A concise assessment of the risks to human health and the environment posed by exposure to biphenyl. Biphenyl is an aromatic hydrocarbon used as an intermediate in the production of several compounds, including crop protection products and plastics, as a heat transfer medium in heating fluids, as a dyestuff carrier for textiles and copying paper, as a solvent in pharmaceutical products, and in the treatment of citrus fruits. Biphenyl has been detected in all environmental compartments as a result of its release from industrial activities and residential and industrial heating devices, and its presence in motor vehicle exhaust gases and tobacco smoke. The report cites evidence that the general population may be exposed via inhalation of polluted air, from the use of biphenyl-containing creosotes in wood preservation, and via the ingestion of treated citrus fruits. Exposure via drinking-water was judged to be limited. Based on the few studies available, the report concludes that biphenyl is unlikely to pose a significant risk to the environment. Studies of kinetics and metabolism indicate that the compound is rapidly absorbed, rapidly metabolized and rapidly eliminated in urine.