Polychlorinated biphenyls (PCB)
Polychlorinated biphenyls (PCB’s) were widely used as dielectric and coolant fluids, for example in electrical apparatus, cutting fluids for machining operations, carbon paper and in heat transfer fluids. Due to PCBs’ environmental toxicity and classification as a persistent organic pollutant, PCB production was banned by the United States Congress in 1979 and by the Stockholm Convention on Persistent Organic Pollutants in 2001.
According to theU.S. Environmental Protection Agency (EPA), PCBs cause cancer in animals and are probable human carcinogens.
Concerns about the toxicity of PCBs are largely based on compounds within this group that share a structural similarity and toxic mode of action with dioxin. Toxic effects such as endocrine disruption and neurotoxicity are also associated with other compounds within the group. The maximum allowable contaminant level in drinking water in the United States is set at zero, but due to water treatment technologies, a level of 0.5 parts per billion is the de facto level.