what are pcbs used for?
<answer> They used in the past, mainly in electrical equipment, but which were banned at the end of the 1970s in many countries because of environmental concerns. <context> Context-Polychlorinated biphenyls (PCBs) are a group of man-made compounds that were widely used in the past, mainly in electrical equipment, but which were banned at the end of the 1970s in many countries because of environmental concerns.