Diatomaceous Earth Pneumoconiosis

This book chapter was a descriptive overview of diatomaceous earth pneumoconiosis, a lung disease of diatomite workers. Diatomite consists of fossilized diatom shells; the largest deposits are in California. Its author was medical director of the Johns-Manville Corporation. The chapter is not about asbestos. The author explained that natural diatomite powders contain only amorphous silica. Calcining and flux-calcining turn some of it into crystalline cristobalite, and flux-calcining also leaves traces of tridymite. The chief symptom was dyspnoea (shortness of breath), which did not correlate with fibrosis seen on X-ray. X-rays showed linear, nodular or coalescent patterns. Coalescent lesions were said to develop only in workers exposed to cristobalite-containing calcined or flux-calcined powders, never with natural powders alone. At one California plant, 65 per cent of employees with coalescent X-ray shadows had negative tuberculin tests and 35 per cent positive. The author stated that the lesion's cause was unknown and an established case had no cure, recommending removal from further exposure and supportive treatment. Preventing dust exposure in the first place was called the only way to control the disease's development.

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.

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 pages from a book 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.