The origin and development of the asbestos Threshold Limit Value: scientific indifference and corporate influence

Our plain-English summary of The origin and development of the asbestos Threshold Limit Value: scientific indifference and corporate influence, by D.S. Egilman, A.A. Reinert (International Journal of Health Services, 1995).

The study

• Authors: D.S. Egilman, A.A. Reinert
• Journal: International Journal of Health Services
• Published: 1995;25(4):667-96
• Type of article: Review
• Cited by: 15 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Several recent articles have critiqued the process employed by the American Conference of Governmental Industrial Hygienists in determining Threshold Limit Values. Criticisms have included inadequate data collection, inadequate research, excessive corporate influence, and slow response to informational changes. In this article, the authors address the historical development of the American Conference of Governmental Industrial Hygienists' asbestos exposure guideline. They demonstrate that the proposed guideline was known to be inadequate when it was first proposed, was severely criticized between 1946 and 1968, but nonetheless was promulgated annually and remained unchanged 1971.

In plain English

This article was a historical review, not a study of patients or workers. The authors traced how the American Conference of Governmental Industrial Hygienists (ACGIH) set and kept its asbestos exposure guideline, drawing on ACGIH meeting records, published literature and unpublished documents. They reported that in 1946 ACGIH adopted a limit of 5 million particles per cubic foot of air from a 1942 table whose authors had written that it was not to be taken as recommended safe concentrations. The authors traced the figure to a 1938 U.S. Public Health Service study of two North Carolina asbestos textile plants. That study measured total dust, which averaged 9 percent asbestos and cotton fiber. According to the authors, the guideline was reviewed only in 1968. A recommended 10 fibers per milliliter was then misprinted as 12 and published that way for three years. They also described a 1954 Johns-Manville internal fiber limit that was never reported to ACGIH. The authors concluded that "scientific indifference and corporate greed" resulted in an occupational and environmental health disaster.

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 and analysis of how the ACGIH asbestos guideline was set and maintained, based on ACGIH meeting transactions, published literature and unpublished corporate and research documents
• Who was studied: Not a study of people. The subject was the development of the ACGIH asbestos exposure guideline in the United States, mainly from the 1930s to 1971.
• Exposure: Asbestos dust exposure limits. The main one was the guideline of 5 million particles per cubic foot (5 mppcf), first proposed by the U.S. Public Health Service in 1938 and adopted by ACGIH in 1946.
• Main results:
  • In 1946 ACGIH adopted most values from a 1942 table, including the asbestos value of 5 mppcf.
  • The 1942 subcommittee that compiled the table had stated it was not to be taken as recommended safe concentrations.
  • According to the authors, the 1938 study underlying the guideline measured total dust in two North Carolina asbestos textile plants. The average asbestos and cotton fiber content of that dust was 9 percent.
  • The authors reported a 1938 statement by Sayers: a fifth of workers with 50,000,000 to 99,000,000 particle-years of exposure, and half of those with more than 100,000,000 particle-years, had asbestosis. The authors calculated that 40 years at 5 mppcf would amount to 200,000,000 particle-years.
  • The authors found the asbestos guideline was reviewed only in 1968. It was then recommended to be lowered to 2 mppcf or 10 fibers per milliliter.
  • A typographic error printed the 1968 recommendation as 12 fibers per milliliter. The error was acknowledged but never corrected, and the guideline was published that way for 3 years.
  • ACGIH's 1968 documentation stated that the new asbestos guideline was designed to protect workers exposed for thirty years.
  • In 1954 Johns-Manville set an internal guideline of one million asbestos fibers per cubic foot. ACGIH was never informed of it.
  • According to the authors, references to cancer were deleted from Gardner's draft before Vorwald and colleagues published it in 1951. Gardner had found lung cancer in 81.8 percent of mice exposed to asbestos fibers.
  • The authors stated that no asbestos manufacturer placed warnings on product packages explaining the asbestos guideline.
• The authors' conclusion: The authors concluded that companies never relied on the guideline to protect workers, and that ACGIH failed to investigate a safe threshold. In their view, scientific indifference combined with corporate greed resulted in an occupational and environmental health disaster.

Topics

Medical terms in this study, explained in our Lexicon: Threshold Limit Value (TLV), Asbestos Exposure.

Related studies

• Corporate influence on threshold limit values — B.I. Castleman, G.E. Ziem (1988)
• The role of threshold limit values in U.S. air pollution policy — J.C. Robinson, D.G. Paxman (1992)
• Present threshold limit value in the U.S.A. for asbestos dust: a critique — E.L. Schall (1965)
• Talc, Asbestos, and Epidemiology: Corporate Influence and Scientific Incognizance — T.H. Tran, J.E. Steffen, et al. (2019)
• The limits of thresholds: silica and the politics of science, 1935 to 1990 — G. Markowitz, D. Rosner (1995)
• Dust diseases and the legacy of corporate manipulation of science and law — D. Egilman, T. Bird, et al. (2014)

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