4-Aminobiphenyl was formerly used as a rubber antioxidant and in the manufacture of azo dyes. Due to its carcinogenicity 4-aminobiphenyl is no longer produced commercially. It is found in tobacco smoke.

Uses 

4-Aminobiphenyl is not produced commercially. However, it is used in research as a cancer-causing agent.

Toxicity  

4-Aminobiphenylmay have been released into the environment during its production and use as a rubber antioxidant and dye intermediate; however, sources suggest that it was no longer in significant production by the early 1970s. 4-Aminobiphenyl is easily oxidizable and probably undergoes photolysis but there is little actual data on these processes. If released on land it is expected to adsorb moderately to soil, probably binding to humic materials, and undergo redox reactions. If released to surface water, it is expected to adsorb to sediment, and probably undergo photolysis and oxidation. It may be degraded by oxidation by alkoxy radicals, which are photochemically produced in eutrophic waters, with an estimated half-life of 14 days. 4-Aminobiphenyl is biodegradable and biodegradation may well occur in both soil and water but there are no rates available for soil or surface waters. It has a low potential for bioconcentration. In the atmosphere, degradation should occur due to direct photolysis, oxidation by ambient oxygen, and photochemically produced hydroxyl radicals (estimated half-life 6–7 h in the vapor phase).

Environmental Fate

4-Aminobiphenyl is one of a number of chemicals that cause methemoglobinemia, or conversion of hemoglobin to methemoglobin, which reduces the ability of the blood to carry oxygen to the tissues. In addition, the active metabolite is believed to produce cancer through its reaction with cellular DNA. In animal studies, the observed incidence of 4-aminobiphenyl adducts with bladder epithelium DNA correlated well with the observed bladder tumor incidence.