Mutagenic activity of chemicals previously tested for carcinogenicity in the National Cancer Institute bioassay program.

Twenty-six chemicals treated in long-term carcinogenicity bioassays were tested for mutagenicity in the Salmonella/microsome plate assay. Of the eight chemical reported as being noncarcinogenic in animals, five were not mutagenic and three induced a mutagenic response. Thirteen chemicals were carcinogenic in either rats, mice or both species. Ten of these were positive in the mutagenicity assay, and three were negative. Four chemicals were suspect as far as the carcinogenicity results were concerned, and three were negative. The results obtained in vivo with one compound were inconclusive, and the mutagenicity results were negative.