The challenge of testing chemicals for potential carcinogenicity using multiple short-term assays: an analysis of a proposed test battery for hair dyes.

Recent reports of the association of hair dyes usage with increased bladder cancer risk in women with the slow NAT-2 acetylator phenotype have resulted both in attempts to identify the putative carcinogen as well as in devising batteries of tests that could be used to screen for such putative carcinogens in hair dye formulations, their intermediates and final products. Analytical studies have reported the presence of traces ( approximately 0.5 ppm) of the carcinogen 4-aminobiphenyl in some hair dye preparations.