The asbestos TLV: early evidence of inadequacy

Our plain-English summary of The asbestos TLV: early evidence of inadequacy, by D. Egilman, A. Reinert (American Journal of Industrial Medicine, 1996).

The study

• Authors: D. Egilman, A. Reinert
• Journal: American Journal of Industrial Medicine
• Published: 1996;30(3):369-70
• Type of article: Historical article
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This commentary by Egilman and Reinert examined historical documents about the origins of an early airborne asbestos limit. The authors described a 1929 Metropolitan Life Insurance Company dust study at the Johns-Manville plant in Manville, New Jersey, which recorded dust levels of 0.5 to 2.5 million particles per cubic foot (MPPCF) in the textile department. A 1932 Metropolitan Life survey of the plant found positive X-ray findings in 327 of 1,140 workers examined. In the textile department, 115 workers (43% of the department) were positive, and 53 (20%) were classed as asbestosis. The authors noted this may not reflect the true risk, because workers often moved between departments. A draft of a paper by Lanza and co-workers had suggested asbestos might cause pneumoconiosis more readily than free silica. The authors reported that this conclusion was modified after a corporate reviewer, George Hobart, objected. In 1937 Lanza endorsed a five million particle limit in a letter to a Massachusetts official. The authors said the article Lanza relied on did not support that figure. A 5 MPPCF standard, first publicly suggested in 1938, stayed unchanged for thirty years. The authors concluded that Lanza continued to mislead industrial hygienists.

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• Design: Commentary based on historical documents: unpublished company and insurer studies, a draft manuscript, and letters
• Who was studied: Workers at the Johns-Manville plant in Manville, New Jersey, surveyed by Metropolitan Life Insurance Company in 1929 (dust sampling) and 1932 (1,140 workers examined)
• Exposure: Airborne asbestos dust in plant operations, measured in million particles per cubic foot (MPPCF); fiber type not specified
• Main results:
  • In the 1932 Metropolitan Life survey, 327 of the 1,140 workers examined had positive X-ray findings
  • In the textile department, 115 workers (43% of the department) had positive cases; of these, 53 (20%) were classed as asbestosis (positive cases whose dust exposure came only from Manville employment)
  • The 1929 study reported textile department dust exposure of 0.5 to 2.5 MPPCF
  • A draft of the Lanza et al. paper suggested asbestos may cause pneumoconiosis more readily than free silica. Corporate reviewer George Hobart asked that this part of the conclusion be removed, and the authors reported that the published conclusion was modified accordingly
  • In 1937 Lanza told a Massachusetts official that five million particles was a fair threshold limit. The authors stated that the article Lanza cited had said permissible limits could not be determined on a medical basis
  • A 5 MPPCF standard for asbestos was first publicly suggested in 1938 and remained unchanged for thirty years
• The authors' conclusion: The authors concluded that the Metropolitan Life studies indicated exposures of 0.5 to 2.5 MPPCF may cause asbestos-related lung disease, that this was never published, and that Lanza continued to mislead industrial hygienists about appropriate exposure levels
• Limitations the authors state:
  • The 20% asbestosis figure in the textile department may not reflect the true risk of working there, because workers were often transferred between departments

Topics

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

Related studies

• The silence: the asbestos industry and early occupational cancer research--a case study — D.E. Lilienfeld (1991)
• Asbestos and cancer: an early warning to the British TUC — N.J. Wikeley (1992)
• Corporate corruption of medical literature: asbestos studies concealed by W.R. Grace & Co — D. Egilman, W. Wallace, et al. (1998)
• Early animal research on asbestos cancer — P.E. Enterline (1993)
• An early study of pulmonary asbestosis among manufacturing workers: original data and reconstruction of the 1932 cohort — S.W. Borron, S.A. Forman, et al. (1997)
• Evidence for an amphibole asbestos threshold exposure for asbestosis assessed by autopsy in South African asbestos miners — G.K. Sluis-Cremer, E. Hnizdo, et al. (1990)

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