond the expectations of those who drew it up. Following Berry, the author viewed the standard as making the best use of available data at a time when the UK had no defined standard.
• Limitations the authors state:
  • The author states the commentary is a personal view, because there is still no consensus on the standard.
  • The author notes that, without records, it is difficult to work out whether the committee relaxed its original 50 fibre-yr/ml figure at industry's request.
  • The author notes that the people consulted are unlikely to agree fully with the commentary.

Topics

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

Medical terms in this study, explained in our Lexicon: Chrysotile, Disease Progression.

Related studies

• Synthetic chrysotile nanocrystals as a reference standard to investigate surface-induced serum albumin structural modifications — P. Sabatino, L. Casella, et al. (2007)
• Asbestos standards: Impact of currently uncounted chrysotile asbestos fibers on lifetime lung cancer risk — D.B. Richardson, A.P. Keil, et al. (2018)
• Mineral phases and some reexamined characteristics of the International Union Against Cancer standard asbestos samples — N. Kohyama, Y. Shinohara, et al. (1996)
• Revising the British Occupational Hygiene Society asbestos standard: 1968-1982 — M. Greenberg (2006)
• On Dr. Dunnigan's commentary linking chrysotile asbestos with mesothelioma — M.R. Becklake (1988)
• Response to Dr. Dunnigan's commentary. The role of chrysotile in the pathogenesis of mesothelioma — J.M. Craighead (1988)

Browse more research in The Annals of Occupational Hygiene, or return to medical research.