Polychlorinated Biphenyls (PCBs)

Black and white chemical structure of PCB 153

Structure of PCB 153, a polychlorinated biphenyl

CAS Number: various

PCBs were once used in a wide variety of industrial applications, including as insulating fluid in electrical equipment and as plasticizers. PCBs were banned in the late 1970s but are still in some old equipment and products. They can also be unintentionally formed during the production of certain pigments and dyes. PCBs have spread through the environment and take a long time to break down.

 Also see Hydroxy-PCBs.