Polychlorinated biphenyl

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PCBs, or polychlorinated biphenyls, are a group of toxic chemicals that were widely used in carbonless copy paper and as coolants, insulators and lubricants. PCBs are of concern because they concentrate in the food chain resulting in health hazards to people, fish and wildlife. Congress banned the manufacture of new PCBs in 1976 and PCBs still in use are strictly regulated.