Formation of PCDF and PCDD in electrical discharges

The formation of polychlorinated dibenzofurans (PCDF) and dibenzo-dioxins (PCDD) in electrical discharges in liquids containing polychlorinated biphenyls (PCBs) is examined. Little or no formation of these products was found in high-energy short-duration breakdowns or arcs in air-saturated trichlorobenzene (TCB), mixtures of TCB and PCB, or mineral oils containing small amounts of PCB. Low-energy partial discharges could not be sustained in air-saturated liquids. It is concluded that the formation of PCDF and PCDD within electrical equipment does no appear likely.<>