I frequently see tanks and waste containers labeled as "waste oil." While it's great the generator is making an effort to clearly label their waste containers, usually they are mistaken in the type of label used. Used oil and waste oil are not interchangeable terms.
So what is the difference between USED OIL and WASTE OIL? Check out the brief summary below!
USED OIL
Regulations define "used oil" as any oil that has been refined from crude oil, or any synthetic oil that has been used and, as a result of that use, is contaminated by physical or chemical impurities.
Examples of used oil include: used motor oil, used hydraulic fluid, used electrical insulating oil, used transmission fluid, used compressor oils, used cutting oils, and used coolants. During normal use, impurities like dirt, metal scrapings, water, or chemicals can get mixed in with the oil. Eventually, the oil must be removed, replaced, and should be recycled.
WASTE OIL
Waste oil is a more generic term referring to oil that has been contaminated with substances that may or may not be hazardous. For example, if you had a drum of new oil product, and an employee mistakenly dumps in another chemical, this would render it unsuitable for its original purpose - it is now "waste oil." You would then need to perform a waste characterization to classify the new waste stream.
Simply put, waste oil is oil that has not been used, but it is found to be unsuitable (due to contamination) for its original intended purpose. Waste oil cannot be reused; often, it is diluted with water or some other chemical that makes it impure. Depending on the results of your waste characterization, you may end up with a hazardous or nonhazardous waste stream.
SOURCES: