Mixtures of Used Oil & "Characteristic" Hazardous Wastes

The RCRA regulations allow used oil to be mixed with some hazardous substances, and still be handled under the regulations as used oil rather than as hazardous waste. However, the RCRA regulations are different for used oils that have been mixed with what are categorized as "characteristic" hazardous wastes.

The RCRA regulations identify different mixtures of used oil and "characteristic" waste by letter codes. The codes reflect the characteristic for which the hazardous material is listed. The codes are as follows:

• Letter code "I" - the hazardous waste is listed due to its ignitability
• Letter code "C" - the hazardous waste is listed due to its corrosivity
• Letter code "R" - the hazardous waste is listed due to its reactivity
• Letter code "T" - the hazardous waste is listed due to its toxicity

Under the RCRA regulations, used oil mixtures that contain one or more of these "characteristic" substances fall into one of the following categories:

• The resultant mixture no longer exhibits any hazardous waste characteristic. The mixture is considered to be "used oil."
• The resultant mixture exhibits one or more of the hazardous waste characteristics. The mixture is considered to be "hazardous waste."

Used oil that is classified as hazardous waste must be managed as hazardous waste, as regulated under the RCRA. However, there is one exception applicable to used oil that has been listed because it has been mixed with a contaminant that is itself listed solely for its ignitability characteristic. In this case, if the resultant mixture is not characteristic for ignitability, then the waste may be managed as used oil.

To learn more about RCRA visit our RCRA Hazardous Waste Safety Online Training web page.