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r _ ... lazdrd Evaluation System dr information Service ❑ 2151 Berkeley Way Berkeley, CG 44704 ❑ MwS484138 Polychlorinated DIPhenyls PCBs (polychlorinated biphenyls) have been widely used since the 1930x, because of their excellent electrical. and temperature4nsulvting abilities. For many years, PCBs were considered to be al- most non -tont, since there were very few reports of illness even among industrial workers who were exposed to fairly large amounts. In 1978, the Environmental Protection Agency (EPA) began to im- pose bans on PCB manufacturing and sales and on most PCB uses. Nevertheless, it is still possible for workers to be exposed to PCBs, either through servicing and handling equipment that contains PCBs, or as a result of leaks, spills, and furs. This fact sheet answers some of the most frequently ked questions about PCBs. . Why did the EPA ban PCBs? The toxic effects of PCBs fust drew attention in 1968, when over 1200 people in Japan were poisoned byeating food cooked in oil that was heavily contaminmed with PCBs and other chemicals. This caused illnesses which became known as Yusho (rice oil) disease. Soon afterward, studies showed that PCBs cause cancer in test animals. Therefore, it is considered likely that PCBs can cause cancer in humans But why were PCBs banned, while many other chemicals which also cause cancer in test animals were not? PCBs remain in the environment for a long time, because they do not break down Also, their elimination from the body is very slow, so that levels in body tissues may increase with time. Thus, PCBs build up in the food chain, so that the fish and animals we eat could contain significant amounts. In short, the thing that sets PCBs apart from �eher equally toxic industrial chemicals is the ability of PCBs to persist in the environment and accumulate in the body and the food chain. . Where are PCBs found? PCBs were used mainly in electrical trans- formers and capaators, heat transfer systems, and hydraulic systems. They were also used in inks and carbonless copy paper and for a variety of other purposes, but the EPA ban now prohibits almost all of these other uses. Nowadays, PCBs are found mostly in transformers and capacitors. These may be contained in industrial equipment (such as welding equipment), medical equipment (such as X-ray machine), and household appliances (such as refrigerators and microwave ovens). The ballasts of some fluorescent light fixtures contain PCBs. During normal operation of a fluorescent light, the PCBs are entirely enclosed, and you cannot be exposed to them. However, when the capacitor wears out, sometimes it may burn or break and leak PCBs.