“Waste oil” shall include, but not be limited to, crude oil or other hydrocarbons used or produced in the process of drilling for, developing, producing, or processing oil or gas from wells, oil retained on cuttings as a result of the use of oil-based drilling muds, or any residue from any oil storage facility on a producing lease or on a commercial disposal operation or pit. The term “waste oil” shall not include any refined hydrocarbons to which lead has been added.
Source: Corporation Commission, Oil and Gas Conservation, Oklahoma Administrative Code 165:10, February 2013. Regulations
Waste oil as mentioned in the third subsection, means used lubricants and similar oils (used in engines, gear boxes, hydraulic systems, transformers, switches etc.) that can no longer be used as originally intended.
Source: Guidelines Regarding the Activities Regulations, Norway, updated December 2012. Regulatory Guidance