On September 15, 2023, EPA received notification
from the Washington Department of Ecology (Ecology) via the National Response
Center (NRC) that gasoline and gasoline vapors had been detected in the
basement of a hotel in downtown Walla Walla above the lower explosive limits
(LEL), and the hotel was evacuated by the Walla Walla Fire Department.
Ecology’s Spill Response Program was working to confirm the source, suspected
to originate from a nearby gas station, as well as to determine the route of
migration, mitigate further leakage and recover spilled product. A tank at the
gas station demonstrated anomalies in fuel level indicators that signaled lost
product, and approximately 5,000 gallons of gasoline were transferred into an
alternate storage tank. A total of 2,475 gallons of gasoline mixed with water
were pumped from the sumps and vault of the hotel’s basement. No imminent
threat to surface water was identified at this time.
On September 18, 2023, gasoline vapor was
detected well above LELs in the basement of the United States Post Office,
located across the street from the impacted hotel, and the post office was
closed. On September 19, 2023, gasoline was found in storm drains around the
impacted area, and according to the city’s Public Works Department, these lead
into Mill Creek, a tributary of the Columbia River.
Two Ecology State
On-Scene Coordinators (SOSCs) have been deployed to the incident since Friday,
September 15, 2023. Ecology has been coordinating with other state and local
officials, including the Walla Walla Fire Department and Public Works
Department. Ecology requested EPA’s assistance.