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Bioassay of coke oven coal tar carcinogenic activity, final report.
The carcinogenicity of coke oven coal tar was investigated. C3H-mice were treated dermally twice a week with 50 milligrams of various benzo(a)pyrene (50328) (BaP) solutions in toluene, whole coal tar containing different amounts of BaP, the light oil coal tar fraction, or coal tar with the light oil removed. The mice were examined periodically for tumors and skin lesions, and were killed for autopsy when carcinoma was diagnosed. The carcinogenicity of whole coal tar with 0.6 percent BaP and the light oil fraction removed was greater than that of a 0.6 percent BaP solution in toluene. The potency of the BaP solution accounted for 71 percent of the carcinogenic activity of the tar in the absence of the light oil fraction and for 77 percent of the activity when the light oil fraction was present. Dilution of BaP solutions with toluene reduced the potency of the compound more than similar dilution of coal tar solutions. Threshold BaP doses for animals given BaP in toluene and those given coal tar were 0.0006 and 0.00006 milligram, respectively. The authors suggest that coal tar contains additional carcinogens whose potency is masked in the presence of high BaP concentrations or that act as carcinogens.
NIOSH-Contract; Contract-099-73-0055; Laboratory-animals; Hydrocarbons; Polynuclear-hydrocarbons; Carcinogens; Carcinogenesis; Toxicology
Final Contract Report
NTIS Accession No.
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division