The Effects Of Inhaled Talc-Mining Dust On The Human Lung

Our plain-English summary of The Effects Of Inhaled Talc-Mining Dust On The Human Lung, by G.W.H. Schepers, T.M. Durkan (1955).

The study

• Authors: G.W.H. Schepers, T.M. Durkan
• Published: Archives Of Industrial Health 12(2):182-197, August (1955)
• Type of article: Journal article
• Our copy: from Johns-Manville's own medical library, J-M no. 001877. The article is still under copyright, so we describe it here rather than post it.

In plain English

The authors, from The Saranac Laboratory, surveyed dust in tremolite talc mines and mills of Northern New York State and examined the lungs of eight deceased employees. The commercial talc was a mixture of talc, tremolite and anthophyllite, with quartz in the dust. Two airborne samples from Mine A contained 7% and 2% quartz. Miners had drilled rock for 10 months to 27 years; five of the eight had also mined lead, zinc or pyrites. A basic lung lesion appeared throughout the series. 'Talc bodies' were somewhat longer and thinner than asbestos bodies of asbestosis; the authors inferred they were of tremolite origin. Five lungs held quartz in amounts compatible with nodular silicosis, yet it was absent in three and sparse in two. Marked vascular damage occurred where lung quartz was highest. The authors concluded that tremolite may be the main cause of the 'talc' lesion, not wholly excluding talc and anthophyllite. They noted limited knowledge of the dusts each man breathed; the mill worker's findings were of limited value because his body was exhumed 18 months after death.

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: Dust survey of mines and mills plus a case series of eight autopsied lungs examined chemically, mineralogically and microscopically
• Who was studied: Eight deceased employees of the tremolite talc industry of Northern New York State. The miners had drilled rock for 10 months to 27 years. One mill worker (Case 3) had been employed six years. Five of the eight had also been miners of lead, zinc, or pyrites.
• Exposure: Dust from mining and milling commercial talc, described as a mixture of talc, tremolite and anthophyllite, with moderate amounts of quartz in the dust. Some workers also had associated exposures as miners of zinc, lead, coal and iron pyrites.
• Main results:
  • In Mine A, one airborne dust sample had a quartz content of 7%, while another collected at a different level had only 2%.
  • A basic lung lesion was recognized throughout the series of eight cases, modified in some cases by other dusts.
  • In Case 7, one of the two key cases of 'pure talc pneumoconiosis', the quartz content of the lung ash was 3.2%. The authors said this was about the same as in many normal persons never exposed industrially to quartz.
  • In five cases (Cases 1, 2, 4, 5 and a fifth whose number is damaged by OCR) lung quartz was present in concentrations compatible with nodular silicosis. The Saranac average for silicosis cases is 9.3% of lung ash. Even so, nodular silicosis was absent in Cases 2, 4 and 6 and only sparsely present in Cases 1 and 5.
  • The 'talc bodies' found were somewhat longer and thinner than the asbestos bodies generally found in asbestosis. They were sparse in Cases 1, 6 and 8, the cases with the least tremolite in lung ash, and the authors inferred they were of tremolite origin.
  • The authors saw no apparent correlation in this series between length of exposure and the concentration of talc, tremolite and anthophyllite in lung ash.
  • Marked pulmonary vascular damage was present in the cases with the highest lung quartz content. The authors considered this in harmony with a tendency to cardiac deaths.
• The authors' conclusion: The authors concluded that the histological features suggest tremolite may be the main pathogenic agent in the characteristic 'talc' lung lesion, though the role of talc and anthophyllite has not been wholly excluded. They also concluded that quartz modifies the talc reaction, and that talc dust modifies both the response to quartz and the course of associated infection.
• Limitations the authors state:
  • The authors lacked sufficient knowledge of the differences in the talc dusts the men were exposed to, and of the concentration and rate at which the dust was deposited.
  • The mill worker's (Case 3) body was exhumed 18 months after death, so those findings are of limited value.
  • The lung-ash values for talc, tremolite and anthophyllite are only approximate and may be above or below the true value.
  • The authors described the series of eight cases as appearing limited.
  • Histoplasmosis may have been a factor in some of the lesions, because the cases came from the St. Lawrence Valley area during an epidemic there.

Topics

Medical terms in this study, explained in our Lexicon: Talc, Saranac Laboratory, Tremolite, Anthophyllite, Asbestos Bodies, Silicosis.

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