The role of mononitrochlorobenzene as a contaminant in dinitrochlorobenzene.

Dinitrochlorobenzene (DNCB) has been purported to possess potential mutagenic and carcinogenic hazards. This potential hazard may be due to contamination of DNCB with known carcinogenic precursors, mononitrochlorobenzenes. Three samples of commercially available DNCB were analyzed for the presence of such mononitrochlorobenzenes, which were absent in all samples tested. The implications of product contamination with mutagenic and/or carcinogenic impurities may be important for both in vitro Ames microbial assays and potential carcinogenic exposure in human therapy.