1,1'-Biphenyl, 2,2',3,5,5',6-hexachloro- 1,1'-Biphenyl, 2,3,5,6,2',5'-hexachloro- 2,2',3,5,5',6-HEXACHLOROBIPHENYL 2,2',3,5,5',6-Hcbp 2,3,5,6,2',5'-Hexachlorobiphenyl 52663-63-5 PCB 151