WALLA WALLA — State officials have identified the Chevron gas station at 7 E. Rose St. as the source of the gasoline that either seeped into the basement sumps or permeated the air inside three downtown Walla Walla buildings.

Tightness testing was conducted on gas tanks at two stations in downtown Walla Walla on Tuesday, Sept. 26, according to a city news release.

Tanks and lines for regular unleaded and premium unleaded fuel at the Chevron station and the Circle K station at 315 N. Second Ave. were tested for leaks.

Washington Department of Ecology spokesperson Stephanie May said abnormalities were found with the tank or line for premium unleaded fuel at the Chevron station.

Ecology placed red tags on the storage tanks at the Chevron station on Tuesday that prohibit the tanks from being refilled, May said.

She also said Chevron is also required to empty all the tanks within 24 hours and complete a site check within 30 days.

“What will likely happen is they’ll have to get those tanks dug up to see exactly where the leak is coming from,” she said.

The owner of the Chevron station has been cooperative throughout the investigation into the leak, according to the news release. May said Ecology records show the underground tanks at the station were installed in 1981.

The leak led to the closure of the Marcus Whitman Hotel and Conference Center, which is across the street from the Chevron station, after chemical odors permeated the building on Sept. 14 and gasoline was discovered in a basement sump. The downtown Walla Walla post office also closed its doors to the public because of high levels of volatile organic compounds in its basement.

A third building at 106 N. Second Ave., which is vacant, also was being monitored for chemicals on its property.

May said in an email that drilling efforts located gasoline contamination directly in front of the Marcus Whitman Hotel on North Second Avenue and close to the Chevron on North Second Avenue and East Rose Street.

The Walla Walla Fire Department passed the incident investigation off to Ecology on Tuesday, though the city will continue to provide support as needed, the release said.

May said the cleanup process is still being determined.

“Once the active spill is contained, then it will likely head over to our Toxics Cleanup Program, and that’s where they will determine exactly how to mitigate the spill and come up with a plan to clean up all of the contaminated soil,” she said.

Ecology will share updates about the investigation and cleanup process as information becomes available.

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