Talc is made up of pulverized, foliated, hydrous magnesium silicates from minerals with low crystalline silica content. Approximately 1.25 million short tons of talc were produced in the United States in 1989. The largest end uses of talc are in ceramics and paint; 5% is used in cosmetics. Concern over talc exposure is associated with the possible presence of asbestos as a contaminant. Estimates of environmental release of talc are not available. No information was available on the acute toxicity of talc. Subchronic inhalation exposure (3 to 12 mo) in rats resulted in pulmonary fibrosis that increased in severity as the exposure period increased. Chronic exposure by the intratracheal route in hamsters resulted in no observed fibrosis or granulomas. Limited data suggest that talc is not carcinogenic following inhalation exposure or intratracheal instillation in rats and hamsters. Similarly, no evidence of carcinogenicity was noted following intrapleural, intraperitoneal, or oral administration in rats. Several cross-sectional occupational studies of talc miners and millers showed no increase in mortality from lung cancer. For talc without asbestos contamination, the International Agency for Research on Cancer (IARC) has concluded that the available epidemiological and animal toxicity data are inadequate to demonstrate or refute the potential for carcinogenicity.

"EPA 600/8-91/217"--Cover. "March 1992"--Cover. "Office of Research and Development"--Cover. Includes bibliographical references (pages 4-1-4-8). "This document was prepared by Dynamac Corporation under contract no. 68-03-4140, for the Environmental Criteria and Assessment Office, Research Triangle Park, NC; Dennis J. Kotchmar, M.D. project officer"--Page ix.