Generators of hazardous waste know that their generator class status depends on the amount (volume) and type of hazardous waste that they generate in a calendar month. They also know that under the federal RCRA rules, and most state variations of the RCRA rules, that there are three classes of generators: large quantity generators (LQGs), small quantity generators (SQGs), and conditionally small quantity generators (CESQGs)."

They know all this because their legal responsibilities in connection with the management of their generated hazardous waste hinge on their class of generator – with LQGs having more regulatory obligations than SQGs, and CESQGs having far fewer legal responsibilities than either LQGs or SQGs.  Because most generators are consistently the same class of generator month after month, they understand the obligations that go along with their generator class. They may be less clear, however, as to their responsibilities when the occasional situation arises that finds them to have generated more (or less) hazardous waste than their generator class allows. They are what EPA calls an “episodic generator.”

What is an Episodic Generator?

This is not actually a generator class, but a term EPA uses to describe a generator who may periodically exceed (or fall) below its normal generation limits in any given calendar month. According to EPA, if the amount of hazardous waste generated in a given calendar month places the generator in a different category, the generator is an “episodic generator” responsible for complying with all applicable requirements of the generator category for all waste generated during that calendar month. For example, if an SQG produces 300 kg of hazardous waste in May, that waste must be managed in accordance with the SQG regulations; if the same generator produces 1,500 kg of hazardous waste in June, that waste must be managed in accordance with the LQG regulations.

Generators often wonder if once they’ve become a different category of generator due to an episodic event, they remain in that category for the rest of the calendar year, especially if they became a larger generator. Regarding the described example, EPA would say that the generator must comply with all applicable LQG requirements for hazardous wastes generated in June for as long as that waste remains on-site. If the generator reverts back to SQG status in July, the generator must continue to manage the hazardous waste generated during the month it became an LQG according to all applicable LQG requirements. (What requirements that situation involves, in practice, will be determined by the state environmental regulatory agency.) Hazardous waste generated during any months the generator was an SQG can be managed under SQG requirements.

What Circumstances Create an Episodic Generator?

Episodic generators include those who only occasionally generate hazardous waste, those who occasionally fluctuate between the three hazardous waste generator categories, and those who routinely change generator categories at least 1 month a year. Instances where a generator may fall into another generator category unexpectedly, or as the result of a one-time occurrence, include: lab clean outs; off-specification product inventory clean outs; tank cleaning; underground storage tank removals; spills of hazardous waste or product that become hazardous waste when spilled; and those hazardous wastes (e.g., contaminated media and debris) generated from conducting remediation-related activities.

Generators that have had an episodic generation should contact their state environmental regulatory agency and inquire as to the requirements for episodic generators, such as notifying the agency of the change in generator class, requesting an EPA ID number (if the generator does not already have one), or filing an annual report (if required by the state) for all or part of the calendar year.

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