State Water Resources Control Board

This letter describes the conditions under which underground storage tanks decommissioned before January 1, 1984 must comply with the closure requirements of Article 7 (Chapter 16, Title 23, California Code of Regulations). Section 2670(i) of this article states that tanks closed on-site by cleaning and filling with an inert solid before January 1, 1984 do not need to comply with the closure requirements. However, leaks from such tanks must be reported according to Article 5 and cleaned up according to Article 11.

The question remains as to which tanks decommissioned before January 1, 1984, without being cleaned and filled with an inert solid, need to comply with the closure requirements. The intent is to require compliance with the closure requirements if there are actual or potential leaks from such tanks. Therefore, if there is reasonable evidence that an actual leak has occurred or that a future leak may occur, then the closure requirements would apply. It will be deemed that there is reasonable evidence of an actual or potential leak when: 1) contamination that can be tied to the substance previously stored in the tank is found in nearby soil or water, or; 2) it is known that a hazardous substance remains in the tank which poses, or may pose a threat to human health or the environment if released. This section does not apply the closure requirements retroactively to every tank that was closed without being cleaned and filled with an inert solid before January 1, 1984.

The term "decomissioned" is used, rather than the term "closed", because the tanks in question did not necessarily comply with the closure requirements. A decommissioned tank is one that cannot have inputs or withdrawals, for one or more of the following reasons: 1) it has been filled with an inert solid; 2) its fill pipes have been sealed, or; 3) its piping has been removed. A tank that was not used on or after January 1, 1984 but could be used in the future meets the definition of an existing UST and is subject either to the operating or closure requirements of the law and regulations.

If you have any questions about this document, please contact Terry Brazell at 916-227-4404.

UST Program - Local Guidance (LG) 122