Silicate Pneumoconioses

Our plain-English summary of Silicate Pneumoconioses, by A. Seaton (1975).

The study

• Author: A. Seaton
• Published: Occupational Lung Diseases (W.K.C. Morgan And A. Seaton, Editors), Philadelphia: W.B. Saunders, Pp. 112-123 (1975)
• Type of article: Book excerpt
• Our copy: from Johns-Manville's own medical library, J-M no. 002867.

In plain English

This textbook chapter reviewed lung disease from silicates other than asbestos, which the book covered separately. The silicates reviewed were talc, sericite, sillimanite, fiberglass, kaolin, fuller's earth, cement, nepheline and mica. It reported no new study of its own. The author noted that talc deposits usually also contain chrysotile, anthophyllite or tremolite. A cited analysis of 22 talc products found a fiber content of 8 to 30 per cent by count, with a mean of 19 per cent. In a cited study of 220 New York State talc miners and millers employed before 1940 with fifteen or more years' talc exposure, ninety-one had died by 1967. Their lung cancer death rate was almost four times that expected. Their smoking habits were unknown, and the relative contributions of talc and asbestos remained uncertain. A cited comparison of fiberglass workers with matched controls found no difference in respiratory findings. The author concluded that, apart from miners and millers also exposed to asbestos, there was little evidence that talc causes cancer. The author added that an open mind should be kept.

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: Review chapter in a textbook, summarizing published reports on silicate pneumoconioses
• Who was studied: No original study population. The chapter reviewed published reports on workers exposed to talc, sericite, sillimanite, fiberglass, kaolin, fuller's earth, cement, nepheline and mica, in the United States, Britain, Egypt, Canada and elsewhere.
• Exposure: Silicate dusts, including talc. Talc is chemically related to chrysotile, anthophyllite and tremolite, and talc deposits usually contain one or more of these minerals.
• Main results:
  • A cited analysis of 22 commonly available talc products found a fiber content of between 8 and 30 per cent by count, with a mean of 19 per cent.
  • A cited study followed 220 miners and millers in New York State who were employed before 1940 and had fifteen or more years' exposure to talc. By 1967, ninety-one of them had died.
  • Among the deaths in the New York talc miners and millers, 31 per cent were from pneumoconiosis and 21 per cent from neoplasms. The neoplasms included nine lung cancers and one 'fibrosarcoma' of the pleura.
  • In the New York talc miners and millers, the lung cancer death rate was almost four times that expected. The deaths occurred mainly in the seventh decade of life.
  • The author wrote that calcified plaques on the diaphragm can occur in talc pneumoconiosis, as in asbestosis, and may be due to contaminating asbestos.
  • A cited comparison of seventy fiberglass workers with age- and sex-matched controls found no difference in respiratory symptoms, radiographic findings or ventilatory capacity.
  • In a cited report, Smith found pleural calcification in five of 302 workers producing mica insulators. Smith suggested that mica, like talc and asbestos, might be the cause.
• The authors' conclusion: The author concluded that, apart from miners and millers who are also exposed to asbestos, there is little epidemiological or experimental evidence that talc is a carcinogen. Because commercial talc contains fibers, the author said an open mind should be maintained, and called for epidemiological studies of workers with prolonged exposure to commercial talc.
• Limitations the authors state:
  • In the cited New York talc mortality study, the men's smoking habits were not known, and the relative contributions of talc and asbestos remained uncertain.
  • Talc contains asbestos fibers and silica, which made it hard to tell whether talc itself or a contaminant caused disease in exposed people.
  • No systematic studies of workers using commercial talc had been reported.

Topics

Medical terms in this study, explained in our Lexicon: Silicate, Talc, Mica, Chrysotile, Anthophyllite, Tremolite, Lung Cancer, Habit.

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