2,2',3,3',4,5',6,6'-Octachlorobiphenyl

2,2',3,3',4,5',6,6'-Octachlorobiphenyl is one of 209 polychlorinated biphenyls (PCBs), a group of synthetic organic compounds with 1-10 chlorine atoms attached to biphenyl. PCBs were manufactured as commercial mixtures but were banned in the 1970s because they were found to bioaccumulate and cause harmful health effects; they do not break down readily and are still found in the environment.