The general population may be exposed to benzidine through contact with leather products, clothing, and toys containing benzidine or benzidine-based paints. The food dyes tartrazine and sunset yellow contain trace amounts of benzidine (within nanograms per gram of food). The production and use of benzidine in the production of paints has been recorded in some developing countries. Exposure to benzidine through ingestion is unlikely, but other impurities in synthetic dyes may be metabolized to benzidine after ingestion. Benzidine causes bladder cancer. Its urinary metabolites are benzidine and benzidine conjugates (monoacetylbenzidine).