Moses Lake Port Pumphouse 1

Jet fuel has contaminated the shallow aquifer around Pumphouse 1 at the Grant County International Airport. All drinking water wells in the vicinity are drilled into the deep aquifer, which is not affected, and it appears that groundwater contamination has not spread further than about 500 feet from Pumphouse 1.

In January 2019, Ecology identified the Port of Moses Lake and Exxon Mobil as potentially liable persons (PLPs), who will be financially responsible for site investigation and cleanup of petroleum (jet fuel) in soil and groundwater. The Port of Moses Lake is a PLP because they own the site, and Exxon Mobil is a PLP because they formerly leased the site. Ecology invited the PLPs to negotiate an agreed order requiring them to complete a remedial investigation on November 17, 2022.

Next, the PLPs will conduct a remedial investigation to determine the nature, extent, and magnitude of pollution at the site. When this is complete, they will use the information to develop cleanup options.

As an independent cleanup action, Exxon installed a system to recover jet fuel from groundwater wells in 2015. Every three months, the system is maintained and the rate of pumping is assessed. Approximately 300 gallons of liquid petroleum has been recovered as of January 2018.

The site is at the Grant County International Airport, previously Larson Air Force Base. Former Exxon-leased facilities historically used to dispense jet fuel at the site include:

• Pumping equipment and dispensers located inside the Pumphouse 1 building.
• Six underground storage tanks (USTs) ranging in size from 2,000 to 50,000 gallons used to store jet fuel, located east of, and partially underneath, the Pumphouse 1 building.
• Underground piping connecting the Pumphouse 1 USTs to two above-ground storage tanks located south of the airport, as well as to Pumphouse 2 and 3 and associated fueling hydrants located east-northeast of Pumphouse 1.

In 1992, petroleum contamination (jet fuel) at levels requiring cleanup was found in soil during a site assessment. Then in January 1993, liquid petroleum was found in one site groundwater well located approximately 100 feet southeast of the Pumphouse 1 building. Subsequently, liquid petroleum or petroleum products dissolved in groundwater at levels requiring cleanup have been found in 14 site groundwater wells. Based on available data, it appears that groundwater contamination has not spread further than about 500 feet from the site.

Until a full investigation is completed, how jet fuel specifically got in soil and groundwater is unknown. It could have been due to leaking tanks or piping, overfilling tanks, and/or spills during refueling.

The U.S. Environmental Protection Agency (EPA) is cleaning up soil and groundwater contamination from hazardous chemicals related to former Larson Air Force Base operations and industrial activities. While both the EPA's and Ecology's cleanups are located at the Grant County International Airport, they are separate and are focused on different contaminants from different sources. 

For more information on EPA's work, please see their Moses Lake Wellfield Contamination Superfund Site website.