Epidermal carcinogenesis studies of synthetic fossil fuel materials in mice

Skin tumor response in mice to solvent fractions of heavy distillate (HD) from a solvent-refined coal (SRC-II) process indicated that the basic tar and neutral tar were the most carcinogenically potent fractions. Assays of another SRC-II coal liquid that had been fractionally distilled indicated that the carcinogenicity of this material for mouse skin is due to that portion boiling above 371 degrees C (700 degrees F), and that the carcinogenic potency of the material increased with boiling point. Samples of the 399-427 degrees C (750-800 degrees F) distillate were nitrosated to destroy primary aromatic amines and were chemically fractionated to assess the carcinogenicity of chemical class fractions of these complex mixtures. Data from these assays indicated that neutral polycyclic aromatic hydrocarbons (PAH) and nitrogen-containing polycyclic aromatic compounds (NPAC) both contribute to the carcinogenicity of this distillate.