ATSDR | Toxicological Profile for 3,3'-Dichlorobenzidine

3,3''-dichlorobenzidine is a synthetic chlorinated primary aromatic amine structurally similar to benzidine which is designated as a human carcinogen. It is used in the production of azo dyes and pigmentsin the textile, inks, plastics, rubber, and leather industries. In the United States, manufacturing use has significantly decreased since its classification as a possible human carcinogen, though its use in manufacturing processes abroad continues.

Among the general population, people living near production facilities or hazardous waste sites are at risk of 3,3'-dichlorobenzidine exposure through industrial wastewater effluents or groundwater contamination. 3,3'-Dichlorobenzidine has been detected over 6 km away from its source, and in wastewater effluent, can travel long distances when bound to sediment. In wastewater effluent, 3,3'-dichlorobenzidine has been measured at concentrations of ranging from non-detectable to 654 μg/L, and has been estimated at a median concentration <10 μg/L. Trace amount of 3,3'-dichlorobenzidine has also been detected in cosmetics that use colorants containing azo dyes in concentrations of 0.16-1.70 mg/kg; the highest concentration was observed in cosmetic skin care facial masks.