Oil wastes and wastes of liquid fuels covered by Chapter 13 of the List of Wastes, including hydraulic oils, engine oils, insulating oils, bilge oils, and lubricating oils. Most waste oils are classified as Absolute Hazardous entries, meaning they are always hazardous regardless of testing. Common codes include 13 01 (hydraulic oils), 13 02 (engine and lubricating oils), and 13 03 (insulating oils). Waste oils containing PCBs or chlorinated compounds require special handling.