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  • A polychlorinated biphenyl is a synthetic organic chemical compound of chlorine attached to biphenyl, which is a molecule composed of two benzene rings. There are 209 configurations of organochlorides with 1 to 10 chlorine atoms. The chemical formula for a PCB is C12H10-xClx. 130 of the different PCB arrangements and orientations are used commercially. Polychlorinated biphenyls 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 the U.S. Environmental Protection Agency, PCBs have been shown to cause cancer in animals, and there is also evidence that they can cause cancer in humans. A number of peer-reviewed health studies have shown an association between exposure to PCBs and non-Hodgkin Lymphoma, a frequently fatal form of cancer. However, other similar studies have found no such link. Studies of PCB workers have uniformally shown no statistically significant increased rates of deaths from non-Hodgkin Lymphoma. In 2013, The International Association for Research on Cancer determined that the evidence that PCBs cause non-Hodgkin Lymphoma is “limited” and “not consistent.” Wikipedia

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