Effects of the inhalation of asbestos dust on the lungs of asbestos workers: a preliminary study (1935)

This 1935 preliminary report presented data from five US asbestos fabricating plants (A to E), part of a Metropolitan Life Insurance Co. investigation (October 1929 to January 1931) that also studied dust in Canadian asbestos mines and mills. The authors measured airborne dust, X-rayed 126 workers (108 men, 18 women) with more than 3 years of employment, and reviewed insurance claims. Of these, 4 were diagnosed with second-degree asbestosis, 63 first-degree, 39 doubtful and 20 negative. The percentage positive rose with years of exposure. Reviewers noted a very unusual incidence of heart enlargement on the films. Local physicians found no unusual amount of tuberculosis among these workers. An experimental exhaust installation reduced dust by 50 percent. The authors concluded that prolonged asbestos dust exposure caused a lung fibrosis different from silicosis and visible on X-ray, which from this study appeared clinically milder than silicosis, and that a predisposition to tuberculosis was not indicated. They noted that individual cases could not be linked to dust amounts and that small numbers left the role of age undetermined.

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From J-M's medical library

This copy comes from the Johns-Manville medical library. J-M listed it in its medical library index as no. 003012. Barry Castleman cites it in chapter 9, "Company Knowledge", of Asbestos: Medical and Legal Aspects (5th ed., 2005); see Reading Castleman.