[Formation of blastomogenic diphenylamino derivatives as a result of the metabolism of Direct azo dyes].

Under study was the urine from 22 workers being in long-term contact with direct azo dyes (direct black 3, direct diazo black, direct pure blue, direct light fast KU). Benzidine was found in the urine of 8 workers and dianisidine--in 3. Consequently, there occurs metabolic decomposition of the dyes concerned to free blastomogenic agents.