UST Biodiesel


New UST Regulation for Alternative Compatibility

The variance for the provisional storage of biodiesel blends up to B20 has expired.  On June 1, 2012, new permanent California Underground Storage Tank (UST) regulations became effective to allow the storage of all biodiesel blends, including B100, in double-walled systems.  If the manufacturer of the UST containment system and related components does not have the required compatibility approvals from the appropriate independent testing organizations, under the new regulations, the owner or operator may submit a written affirmative statement of compatibility for the specific hazardous substance from the manufacturer(s).  The written affirmative statement of compatibility shall satisfy the requirements under CCR Title 23, Section 2631(b) and applies to all alternative fuels.  


The Materials Compatibility Letters previously submitted for the Variance Approval may not meet all of the requirements under the new regulations. 


Steps to assure UST compliance under new regulations:


  1. In 2015, the United States Environmental Protection Agency modified the federal UST regulations requiring UST system compatibility be confirmed through an independent laboratory, or through the use of an equipment or component manufacture compatibility approval. In response to these modifications to the federal UST regulations, national entities are now providing UST system compatibility documentation online. Web sites currently offering UST system compatibility information include the Petroleum Equipment Institute (PEI), and the Association of State and Territorial Solid Waste Management Officials Fuel Compatibility Tool web site.
  2. In addition, HMD requires that you determine functionality of the leak detection equipment used to monitor the alternative fuel stored.  The leak detection equipment must be listed in the SWRCB LG-113 approved listings and the manufacturer must indicate that the leak detection equipment can function with the identified alternative fuel stored. A separate list of acceptable biodiesel and ethanol leak detection equipment is also available.  
  3. Complete the Affirmative Statement of UST Compatibility with Hazardous Substance form and the UST Leak Detection Functionality with Hazardous Substance form  and submit to the County of San Diego Hazardous Materials Division if you wish to store biodiesel in your UST system(s).  Since the new regulations apply to all hazardous substances, please also include other alternative fuels you plan to store. The forms will be used to demonstrate compliance for compatibility under the new regulations.

Once HMD has determined that the UST system storing the alternative fuel(s) has met all the requirements of the new regulations for compatibility and leak detection functionality, a new UST Operating Permit will be issued. 

If you cannot provide any documentation that supports your UST system as having approved compatibility and leak detection equipment functionality, HMD will require the alternative fuel to be removed from the UST system immediately.

If you have any questions, please contact Cecilia Lewallen at: (619) 454-9915 or Veronica Archer at: (619) 454-9672.