Schepers to R. C. Bacon on Talc, Tremolite and the Asbestos Fibre Types (1973)

This document is a letter, not a research study. The author, G.W.H. Schepers, wrote to R. C. Bacon of the R. T. Vanderbilt Company, who had consulted the author about several minerals. The author ranked them by their capacity, in the author's interpretation, to cause biological responses: talc 0, tremolite 1, chrysotile 2+, anthophyllite 3+, amosite 4+ and crocidolite 10+. The author said these views rested on the author's own inhalation experiments, human exposures with necropsy studies, and the literature, but the letter gives no data. The author wrote that pure talc, and tremolite talc, caused only a usually reversible storage effect after excessive prolonged exposure. The author also wrote that fibrosis seen with tremolite came from admixed chrysotile or other asbestos fibers. The author called chrysotile asbestosis relatively mild and said the author had never seen a lung cancer caused by chrysotile alone. The author wrote that crocidolite could cause neoplastic disease after relatively minor exposure. The author suggested chrysotile got a bad name from mixed exposures with amosite, crocidolite or silica.

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From J-M's medical library

This copy comes from the Johns-Manville medical library. It was among the papers J-M kept in its medical library without an index entry.

We publish this piece for research and commentary: it shows what the medical literature in a leading asbestos company's own library said on the subject, and when. Our summary above is our own reading of it. The copyright stays with the publisher.