ISTR that form of dioxin is a by-product of using diphenyl (with impurities) in high-voltage transformers. When the transformer burns, explodes or degrades, they used to dump the remaining liquid (the part that didn't leak, spill or vaporize) in a pit, lake, river, bay or ocean. Nowadays they partially burn it, which usually allows some poly-aromatic hydrocarbons to be broadcast into the atmosphere. Then they dump the char (which still contains large amounts of poly-aromatic hydrocarbons) into a pit. The people who work at those facilities tend to die of cancer at age 30-40.