The public health implications of polychlorinated biphenyls (PCBs) in the environment.

Polychlorinated biphenyls (PCBs) were widely used in various industrial applications. Research confirmed that some PCB congeners degrade slowly in the environment and can build up in the food chain. Poisoning episodes in Asia were initially attributed to PCB-contaminated oil, although subsequent analysis suggested that thermal degradation products of PCBs were responsible for the observed toxicity. Commercial production of PCBs in the United States was banned in 1979. Several agencies have categorized PCBs as animal carcinogens; however, studies of workers exposed to high doses of PCBs have not demonstrated an increased cancer risk. Health effects attributable to PCBs include skin and eye irritation. There is no reliable evidence that PCBs in the environment result in either "endocrine disruption" or intellectual deterioration in children exposed in utero. Because PCB exposures from environmental sources do not pose a significant health risk, little benefit to public health can result from continued remediation of PCB sources.