Carbon/Graphite Fibers: Environmental Exposures And Potential Health Implications.
NIOSH 1980 Dec:19 pages
Environmental and health implications of carbon (7440440) and graphite (7782425) fibers are reviewed. These fibers are made commercially from any carbonaceous, fibrous raw material that pyrolyzes to a char and leaves a high carbon residue. Carbon fibers are pyrolyzed at 1200 degrees-C and consist of amorphous carbon; graphite fibers are carbon fibers that have been heat treated to temperatures of 200 to 2700 degrees, resulting in a crystalline fiber structure. NASA tests of carbon and graphite fibers released during simulated aircraft burns are summarized. A small percentage of fibers with diameters less than 3.5 micrometers (microm) and length greater than 10microm were released. Concentrations were on the order of 0.1 fibers per cubic centimeter. Animal toxicity studies in which guinea-pigs were exposed to airborne carbon fibers indicated the presence of fibers 10microm in diameter and 100microm in length or 1.0 to 2.5microm in diameter and less than 15microm in length in the lungs. No tumors were found. The authors recommend that well designed animal toxicity studies be performed with carbon and graphite fibers on the order of 3.5microm in diameter or less and 10microm in length.
NIOSH-Author; Asbestos-fibers; Environmental-pollution; Occupational-exposure; Animal-studies; Combustion-products; Pyrolysis-products; Aerospace-industry; Toxic-materials;
NTIS Accession No.
Division of Surveillance, Hazard Evaluations and Field Studies, NIOSH, U.S. Department of Health and Human Services, Cincinnati, Ohio, 19 pages, 24 references