RCRA sorts hazardous waste generators into three categories by what they generate in a calendar month — and everything follows from the category: how long waste can sit on site, what training and planning are required, and how much regulatory attention you’ve invited. Most mid-size plants have never formally run the math.
No more than 100 kg (about 220 lbs) of hazardous waste and no more than 1 kg of acute hazardous waste in a calendar month. Lightest obligations — but a hard cap: accumulate past 1,000 kg on site and the exemption ends. Note that some states, California among them, don’t adopt the federal VSQG category at all.
More than 100 kg but less than 1,000 kg per month. Accumulation clock: 180 days — 270 if your disposal facility is over 200 miles away — with a 6,000 kg cap on site, container dating, weekly inspections, and emergency coordination duties.
1,000 kg or more per month, or more than 1 kg of acute hazardous waste. The 90-day clock, no quantity cap, and the full program: contingency planning, personnel training, biennial reporting, and the compliance posture regulators expect of it.
Three of them, reliably. First: status is determined monthly, not annually — a plant can be an SQG eleven months a year and an LQG the month it cleans out the paint room, and that month carries LQG obligations unless the episodic generation provisions are properly used. Second: the clock starts at accumulation, and every container needs its date — undated drums are the single most common waste finding, and a drum that sits past your limit converts you, legally, into an unpermitted storage facility, which is among the serious RCRA violations. Third: acute waste plays by its own math — more than 1 kg in a month means LQG management for that waste regardless of your ordinary tonnage.
Chasing a lower category by honest waste minimization — solvent recycling, product substitution, better segregation of non-hazardous streams — is legitimate cost reduction: lower disposal costs, lighter obligations, less exposure. Chasing it by wishful counting is how enforcement cases start. The determination deserves the same rigor as your chemical inventory: someone fluent in the waste codes, counting every stream including the ones that don’t look like “waste” — off-spec product, spent solvents in parts washers, contaminated absorbents, that drum of mystery liquid behind maintenance. States run their own authorized programs and several are stricter than the federal floor, so verify your category and clocks against your state’s rules.
Up to 55 gallons of hazardous waste (with tighter limits for acute waste) may accumulate at or near the point of generation, under operator control, before the main clock starts — which is why the drum next to the machine is legal and the same drum in the corner of the warehouse is a finding. Satellite rules are the difference between a workable shop floor and a violation, and training the floor on that difference is cheaper than learning it in an inspection.
Very Small Quantity Generator (up to 100 kg/month), Small Quantity Generator (100–1,000 kg/month), and Large Quantity Generator (1,000 kg or more, or over 1 kg of acute hazardous waste) — determined each calendar month under RCRA, with states able to impose stricter schemes.
LQGs: 90 days. SQGs: 180 days, or 270 when shipping over 200 miles, with a 6,000 kg on-site cap. VSQGs face no federal clock but a 1,000 kg accumulation cap. Exceeding your limit means operating as an unpermitted storage facility.
Yes — it’s determined by each calendar month’s generation. A cleanout or project month can push a facility into a higher category with that category’s duties, unless the episodic generation exemption is properly invoked and documented.
Up to 55 gallons of hazardous waste accumulated at or near the point of generation under the control of the operator, before container dating and the main accumulation clock apply — subject to marking, container condition, and prompt transfer rules once limits are reached.
If the answer involves the phrase “we’ve always been,” the determination is overdue. One walk-through with the waste codes settles it.
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