Failure to induce mutations in Chinese hamster V79 cells and WB rat liver cells by the polybrominated biphenyls, Firemaster BP-6, 2,2',4,4',5,5'-hexabromobiphenyl, 3,3',4,4',5,5'-hexabromobiphenyl, and 3,3',4,4'-tetrabromobiphenyl.

Firemaster BP-6 (FM), a mixture of polybrominated biphenyls (PBB), and the congeners 2,2',4,4',5,5'-hexabromobiphenyl (2,4,5-HBB), 3,3',4,4',5,5'-hexabromobiphenyl (3,4,5-HBB), and 3,3',4,4'-tetrabromobiphenyl (3,4-TBB) were tested for their ability to induce mutations in mammalian cells in culture. A rat liver microsome-mediated (S 15) Chinese hamster V79 cell mutation assay was used to test the mutagenicity of PBB and 3,4-TBB. V79 cells and WB rat liver cells were used to detect the mutagenicity of 2,4,5-HBB and 3,4,5-HBB. No mutagenic effects were detected at the dose levels tested. The possibility that these compounds promote liver neoplasms via a nongenotoxic mechanism is discussed.