What are Polychlorinated Biphenyls (PCBs)?

Polychlorinated Biphenyls (PCBs) are a group of synthetic organic chemicals that can cause a number of different harmful effects. There are no known natural sources of PCBs in the environment. PCBs are either oily liquids or solids and are colorless to light yellow. Some PCBs are volatile and may exist as a vapor in air. PCBs have no known smell or taste. PCBs enter the environment as mixtures containing a variety of individual chlorinated biphenyl components, known as congeners, as well as impurities. The health effects of environmental mixtures of PCBs are difficult to evaluate. Some commercial PCB mixtures are known in the United States by their industrial trade name, Aroclor. Because they don't burn easily and are good insulating materials, PCBs were used widely as coolants and lubricants in transformers, capacitors, and other electrical equipment.

The manufacture of PCBs stopped in the United States in August 1977 because there was evidence that PCBs build up in the environment and may cause harmful effects. Consumer products that may contain PCBs include old fluorescent lighting fixtures, electrical devices or appliances containing PCB capacitors made before PCB use was stopped, old microscope oil, and old hydraulic oil.

Source: Agency for Toxic Substance and Disease Registry, Center for Disease Control (CDC) (n.d.)