The Dust Hazard In Tremolite Talc Mining, Including Roentgenological Findings In Talc Workers

Our plain-English summary of The Dust Hazard In Tremolite Talc Mining, Including Roentgenological Findings In Talc Workers, by W. Siegel, A.R. Smith, L. Greenburg (1943).

The study

• Authors: W. Siegel, A.R. Smith, L. Greenburg
• Published: American Journal Of Roentgenology 49(1):11-29, January (1943)
• Type of article: Journal article
• Our copy: from Johns-Manville's own medical library, J-M no. 001966. The article is still under copyright, so we describe it here rather than post it.

In plain English

This 1943 article reported an X-ray survey of talc miners and millers in St. Lawrence County, northern New York State, made in 1940-1941. It also reported dust measurements in three talc mines and five mills, and summaries of compensation claims. The talc there was a fibrous 'asbestine' type mixed with tremolite and anthophyllite, with 1 per cent or less free silica. Of 221 men X-rayed, 32 (14.5 per cent) had advanced fibrosis. Men with only slight or moderate fibrosis were not counted. All 32 were among the 107 men with ten or more years in talc (29.9 per cent of that group). Among men aged fifty and older, fibrosis was found in 51.5 per cent of talc workers and 4.9 per cent of carpet factory workers. Clinically significant tuberculosis was seen in 5 of the 221 (2.2 per cent). Opaque deposits on the pleural surfaces, which the authors called 'talc plaques', were seen in 14 men (6.3 per cent). The authors concluded that tremolite talc, like asbestos, can cause a disabling pneumoconiosis. They called their tuberculosis evidence suggestive and noted the number of cases was small.

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: Cross-sectional X-ray (roentgen) survey of talc workers, with a follow-up examination of 28 men after ten months, dust sampling in mines and mills, and summaries of compensation claim cases
• Who was studied: 221 talc miners and millers from seven plants in St. Lawrence County, northern New York State, examined in 1940-1941. Dust studies covered three talc mines and five talc mills. For comparison, 266 carpet factory workers previously examined by the authors were included.
• Exposure: Dust of fibrous 'asbestine' talc mingled with tremolite and anthophyllite, with 1 per cent or less free silica. Average mine dust counts where no exhaust device was used were 1,350 (drilling), 1,290 (stoping), 35 (mucking) and 17 (general air) million particles per cubic foot. Mill counts ranged from 20 to 215 million particles per cubic foot. Paper bagging averaged 163 million particles per cubic foot in three mills.
• Main results:
  • Advanced fibrosis was found in 32 of the 221 talc miners and millers (14.5 per cent). Slight or moderate fibrosis was not counted.
  • All 32 cases of fibrosis were among the 107 men who had worked in tremolite talc for ten years or longer, an incidence of 29.9 per cent in that group. No cases occurred in workers with less than ten years' exposure.
  • Of the 8 men who had worked thirty or more years in talc, 6 showed fibrosis. The article prints this as 74 per cent.
  • Among men fifty years of age and older, fibrosis was present in 51.5 per cent of talc workers and in 4.9 per cent of carpet factory workers. It was present in 2.5 per cent of all carpet workers.
  • Of 18 men with marked fibrosis whose only significant dust exposure had been to talc, 15 worked in the mills and 3 were miners. Thirteen of the 18 had one or more lung symptoms.
  • Of the 221 talc workers, 5 (2.2 per cent) had clinically significant tuberculosis on X-ray. The authors described this as slightly higher than the average of about 1.2 per cent in most industrial groups. Among the 18 fibrosis cases exposed only to talc, tuberculosis appeared as a complication in 3 (16.6 per cent).
  • Opaque deposits, called 'talc plaques', were seen on pleural surfaces including the diaphragm and pericardium in 14 of the 221 workers (6.3 per cent). These men were aged thirty-five to seventy-seven and had 4 to 52 years of talc exposure. Ten were mill workers and 4 were miners. Marked fibrosis coexisted in 7. No symptoms or signs could be attributed to the deposits.
  • The authors compared the talc workers' films with films of workers with early asbestosis. They found the talc fibrosis resembled early asbestosis in its fineness, diffuseness and hazy 'ground glass' quality.
  • Six compensation claims for disability from talc dust in New York State were described: 4 from talc mining and milling, one from talcum powder manufacture and one from a shoe factory. Five of the 6 cases were fatal.
• The authors' conclusion: The authors concluded that tremolite talc is a silicate dust that, like asbestos, can cause a disabling pneumoconiosis, with evidence of an association with increased susceptibility to tuberculosis. They concluded that exposure to tremolite talc dust is an industrial hazard requiring dust control by engineering methods.
• Limitations the authors state:
  • The authors stated that the number of cases was small and that the evidence linking tremolite talc exposure with increased susceptibility to tuberculosis was only suggestive.

Topics

Medical terms in this study, explained in our Lexicon: Tremolite, Talc, Anthophyllite, Fibrosis, Pneumoconiosis.

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