An unusual case of mixed-dust exposure involving a "noncommercial" asbestos

Our plain-English summary of An unusual case of mixed-dust exposure involving a "noncommercial" asbestos, by R.F. Dodson, J.L. Levin (Environmental Health Perspectives, 2001).

The study

• Authors: R.F. Dodson, J.L. Levin
• Journal: Environmental Health Perspectives
• Published: 2001;109(2):199-203
• Type of article: Case report
• Cited by: 14 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Our health center evaluated an individual for suspected pneumoconiosis, which had resulted from exposures in a foundry/metal reclamation facility. Appropriate consent forms were obtained for the procedures. Historically, individuals who work in foundries have been exposed to various types of dusts. The clinical findings in this case were consistent with silicosis with a suspicion of asbestos-induced changes as well. A sample from this individual, analyzed by electron microscopy, showed both classical and atypical ferruginous bodies. The uncoated fiber burden in this individual indicated an appreciable number of anthophyllite asbestos fibers. This finding, coupled with analysis of cores from ferruginous bodies and the presence of ferruginous bodies in areas of interstitial fibrosis, pathologically supported the diagnosis of asbestos-related disease. The unique factor associated with this case is that unlike in some settings in Finland where anthophyllite was mined and used commercially, this mineral fiber is not commonly found in commercially used asbestos products in the United States. Although the actual source of the asbestos exposure in this case is still being sought, it should be recognized that anthophyllite is a contaminant of many other minerals used in workplace environments, including foundries. The fiber burden indicates a unique type of exposure, differing from that usually construed as typical in occupational settings in the United States.

In plain English

This case report described a 53-year-old man who worked 32 years in an iron pipe foundry, the last 28 as a core maker in a high-dust environment. He worked without respiratory protection until the last few years. Lung biopsy pathology was first read as silicosis, later expanded to include asbestosis. The authors found ferruginous bodies consistent with asbestos bodies in areas of diffuse interstitial fibrosis. Digested lung tissue contained 5,280 classical ferruginous bodies per gram wet weight. Electron microscopy found 24 uncoated asbestos fibers, 23 anthophyllite and one tremolite. That equaled 641,667 fibers per gram wet weight. No uncoated commercial-type asbestos fibers were found. Crystalline silica was 8% of the particle burden, but the analyzed tissue did not fully represent the affected lung zones. No records showed that anthophyllite products were used at the foundry. The authors concluded it was reasonable that the exposure came from a product made mostly of a nonasbestos mineral with an appreciable anthophyllite component. A talc-containing material could be a suspect source, they wrote, but no specific product had been identified.

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: case report
• Who was studied: One 53-year-old man evaluated for suspected pneumoconiosis at The University of Texas Health Center at Tyler, first seen in early 1996
• Exposure: Mixed dust from 32 years in an iron pipe foundry, the last 28 as a core maker in a high-dust environment, mostly without respiratory protection; lung tissue showed anthophyllite asbestos (and one tremolite fiber) from a source not identified
• Main results:
  • The lung biopsy pathology first gave a diagnosis of silicosis, later expanded to include asbestosis
  • In this man's lung tissue sections, ferruginous bodies consistent with asbestos bodies were occasionally found in areas of diffuse interstitial fibrosis
  • Digested lung tissue contained classical ferruginous bodies at 5,280 per gram wet weight (43,560 per gram dry weight)
  • Electron microscopy found 24 uncoated amphibole asbestos fibers: 23 anthophyllite and one tremolite
  • The 24 asbestos fibers equaled 641,667 fibers per gram wet weight (5,293,750 per gram dry weight)
  • No uncoated fibers of the commercial types of asbestos were found in this case
  • Of the anthophyllite fibers, 69% were shorter than 5 µm; the remaining 31% averaged 14 µm in length
  • Crystalline silica made up 8% of the particle burden in the tissue analyzed
  • No records were found showing that products made with anthophyllite were used in the foundry where the man worked
• The authors' conclusion: The authors concluded it was reasonable that the man's exposure came from a product consisting mostly of a nonasbestos mineral with an appreciable anthophyllite component
• Limitations the authors state:
  • The tissue sent for electron microscopy was not fully representative of the lung zones that had clinically supported the silicosis diagnosis
  • The source of the anthophyllite was not identified; the authors wrote that a material containing talc could be suspect as a source, but no specific product had been identified

Topics

Medical terms in this study, explained in our Lexicon: Pneumoconiosis, Silicosis, Ferruginous Bodies, Fiber Burden, Anthophyllite, Interstitial Fibrosis, Mineral Fiber, Asbestos Exposure.

Related studies

• "Labrador lung": an unusual mixed dust pneumoconiosis — H.W. Edstrom, D.M. Rice (1982)
• Accumulation of mixed mineral dusts in the lungs of rats during chronic inhalation exposure — C.H. McMillan, A.D. Jones, et al. (1989)
• Mixed pneumoconiosis: silicosis, asbestosis, talcosis, and berylliosis — G.J. Mark, C.B. Monroe, et al. (1979)
• Tracheal carcinoma and mixed pneumoconiosis. A causal relationship? — D. Theegarten, S. Philippou, et al. (1995)
• Pulmonary mineral dust. A study of ninety patients by electron microscopy, electron microanalysis, and electron microdiffraction — J.P. Berry, P. Henoc, et al. (1976)
• Respiratory impairments due to dust exposure: a comparative study among workers exposed to silica, asbestos, and coalmine dust — X. Wang, E. Yano, et al. (1997)

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