Electrical PCB accidents, an update

In 1978 it was reported that pyrolysis of technical PCB mixtures as well as defined PCB congeners resulted in a conversion into PCDFs. The optimal yields could be as high as 10%. Since some of the PCDF congeners are known to be highly toxic the authors issued a warning to planned and accidental burning of PCBs. Buser and Rappe also discussed four mechanisms by which PCBs are transformed into PCDFs: 1) elimination of two O-chlorine atoms; 2) elimination of HCl; 3) elimination of HCl followed by a 2,3-migration; 4) elimination of two O-hydrogen atoms.