Experimental asbestos studies in the UK: 1912-1950

Our plain-English summary of Experimental asbestos studies in the UK: 1912-1950, by M. Greenberg (American Journal of Industrial Medicine, 2017).

The study

• Author: M. Greenberg
• Journal: American Journal of Industrial Medicine
• Published: 2017;60(11):956-962
• Type of article: Historical article
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The asbestos industry originated in the UK in the 1870s. By 1898, asbestos had many applications and was reported to be one of the four leading causes of severe occupational disease. In 1912, the UK government sponsored an experimental study that reported that exposure to asbestos produced no more than a modicum of pulmonary fibrosis in guinea pigs. In the 1930s, the newly established Medical Research Council, with assistance from industry, sponsored a study of the effects of exposing animals to asbestos by injection (intratracheal and subcutaneous) and by inhalation in the factory environment. Government reports, publications, and contemporary records obtained by legal discovery have been reviewed in the context of the stage of scientific development and the history of the times. Experimenters were engaged in a learning process during the 1912-1950 period, and their reports of the effects of asbestos were inconsistent. Pathologists who studied the effects of asbestos experimentally, at whole animal, tissue and cellular levels, advanced experimental methodology and mechanistic knowledge. In the hands of public relations experts, however, research was exploited to preserve an industry and perpetuate preventable diseases, a practice that continues to this day.

© 2017 Wiley Periodicals, Inc.

In plain English

This is a single-author historical review of experimental animal and tissue studies of asbestos in Britain from 1912 to 1950. The author used government reports, publications, and company records obtained through legal discovery. A 1912 government-sponsored experiment found that heavy asbestos exposure produced a mild degree of lung fibrosis in guinea pigs. Guinea pigs kept in an asbestos factory for 12 to 20 weeks developed asbestosis bodies but no appreciable fibrosis of the alveolar walls. Wartime tissue culture work concluded that, under its conditions, small amounts of asbestos had little or no toxic effect, and gave no better understanding of asbestosis in humans. Largely company-funded rat studies at the Postgraduate Medical School had high death rates. Across 22 wartime experiments, only 144 of 346 rats were alive. In a post-war experiment, 109 of 150 rats had died, mostly within 20 days of dosing. A later published rat study using chrysotile concluded that added alumina increased fibrosis. The author concluded that experimenters were in a learning process and reported inconsistent effects, and that public relations experts exploited the research to preserve the industry.

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: Historical review of experimental (animal and tissue culture) asbestos studies, based on government reports, publications, and records obtained by legal discovery
• Who was studied: Experimental asbestos studies conducted in Britain from 1912 to 1950, using guinea pigs, mice, rats, rabbits, and cell and tissue cultures (including chick embryo, rat embryo and human fetal tissue)
• Exposure: Asbestos dusts given by inhalation in dust chambers or factories, by subcutaneous injection and by intratracheal instillation. Fibers named include white (chrysotile) and blue (crocidolite) asbestos wool, Canadian asbestos fiber, and Rhodesian and Canadian chrysotile, crocidolite and amosite. Short (nominally 2.5 μm) and long (15 μm) fibers were tested, some combined with alumina or aluminum.
• Main results:
  • In the 1912 study, guinea pigs were exposed for 3 hours a day to a total of 68 hours. Heavy asbestos exposure produced a mild degree of lung fibrosis. The author found no record of a formal report.
  • In guinea pigs caged in an asbestos factory for 12 to 20 weeks, Stewart reported well-developed asbestosis bodies but no appreciable fibrosis of the alveolar walls
  • Kettle injected dusts under the skin of mice. Both silica and asbestos produced marked local reactions with tubercle bacilli. Because this conflicted with human experience, the author wrote that the subcutaneous route had serious limitations as a model.
  • The tissue culture study authors concluded that, under the conditions of their experiments, small amounts of asbestos had little or no toxic effect. They also concluded that the experiments led to no better understanding of how asbestosis is produced in humans.
  • Belt reported on 22 wartime rat experiments conducted since November 1941. Early mortality was high, attributed to doses being too large. Only 144 rats were alive out of a total of 346. The wartime results were not published.
  • In a post-war rat experiment, 109 of 150 rats (five groups of 30) were already dead, mostly within 20 days of dosing. By December 1947, 25 of the original 150 had survived.
  • In the published rat study using Rhodesian chrysotile, 20 animals were given short fibers for up to 483 days. Slight interstitial fibrosis was present in only 3 of them.
  • In the same rat study, most of the 14 rats examined in the long-fiber group had moderate interstitial pulmonary fibrosis
  • The rat study authors concluded that alumina injected with asbestos increased the fibrosis produced
  • In the rabbit study using Rhodesian chrysotile, the authors concluded that adding aluminum gave no benefit
• The authors' conclusion: The author concluded that experimenters in 1912 to 1950 were engaged in a learning process and reported inconsistent effects. The author also concluded that research was exploited by public relations experts to preserve the industry and perpetuate preventable diseases, a practice the author said continues today.
• Limitations the authors state:
  • The author could not obtain records from the Postgraduate Medical School archives on the commissioning or conduct of the asbestos studies
  • The company documents obtained through litigation were not comprehensive
  • No formal report or publication of Beattie's 1912 asbestos study was found
  • Progress reports on the wartime rat studies were not found beyond November 1943

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis, Lung cancer, Mesothelioma.

Medical terms in this study, explained in our Lexicon: Occupational Disease, Pulmonary Fibrosis, Discovery.

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