Polychlorinated biphenyl

Polychlorinated biphenyl (PCB), any of several compounds formed by substituting hydrogen (H) atoms in biphenyl (C₆H₅C₆H₅) with chlorine (C1) atoms. PCBs were once widely used in the manufacture of many products, including lubricants, paints, and adhesives. However, scientific studies have concluded that PCBs are a poisonous threat to the environment, killing wildlife and creating health problems for people. Their use has been banned in the United States.