During a compliance audit a few years ago, we were advised to change the labeling of oil drums ready for disposal from “waste oil” to “used oil”. Although it is easy to confuse the two, used oil and waste oil are not interchangeable terms.
“Used oil” is a precise regulatory term. The EPA defines "used oil" as any petroleum or synthetic oil that has been used, and as a result of such use is contaminated by physical or chemical properties. “Waste oil" is a more generic term for oil that has been contaminated with substances that may or may not be hazardous.
EPA regulations for the management of used oil are defined in 40 CFR Part 279, and 279.22 defines regulations for used oil storage, including regulations for labeling. EPA’s used oil management standards are a set of “good housekeeping” requirements that encourage used oil handlers to recycle used oil instead of disposing of it. Used oil can be collected, refined and recycled, and used again—for the same job or a completely different task.