What are the revisions being made to the headworks rule?
The promulgation of this rule finalizes the addition of benzene and 2-ethoxyethanol to the list of solvents whose mixtures are exempted from the definition of hazardous waste under RCRA, provided that certain conditions are met (benzene at or below 1 ppm with conditional management requirements and 2-ethoxyethanol at 25 ppm). In addition, scrubber waters derived from the incineration of the exempted solvents are included in the exemption. Facilities also now have the option to directly measure solvent chemical levels at the headworks of the wastewater treatment system to demonstrate compliance with the exemption in addition to the current requirement of performing mass balance calculations. Finally, this rule is broadening the scope of the de minimis exemption to include listed hazardous wastes (beyond discarded commercial chemical products) as well as eligible non-manufacturing facilities.
