Suspected source of gasoline contamination at Walla Walla hotel discovered

By on Sunday, September 17th, 2023 in Columbia Basin News More Top Stories

News release from city of Walla Walla

UPDATE as of Sunday, Sept. 17 at 6:30 p.m.:

Crews from Clean Harbors and Washington State Department of Ecology were on site all day today. The continuous ventilation Clean Harbors has in place continues to keep volatile organic compounds at low concentrations and LELs (lower explosive limits) at zero.

Assisted by DOE, Clean Harbors performed one pumping operation in the morning and one in the afternoon. Both operations were successful — contaminated material was removed from the hotel basement’s sump and vault, and there were no notable spikes in VOCs in the surrounding area. 

The pumping operations ended in the mid-afternoon and could resume following a Monday morning meeting of stakeholders.

Walla Walla Police Department personnel assisted with area security to ensure pedestrian and vehicle traffic would not interfere with the ongoing work being performed. 

Walla Walla Fire Department crews continued to monitor the area surrounding the hotel and report no adverse readings were reported.

The response team appreciates the flexibility of the community as we learn more about the situation and adjust our approach to changing conditions.

City staff will continue to provide these updates on the City website ( as the situation changes.

Original post:

WALLA WALLA – The contractor, Clean Harbors, found what appears to be pure gasoline present in a 10 foot-deep sump in the basement of the Marcus Whitman Hotel and Conference Center. The gasoline is suspected to have come from a 10,000 gallon tank, containing regular unleaded fuel, belonging to the Chevron gas station across the street at 7 E. Rose St. There is no pipeline connecting gas station equipment to the hotel.

There is no indication any gasoline has entered Walla Walla’s underground utility infrastructure or waterways.

Over Saturday night, a contractor pumped out the premium unleaded gasoline from a different tank at the Chevron location, then pumped the regular unleaded from the suspected tank into the tank that had contained the premium fuel. 

The suspected tank is now virtually empty and will be tightness tested to detect any leaks once a contractor can be secured to perform the testing. A timeline for this testing has not been identified at this point.

This morning (Sunday), a Clean Harbors crew is preparing to begin pumping the gasoline out of the hotel’s basement sump. They will use pneumatic pumping equipment to eliminate the possibility of the fuel or fumes igniting. The gasoline will be transferred to an intermediate bulk container (IBC) totes and transported outside to a frac truck parked adjacent to the hotel on Second Avenue, and from there transferred to a frac tank located on the northern portion of the hotel property.

A safety plan has been established for the operation. During this work, air-quality monitors in hotel and outside on the street level will be working to detect concentrations of volatile organic compounds (VOCs) and an LEL (lower explosive limit). Readings in the basement are currently virtually zero due to the ventilation system installed by Clean Harbors.

During the pumping, if the monitors detect VOCs or LELs, an alarm will sound and the crew members will immediately stop pumping and remove themselves from the area. Pumping will then resume once readings indicate the levels are reduced to nonhazardous levels.

A crew from Walla Walla Fire Department is on the scene to provide backup if necessary. Washington State Department of Ecology staff are present to monitor the situation and provide technical assistance as needed.

Crews will monitor what happens within the sump as the material is removed, and will determine their next steps based on their observations and the data collected. There is no estimated timeline for how long this pumping operation will last.

2nd Avenue between Cherry and Rose streets is closed to vehicles and pedestrians, as is Sumach Street between Rose and Colville Street. Customers may use the sidewalk on the south side of Sumach to access the Post Office.

There is no immediate risk to the community, but WWFD and Walla Walla Police Department personnel will be ensuring no one enters this closed area. If you don’t need to visit the Post Office or Chevron store, you should avoid the area to limit distractions to the workers and emergency personnel.

The response team appreciates the flexibility of the community as we learn more about the situation and adjust our approach to changing conditions.

The city will provide updates on the City website ( as the situation changes.

Photo via city of Walla Walla