Underground Storage Tank (UST) public record

We collect data on the sources and causes of underground storage tank (UST) releases in Washington.

The data displayed on this page is for federal fiscal year 2018 (October 1, 2017, to September 30, 2018).

General information as of January 2019:

  • Total number of active UST sites — 3,463 sites
  • Total number of active USTs — 8,927 tanks

Summary information for onsite inspections for federal fiscal year 2018: 1,164

  • Total number of UST site compliance inspections conducted: 1,164 inspections (1,164 by Ecology inspectors and 0 by Environmental Protection Agency [EPA] inspectors).
  • Percent of sites in compliance with the UST regulation on the day of inspection: 75 percent of sites in full compliance (a combined measure of release detection and release prevention requirements).

Note: Tank facility and onsite inspection information is based on USTs that are regulated under federal Subtitle I that satisfy the definition of UST in 40 CFR 280.12, except for those identified in 40 CFR 280.10(b) and (c) as excluded or deferred USTs. Emergency power generator USTs are included. Onsite compliance inspections measure significant operational compliance as defined by the EPA.

Summary information on UST contamination found (releases) for federal fiscal year 2018:

  • Number of confirmed releases: 23 sites with confirmed contamination.

Note: A majority of the 23 releases reported were found when old tanks were being removed and the soil sampled showed contamination. These are termed “legacy releases.” Legacy or historical releases are ones that may have occurred years ago and contamination was only found during this fiscal year. The release may have been discovered as the result of a site assessment, property redevelopment, or transaction involving tank removals.

This is in contrast to releases discovered due to leak detection, tank gauging systems, UST operator discoveries, unusual operating conditions, etc., as part of ongoing operation of the USTs. During tank removals and closures, it is difficult to determine the source or cause of the release from the sampling. The cause of a legacy release is more difficult to determine than a release that occurs and is detected in real time. Therefore, one will find a large percentage of the sources and causes of the releases identified in the chart below as “unknown.”

Confirmed releases found during fiscal year 2018

Release Source #
Dispenser 2
Piping 3
Tank 10
Unknown 12
Cause of Release #
Physical or mechanical damage 6
Unknown 17

Information posted January 3, 2019

We are required to report sources and causes of underground storage tank releases, according to the federal Energy Policy Act of 2005.