One of the plants I service here in Houston is in the business of disposing of HAZMAT waste. They have all sorts of separators and ovens they process waste. PCBs are burned there.
Apparently, these incinerators are some very heavy duty stuff, back in the early 90's we had a PCB amnesty here, I was reading at the time a book on how these PCB's are disposed of, the temperature that they incinerate these materials at, is something quite phenomenal.
We were sending a LOT of PCB filled gear (or the oil itself) to France.
Unfortunately, there are still a lot of devices here still in use here that contain PCB's and are only being found when they break down and have to be replaced (like fluorescent lighting ballasts).
