Polychlorinated biphenyls (PCBs) are a group of human-made chemicals. PCBs were widely used in building materials and electrical products in the past. Caulk, paint, glues, plastics, fluorescent lighting ballasts, transformers and capacitors are examples of products that may contain PCBs.
The U.S. Environmental Protection Agency (EPA) banned manufacturing and certain uses of PCBs in 1979. Buildings constructed or renovated between 1950 and 1979 may have building materials and electrical products that contain PCBs.