Source assessment of hexachlorobenzene from the organic chemical manufacturing industry.

The Office of Solid Waste of the US Environmental Protection Agency determines the hazards of wastes produced by the organic chemical manufacturing industry. Based on these determinations, regulations have been laid down for many wastes under the Resource Conservation and Recovery Act. Additional wastes from this industry will be considered for regulation following further study and evaluation. Among the wastes under study are hexachlorobenzene (HCB)-containing wastes. Although HCB is no longer manufactured in the USA, the US Environmental Protection Agency has estimated that approximately 4130 t are generated annually as a by-product in the production of chlorinated organics and pesticides. Of this total, about 77% (3178 t) is generated from the production of three chlorinated solvents: tetrachloroethylene, carbon tetrachloride and trichloroethylene. All wastewater containing HCB is treated biologically in surface impoundments, resulting in HCB accumulation in the biological sludge. Disposal methods for HCB-containing sludges and distillation bottoms are incineration and landfilling, with 81% (3345 t) being incinerated and 19% (785 t) going to landfills.