Suspected Release Investigation, Confirmation of Releases (Prevention Program Activities), and Closure

There is a razor thin line of separation between UST prevention program and cleanup program activities associated with federally regulated UST systems.  This separation of activities occurs in the requirements pertaining to 40 CFR Part 280 subpart E – Release Reporting, Investigation, and Confirmation.  Initial response activities to a suspected release reside within the UST prevention program.  These activities include investigation of unusual operating conditions, determination of proper equipment functionality, investigation of alarms, and other such activities pertaining to normal operation of the UST system.  Cleanup program activities pickup at the point of investigation of soil, surface, subsurface water impacts, and other such activities pertaining to conditions external to the UST system. 

Warning signs of a release can be identified through inspection and monitoring, inventory control, and leak-detection technology. Release confirmation may solely involve prevention program activities (regarding the UST system operation), as well as cleanup program activities (involving conditions external to the UST system). Once the release is confirmed, notification to the appropriate government agency must follow particular state or tribal requirements. 

In some cases, emergency response actions must be taken immediately without waiting for government approval or oversight. Initial actions are all focused on protecting public health, safety, and the environment. Under most state regulations, the operator or owner has specific time frames to conduct initial response actions, submit reports, complete an initial site characterization, and conduct free product removal. It is important that LUST personnel reinforce these required targets in the event that an enforcement action becomes necessary.

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Release Sources

Identifying the specific portion of the tank or tank system that has caused a subsurface release is a critical first step. Common vulnerable areas include the bottoms of USTs (particularly underneath the manhole where gauging sticks are or were formerly used), associated piping, UST fill manholes, dispensing pumps, and areas known likely to have installation issues. Piping failures are especially common at UST junction points and when ground settlement in the vicinity of an UST varies from one end of a tank to the other.

Many states have conducted studies on the sources and causes of releases. Links to some of these studies are provided below, but there may be additional information available from other sources.

Warning Signs of a Release

Releases are detected in various ways. Leak detection equipment may signal a release, or unexpected water may be detected in a tank. There may be a spill identified while delivering fuel into an UST or dispensing fuel at the point of sale. Releases may also be identified during tank upgrades or replacements as these activities are also known to be common causes of releases.

Often, inventory control can alert the UST operator of a release, which may be discovered as a discrepancy in the inventory of fuel delivered versus the fuel dispensed from the UST. Newer UST systems have automatic tank gauging systems that can immediately identify a discrepancy using electronic measurement sensors and sound an alarm.

If a tank or UST system is being upgraded or replaced, field screening and sampling by a qualified professional may help to quickly identify a release and its specific cause. Experienced field oversight can also help limit the impact of a release on public health, safety, and the environment. The benefits to an UST owner of an immediate discovery of a release are reduced downtime and costs.

Release Confirmation

Confirming that a release has occurred from an UST should be done systematically. A first step is to determine if the UST system and monitoring equipment are operating correctly. Sensors that monitor releases may need to be checked to ensure that they are functioning properly. Another step may involve checking fuel delivery receipts to examine inventory. Once the equipment and inventory have been checked, a release can be confirmed by testing the tightness of the UST system using government and industry acceptable methods. Tank tightness is an indication of leaks, including very small or slow leaks.

Closure

The federal UST regulation provides requirements for out-of-service UST systems and closure of these systems. The requirements are more easily applicable to owners and operators deciding to close temporarily or permanently or to effect a change-in-service of their UST system. See Closing and Replacing UST systems for specific requirements.  See Closing and Replacing UST systems for specific requirements.  

Permanently Closed Pre 1988 UST systems

The federal UST regulation for out-of-service UST systems and closure requirements also applies to previously closed UST systems. 
When directed by the implementing agency, the owner and operator of an UST system permanently closed before December 22, 1988, must assess the excavation zone, and close the UST system in accordance with applicable federal UST requirements, if releases from the UST may, in the judgement of the implementing agency, pose a current or potential threat to human health and the environment. 

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Last updated on May 13, 2024