Jenna Ladd| July 11, 2017 In the largest study of its kind, UI researchers have detected polychlorinated biphenyls (PCBs) in six schools throughout the midwest. Polychlorinated biphenyls (PCBs) are a class of manmade organic chemicals that were heavily used in construction and industry from 1929 until they were banned in 1979. PCBs are now known to…