In this guide 3 min read
Used oil is not automatically handled the same way as hazardous waste. Federal rules give recycled used oil its own management standards under 40 CFR Part 279.
These rules apply to businesses that generate used oil, including auto repair shops, fleets, dealerships and industrial facilities. People changing oil in their own vehicles at home are excluded from these federal business requirements (40 CFR 279.20(a)(1)).
Key takeaways
- Recycled used oil follows its own rules in 40 CFR Part 279, not the hazardous waste rules.
- Mixing in a listed hazardous waste makes the whole mixture hazardous waste.
- Over 1,000 ppm of total halogens, the oil is presumed mixed unless you can show it was not.
- Used oil thrown away instead of recycled must be managed as hazardous waste if it shows a hazardous characteristic.
The short answer on used oil and hazardous waste
Used oil that will be recycled is generally managed under the federal used oil standards in 40 CFR Part 279.
EPA states that recycled used oil remains subject to these standards whether or not the oil exhibits a hazardous waste characteristic.
There are important exceptions. Hazardous waste rules can come into play when:
- Used oil is mixed with hazardous waste.
- Used oil contains more than 1,000 parts per million of total halogens and the presumption that it was mixed with hazardous waste cannot be rebutted.
- Used oil is disposed of instead of recycled and exhibits a hazardous waste characteristic.
What counts as used oil
Federal regulations define used oil as oil refined from crude oil, or synthetic oil, that has been used and contaminated by physical or chemical impurities as a result of that use (40 CFR 279.1).
For a shop or fleet, that includes motor oil drained from engines as well as other qualifying oils that have been used in equipment.
What happens when used oil is mixed with hazardous waste
Mixing used oil with the wrong material can change how the entire mixture must be managed.
If used oil is mixed with a hazardous waste specifically listed by EPAEPA publishes lists of specific hazardous wastes in 40 CFR Part 261. Spent solvents used for degreasing, such as some chlorinated cleaners, are on those lists., the mixture is regulated as hazardous waste (40 CFR 279.10(b)(1)(i)).
If it is mixed with a waste that is hazardous because of a characteristic such as ignitabilityWaste can be hazardous because of what it does: catches fire easily (ignitability), corrodes, reacts or is toxic (40 CFR Part 261, Subpart C)., the mixture is regulated as hazardous waste when the resulting mixture exhibits that characteristic (40 CFR 279.10(b)(2)).
That is why EPA advises businesses not to mix used oil with other materials.
The 1,000 ppm halogen rule
Halogens include chlorine, which can be found in some solvents and degreasers.
When used oil contains more than 1,000 parts per million of total halogens, federal rules presume it has been mixed with a listed halogenated hazardous waste (40 CFR 279.10(b)(1)(ii)).
Total halogens in used oil
That presumption can be rebutted with documentation showing that the oil was not mixed with hazardous waste.
For shops and fleets, the practical rule is simple: keep solvents, degreasers and other chemicals out of the used oil tank.
What if used oil is thrown away instead of recycled?
The Part 279 used oil standards apply to used oil that will be recycled.
If used oil is disposed of or sent for disposal instead, it must be managed as hazardous waste when it exhibits a hazardous waste characteristic.
EPA encourages recycling used oil, including through re-refining.
How businesses keep used oil under the Part 279 rules
For most businesses, proper used oil management comes down to a few basic practices:
- Store used oil in tanks or containers (40 CFR 279.12(a)).
- Keep tanks and containers in good condition and free of visible leaks (40 CFR 279.22(b)).
- Label them "Used Oil" (40 CFR 279.22(c)).
- Stop, contain and clean up leaks or spills (40 CFR 279.22(d)).
- Keep solvents, chemicals and other waste streams out of the used oil (40 CFR 279.10(b)).
- Use a transporter with an EPA identification number when the oil leaves your site (40 CFR 279.24).
Can it go in the used oil tank?
Pick an item, then choose where it goes.
Used oil tank
- Engine oilMotor oil drained from engines is used oil.
- Hydraulic oilUsed hydraulic oil counts as used oil.
- Gear oilUsed gear oil counts as used oil.
- Transmission fluidUsed transmission fluid counts as used oil.
- Oil drained from used filtersOil drained from used oil filters goes in the used oil tank.
Keep out
- Brake cleanerChlorinated brake cleaners raise the halogen level. Over 1,000 ppm, the whole tank is presumed mixed with hazardous waste.
- AntifreezeGive spent antifreeze its own container. UES can often take it on the same visit.
- Solvents and degreasersMixed with used oil, certain solvents make the whole mixture hazardous waste (40 CFR 279.10(b)).
- Parts washer fluidParts washer solvent is its own waste stream. Keep it separate.
All sorted. Print the sign below and post it by your tank.
State requirements can be stricter than the federal standards, so businesses should also check the rules where they operate.
What goes in the used oil tank: shop sign
A one-page sign for the wall by your tank. Goes in, keep out, and why it matters.
Download the signHow UES handles used oil and hazardous waste
UES collects used oil from commercial and industrial customers in 28 states and records the quantity and service date at every pickup.
Much of the oil we collect goes to our re-refinery in Peachtree City, Georgia, where it is processed into recovered base oil for new lubricants.
If your business also generates hazardous waste, our hazardous and special waste division handles that material separately.
Request service through our used oil pickup page, find your state on our locations page, or call 800.988.7977. We reply the same business day.
UES locations serve Georgia, Alabama, Tennessee, New Jersey, Arizona and 23 more states.
Questions businesses ask
Is used motor oil a hazardous waste?
Not automatically. Used oil that will be recycled is generally managed under the used oil standards in 40 CFR Part 279.
What is the 1,000 ppm halogen rule?
Used oil with more than 1,000 parts per million of total halogens is presumed to have been mixed with a listed halogenated hazardous waste. The presumption can be rebutted with documentation.
Can solvents or degreasers go in the used oil tank?
No. Keep solvents, degreasers and other chemicals out of the used oil tank. Mixing them in can make the whole tank hazardous waste.
Does UES handle hazardous waste too?
Yes. Our hazardous and special waste division handles that material separately from used oil.
Written by Universal Environmental Services. Reviewed by Scott Eddings, VP of Operations. Checked against 40 CFR Part 279 on October 6, 2026.
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