A Risk Assessment for Exposure to Grunerite Asbestos (Amosite) in an Iron Ore Mine

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 96; no. 7; pp. 3412 - 3419
• Main Authors: Nolan, R. P., Langer, A. M., Wilson, Richard
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 30.03.1999; National Acad Sciences; National Academy of Sciences; The National Academy of Sciences
• Series: Colloquium Paper
• Subjects: Amphiboles; Asbestos; Asbestos mining; Asbestos, Amosite - analysis; Asbestos, Amosite - toxicity; Asbestos, Crocidolite - analysis; Asbestos, Crocidolite - toxicity; Carcinogens - analysis; Cause of Death; Cigarette smoking; Colloquium Paper; Environmental Monitoring - methods; Ferrous minerals; Health risk assessment; Humans; Iron mining; Lung - chemistry; Lung neoplasms; Lungs; Mesothelioma; Minerals; Mining; Mortality; Occupational Exposure; Risk Assessment; United States; United States
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.96.7.3412

The potential for health risks to humans exposed to the asbestos minerals continues to be a public health concern. Although the production and use of the commercial amphibole asbestos minerals--grunerite (amosite) and riebeckite (crocidolite)--have been almost completely eliminated from world commerce, special opportunities for potentially significant exposures remain. Commercially viable deposits of grunerite asbestos are very rare, but it can occur as a gangue mineral in a limited part of a mine otherwise thought asbestos-free. This report describes such a situation, in which a very localized seam of grunerite asbestos was identified in an iron ore mine. The geological occurrence of the seam in the ore body is described, as well as the mineralogical character of the grunerite asbestos. The most relevant epidemiological studies of workers exposed to grunerite asbestos are used to gauge the hazards associated with the inhalation of this fibrous mineral. Both analytical transmission electron microscopy and phase-contrast optical microscopy were used to quantify the fibers present in the air during mining in the area with outcroppings of grunerite asbestos. Analytical transmission electron microscopy and continuous-scan x-ray diffraction were used to determine the type of asbestos fiber present. Knowing the level of the miner's exposures, we carried out a risk assessment by using a model developed for the Environmental Protection Agency.