Fatal asbestosis 50 years after brief high intensity exposure in a vermiculite expansion plant

Robert S. Wright, Jerrold L. Abraham, Philip Harber, Bryan R. Burnett, Peter Morris, Phil West

Research output: Contribution to journalArticlepeer-review

39 Scopus citations


The authors report the case of a 65-year-old accountant whose only asbestos exposure was during a summer job 50 years earlier in a California vermiculite expansion plant. Vermiculite is a silicate material that is useful in building and agriculture as a filler and insulating agent. He developed extensive fibrocalcific pleural plaques and end-stage pulmonary fibrosis, with rapidly progressive respiratory failure. Careful occupational and environmental history revealed no other source of asbestos exposure, and the initial clinical diagnosis was idiopathic pulmonary fibrosis; open lung biopsy shortly before his death confirmed asbestosis. Electron microscopic lung fiber burden analysis revealed over 8,000,000 asbestos fibers per gram dry lung, 68% of which were tremolite asbestos. Additional asbestiform fibers of composition not matching any of the standard asbestos varieties were also present at over 5,000,000 fibers per gram dry lung. Comparison analysis of a sample of Libby, Montana, vermiculite showed a similar mix of asbestiform fibers including tremolite asbestos. This case analysis raises several concerns: risks of vermiculite induced disease among former workers of the more than 200 expansion plants throughout the United States; health effects of brief but very high-intensity exposures to asbestos; and possible health effects in end-users of consumer products containing vermiculite.

Original languageEnglish (US)
Pages (from-to)1145-1149
Number of pages5
JournalAmerican journal of respiratory and critical care medicine
Issue number8
StatePublished - Apr 15 2002
Externally publishedYes


  • Asbestosis
  • Electron microscopy
  • Respiratory failure
  • Tremolite
  • Vermiculite

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine
  • Critical Care and Intensive Care Medicine


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