Chronic animal inhalation study of short (5 micrometers) asbestos fibers.
NIOSH 1980 May; :447-469
The chronic effects of inhalation of short chrysotile asbestos (1332214) fibers were studied in rats and monkeys. Sprague-Dawley- rats and cynomolgus-monkeys were exposed in an inhalation chamber for 7 hours a day, 5 days a week, for 18 months to less than 1 milligram asbestos fiber per cubic meter of air. The ratio of the number of fibers less than 5 microns in length to the number greater than 5 microns was 265 to 1. Rats were killed at 1, 3, 6, 12, and 18 months after exposure began, and tissues were examined histopathologically and by scanning electron and light microscopy. Lung tissue showed little or no reaction to inhaled asbestos. Light microscopy did not reveal asbestos fibers in lung tissues, but electron microscopy detected fibers in alveolar macrophages. No tissue tests had been conducted on monkeys at the time of this report since none had been sacrificed or had died.
Asbestos-dust; Fibrous-bodies; Laboratory-animals; Dust-inhalation; Histology; Dust-exposure; Pulmonary-system-disorders
Kraybill-HF; Blackwood-IC; Freas-NB
Proceedings of the First NCI/EPA/NIOSH Collaborative Workshop: Progress on Joint Environmental and Occupational Cancer Studies, May 6-8, 1980, Rockville, Maryland, H. F. Kraybill, I. C. Blackwood, and N. B. Freas, Eds. National Cancer Institute, Environmental Protection Agency, National Institute for Occupational Safety and Health
International Research and Development Corporation, Mattawan, Michigan 49071