Leaking Underground Storage Tanks in Idaho
Petroleum releases from leaking underground storage tanks (LUSTs) pose numerous potential threats to human health and the environment. Petroleum can seep into and through the soil to the water table. At the water table, these liquids can accumulate as a pool on top of the water because most substances in underground storage tanks (USTs) (e.g., petroleum) are less dense than water. Here the chemicals can dissolve into and contaminate ground water and surface water. In Idaho, ground water supplies about 95% of the population's drinking water, so keeping it clean is a high priority. In addition, vapors from petroleum releases can be a health and safety concern within buildings and around construction workers.
DEQ's LUST program provides for the oversight and cleanup of petroleum releases from state-regulated USTs. This oversight and cleanup process is guided by the following rules:
- Idaho's Water Quality Standards (IDAPA 58.01.02.851 and 852)
- Idaho's Rules Regulating Underground Storage Tank Systems (IDAPA 58.01.07.200)
- Standards and Procedures for Application of Risk Based Corrective Action at Petroleum Release Sites (IDAPA 58.01.24)
This process requires owners and operators of USTs to report suspected releases, investigate suspected releases, and determine if a confirmed release requires cleanup. In addition, the requirements describe when spills and overfills from an UST system must be reported and cleaned up. These rules also apply to petroleum releases from unregulated tanks.
Cleanup of LUSTs
Once a release has been confirmed, the responsible party must continue to evaluate the site to determine the extent of contamination and whether remediation is necessary. Determination of the need for remediation is guided by the Standards and Procedures for Application of Risk Based Corrective Action at Petroleum Release Sites (IDAPA 58.01.24). These rules were established in April 2009 and revised in March 2012 by the Idaho Legislature. The rules and accompanying guidance, Risk Evaluation Manual for Petroleum Releases, outline standards and procedures to determine whether and what risk-based corrective action measures should be applied to property where petroleum releases have occurred. The guidance was released in August 2012. The rules and guidance do not apply to previously closed sites, and DEQ does not require any additional evaluation of petroleum release sites previously granted closure unless a new petroleum release occurs.
Depending on site-specific conditions, remediation measures at a petroleum release site may include activity and use limitations implemented through a legal instrument called an environmental covenant.