Asbestos dust: a study on the pathogenetic mechanism.
Gross-P; Harley-RA Jr.
Industrial Health Foundation, Inc., Pittsburgh, Pennsylvania 1972 Dec; :1-20
Samples of crocidolite (12001284), amosite (12172735), and Canadian chrysotile (12001295) were prepared by five different methods for intratracheal injection to rats. A fairly high mortality was noted in the first 6 months, generally from pneumonia. Of the 1537 rats injected intratracheally one to four times, only 727 rats survived 6 months. The total dosage ranged from 1.75 to 21 milligrams. The results of the study indicated that the intratracheal injection of the three most important asbestos (1332214) dusts into rats caused no induction of cancer. It made no difference to the outcome whether these dusts were natural or had been modified by the addition or subtraction of trace metals, or whether the dusts had been heated. A significant lessening of the fibrogenicity of asbestos dust was caused by heating the dusts. These findings suggested that the theory that trace metals assist in the pathogenic potential of asbestos dust must be abandoned. The failure of lung cancers to develop in this study as they had in previous studies could not be explained. The authors conclude that the pathogenicity of chrysotile asbestos may not be attributable to its fibrous shaped particles, its magnesium-silicate molecule, or to its crystalline character.
NIOSH-Grant; Pulmonary-system-disorders; Laboratory-animals; Lung-cancer; Carcinogens; Mineral-dusts; Asbestos-dust
None Industrial Hlth Fdn, Inc 5231 Centre Avenue Pittsburgh, PA 15232
12001-28-4; 12172-73-5; 12001-29-5; 1332-21-4
Final Grant Report
NTIS Accession No.
Industrial Health Foundation, Inc., Pittsburgh, Pennsylvania
Industrial Health Foundation, Pittsburgh, Pennsylvania