In a joint statement by the California Air Resources Board (ARB) and the State Water Resources Control Board, the agencies state that renewable diesel should be treated the same as conventional ARB diesel for all purposes, including storage in underground storage tanks (USTs). The statement was issued to clarify questions that have been raised regarding the ability of marketers and others to store renewable diesel in USTs.

There have also been questions about the compatibility of renewable diesel with leak detection systems used in USTs currently storing conventional ARB diesel. The agencies consider renewable diesel to be a “drop in” fuel that can be blended with conventional ARB diesel in any amount and used with existing infrastructure and diesel engines. Accordingly, renewable diesel that meets the requirements for conventional ARB diesel and ASTM D975-12a should be treated no differently than conventional ARB diesel that is legal for sale in California.

For this statement, conventional ARB diesel is petroleum-based diesel that meets specified aromatics, sulfur content, and lubricity standards, as well as ASTM International standard specification, ASTM D975-12a. Renewable diesel also meets ASTM D975-12a, but it is made from non-petroleum sources. Specifically, renewable diesel meets the definition of “hydrocarbon oil” and the physical and chemical properties specified in ASTM D975-12a.