Air monitoring tests continue around WW hotel, U.S. Post Office basement now closed

By on Monday, September 18th, 2023 in Columbia Basin News More Top Stories

News release from city of Walla Walla

WALLA WALLA – The Walla Walla Fire Department has been performing scheduled air monitoring tests at businesses around the Marcus Whitman Hotel. The only place that has shown a slightly elevated level of volatile organic compounds (VOCs) is the basement of the U.S. Post Office. Post Office staff closed the basement and are working with Clean Harbors to create a ventilation plan to remove the VOCs from that space. There have been no elevated levels of VOCs detected in other parts of the Post Office, which continue to be open for employees and the public.

Coordinating with Department of Ecology crews, Clean Harbors has resumed pumping operations at the hotel. They are beginning with the basement stormwater vault area that was emptied on Sunday but appeared to have backfilled with some water overnight. The source of the water can’t be determined due to debris in the vault. The crew will pump out the vault again and continue to monitor it.

Next, the crew will drain a stormwater vault and associated system outside the hotel as a precautionary measure.

After that, the crew will return to the stormwater sump in the hotel basement that also was drained on Sunday. Water has reappeared in the sump, as well, possibly due to the resettling of mud in the base of the sump.Crews will remove the water and mud, then inspect the sump to determine whether it has a floor, which could indicate how the water is flowing in. They will reassess based on what they see.

Air-quality monitors running continuously outside of the Marcus Whitman hotel have detected zero concentrations of VOCs or LELs (lower explosive limits) on the street during pumping operations. 

The source of the gasoline found in the hotel basement has not been positively identified. DOE will work with a contractor to perform a precision tank tightness test on the 10,000 gallon tank that is suspected to be the source. The testing is expected to happen this afternoon.

DOE staff took samples from the gasoline found in the hotel basement and from the gas station. They are taking the samples to a laboratory today for fingerprint analysis that can determine whether the samples are of the same type of fuel. This will not conclusively indicate whether the gas came from the Chevron station, but it could provide another clue as investigators work to determine the source of the gasoline.

There is no evidence gasoline has entered Mill Creek. Clean Harbors placed absorbent material in all the storm drains in the area as a precautionary measure to prevent any potential contamination of city waterways.

Potential contamination in the ground around the hotel is unknown at this point. If additional contamination is suspected once the hotel basement is cleared, a DOE team will assess the situation and coordinate a longer-term investigation.

The hotel remains closed during these operations. WWFD officials have created a list of standards and requirements that need to be met and approved by various agencies to ensure the safety of staff and guests before reopening. There are currently too many variables to set a firm timeline, but all parties involved in this ongoing response are focused on helping the hotel and the other businesses in its building reopen as soon as is safely possible.

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.

Photo via city of Walla Walla