The Environmental Protection Agency (EPA) classifies all used oil refined from crude oil and synthetic processes as contaminated, but makes distinctions between waste oil and used oil under the Resource, Conservation and Recovery Act (RCRA) guidelines.
Oil that is spilled and creates residue, or is generated as bottom waste in a storage tank, is considered waste oil.
If oil is mixed with hazardous chemicals (designated by the EPA) it falls under the RCRA used oil with hazardous waste mixture category. Handling of the oil depends on whether the used substance is flammable or reactive, or not.
Oil contaminated with solid materials can be cleaned and removed from the solid waste under EPA guidelines, freeing the solid materials from used oil regulations for disposal.
Polycholroinated byphenyls (PCBs) are used as coolant and dilutants with oils. Depending on the level of cross-contamination, these oils are subject to hazardous material disposal laws.
