The dust hazard in tremolite talc mining

Our plain-English summary of The dust hazard in tremolite talc mining, by L. Greenburg (The Yale Journal of Biology and Medicine, 1947).

The study

• Author: L. Greenburg
• Journal: The Yale Journal of Biology and Medicine
• Published: 1947;19(4):481-501
• Cited by: 7 articles, as counted by NIH iCite
• Read it: PubMed · Free full text
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 001940).

Abstract

1. A study of the tremolite talc mining and milling industry in northern New York State is reported. 2. Talc in this region is of the asbestine variety, mingled with tremolite and anthophyllite. Analyses of material from both mines and mills gave consistently a free silica content of 1 per cent or less. Microscopic studies of dust showed the presence of fine, straight, needle-like fibers. 3. Dust counts in mining ranged from 6 to 5,000 million particles per cubic foot; in milling from 20 to 215 million particles per cubic foot. 4. In a group of 221 tremolite talc miners and millers, advanced fibrosis was found in 32 men, giving an incidence of 14.5 per cent. 5. All of the cases of fibrosis occurred among those men who had worked in tremolite talc for ten years or longer (107 men), giving an incidence for this group of 29.9 per cent. 6. The fibrosis found in this study was of a fine, diffuse type with a roentgenographic appearance of granulation or nodulation on a hazy background. It tended to be disabling in character and was frequently accompanied by dyspnea, cough, and fatigue. 7. There was also some evidence that this fibrosis was characterized by an increased susceptibility to tuberculosis. Clinically significant tuberculosis was diagnosed by roentgen examination in 3 of 18 cases of tremolite talc fibrosis where there had been no other dust exposure. 8. In addition to fibrosis, deposits of unidentified opaque material in the periphery of the lungs, including the region of the diaphragm and pericardium, designated as "talc plaques," were observed in 6.3 per cent of all tremolite talc workers examined. These deposits occurred independently of other lung pathology and could not be identified with any particular signs or symptoms.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.

In plain English

This report described a survey of tremolite talc mining and milling in St. Lawrence County, northern New York State. Engineers measured dust in three mines and five mills, and 221 men from seven plants had chest X-rays in 1940. The talc was a fibrous variety called asbestine, found with tremolite and, according to another investigator, anthophyllite. Samples contained 1 per cent or less free silica. Marked fibrosis (lung scarring) was seen in 32 of the 221 men (14.5 per cent). All 32 were among the 107 men with ten or more years in talc (29.9 per cent). Among 266 carpet workers examined earlier, 2.5 per cent showed fibrosis. Of 18 men with fibrosis whose only dust exposure was talc, 13 had lung symptoms and 3 appeared to have clinically significant tuberculosis. On X-rays, 14 workers (6.3 per cent) showed what appeared to be deposits of unidentified opaque material, which the authors called "talc plaques". No symptoms could be attributed to these deposits. The authors concluded that tremolite talc, like asbestos, can cause a disabling pneumoconiosis, while noting that their 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 industrial hygiene survey with chest X-ray examinations of workers, plus summaries of five New York State compensation claim cases; includes a literature review of other studies
• Who was studied: 221 talc miners and mill workers from seven plants in St. Lawrence County, northern New York State, X-rayed in 1940. 28 men with positive lung findings were re-examined ten months later. A comparison group of 266 carpet factory workers had been examined previously by the authors.
• Exposure: Dust from fibrous talc of the asbestine variety found with tremolite, and reported by Gardner to include anthophyllite. Samples tested by the authors showed 1 per cent or less free silica. Dust counts ranged from 6 to 5,000 million particles per cubic foot in mining and from 20 to 215 million particles per cubic foot in milling.
• Main results:
  • Marked fibrosis was found in 32 of the 221 men examined in the 1940 survey (14.5 per cent).
  • All 32 fibrosis cases were among the 107 men who had worked in talc for ten years or longer, an incidence of 29.9 per cent for that group. No cases occurred in workers with less than ten years of exposure.
  • Of the 8 men who had worked 30 or more years in talc, 6 showed fibrosis (75 per cent).
  • Fibrosis was present in 2.5 per cent of all carpet workers and in 4.9 per cent of carpet workers aged 50 and older, compared with 51.5 per cent of talc workers aged 50 and older.
  • In a group of 18 men with marked fibrosis whose only significant dust exposure was talc, 15 were mill workers and 3 were miners. Thirteen of the 18 had one or more lung symptoms, and all 18 showed limited chest expansion.
  • Clinically significant tuberculosis, judged from X-ray appearance alone, was seen in 5 of the 221 workers (2.2 per cent), compared with an average of about 1.2 per cent in industrial groups. It was seen in 3 of the 18 talc-only fibrosis cases (16.6 per cent).
  • On X-rays, 14 of the 221 workers (6.3 per cent) showed what appeared to be deposits of opaque material on pleural surfaces. The authors called these "talc plaques" and described the material as unidentified. These workers' exposure in the talc industry ranged from 4 to 52 years. No symptoms or physical signs could be attributed to the deposits.
  • Six compensation claims for disability linked to talc dust had occurred in New York State; five of the six were fatal.
• The authors' conclusion: The authors concluded that tremolite talc is a silicate dust capable, like asbestos, of causing a disabling pneumoconiosis. They found evidence that tremolite talc fibrosis is associated with an increased susceptibility to tuberculosis, and stated that the dust requires engineering control.
• Limitations the authors state:
  • The authors stated that the number of cases presented was small, and they described the tuberculosis evidence as suggestive.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Talc and vermiculite, Tremolite.

Medical terms in this study, explained in our Lexicon: Tremolite, Talc, Anthophyllite, Million Particles per Cubic Foot (mppcf), Fibrosis, Dyspnea, Roentgen, Diaphragm.

Related studies

• Respiratory effects from industrial talc exposure among former mining workers — R.C. Loyola, A.P. Carneiro, et al. (2010)
• On talc, tremolite, and tergiversation — R. Reger, W.K. Morgan (1990)
• On talc, tremolite, and tergiversation. Ter-gi-ver-sate: 2: to use subterfuges — B.W. Case (1991)
• On talc, tremolite, and tergiversation — A.M. Langer, R.P. Nolan, et al. (1991)
• Health effects of tremolite. This official statement of the American Thoracic Society was adopted by the ATS Board of Directors, June 1990 — (1990)
• Commercial talc and talcosis — B. Weiss, E.A. Boettner (1967)

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