Under the used oil management rules at 40 CFR 279.22(d), upon detection of a release of used oil to the environment (e.g. soil) that is not subject to the underground storage tank requirements of 40 CFR 280, generators of used oil must (among other requirements) “clean up and manage properly the released used oil and other materials.”

In order to properly dispose of the dirt and absorbent materials that were used to clean up the used oil spill, you need to determine whether these materials would be considered hazardous waste or solid (nonhazardous) wastes which is based on whether the used oil itself was a hazardous waste. In order to make that determination, you will find it helpful to review EPA’s Used Oil Determination Flowchart on enviro.blr.com.

Although you note that there are no free liquids, based on EPA’s “mixture rule” and “derived-from” rule found in the regulations at 40 CFR 261.3(a)(2)(iv) and 40 CFR 261.3(c)(2)(i), the absorbent material used to clean up the oil spill would be considered a hazardous waste if the used oil is determined to be a hazardous waste. These rules, and the exemptions to them, are explained in the regulatory analysis section of Hazardous Waste Determination on enviro.blr.com.