Stillwater Holdings Chevron

Page updated October 1, 2024.

After being identified as the source of the spill in September 2023, Stillwater Holdings hired an environmental consultant and contractor to investigate and help create a cleanup plan. Last November, the owner informed Ecology and local officials that they were working with their insurance company to fund and remove the leaking tank, and then clean up the contaminated soil. Stillwater Holdings’ insurance policy includes up to $1 million to cover potential spills and leaks. 

Ecology held a public comment period for the draft State Environmental Policy Act documents for the underground storage tank system replacement April 1–15, 2024. We responded to comments from four people, and we thank them for their input.  

In May, Stillwater Holdings told Ecology that they could pay for little or no more work, and that Ecology would need to take over. By law, Stillwater Holdings is responsible for the pollution, responding to the emergency, and cleaning up the contamination. 

Generally, Ecology does not use taxpayer funds to pay cleanup costs when the company has money available. Ecology is prepared to take over and fund the Walla Walla cleanup if needed because the spill poses significant risks to the community. We may step in when:

• The entity responsible exhausts all financial means of conducting the cleanup
• The entity is bankrupt
• The site has been abandoned

Mitigating potentially harmful vapors in the hotel and nearby building remains the highest priority. Because the leaking tank has been emptied, removing the underground tanks will be postponed.

We held a public comment period June 18 – August 16 for the Enforcement Order and Public Participation Plan. The order requires Stillwater Holdings to continue work to reduce harmful vapors and remove contaminated water from nearby buildings until a permanent treatment system is installed. You can learn more in the public notice we mailed to the surrounding community. We responded to comments from five people and thank them for their input. Based on concerns expressed about using state funding for cleanup, we amended the Enforcement Order to require a remedial investigation and feasibility study.

To ensure human health and the environment remain protected if the enforcement order is not followed, Ecology will continue operating vapor mitigation systems and removing contaminated sump water, and contract for longer term remedial options, such as a permanent sump water treatment system and contaminated soil removal. Ecology can also take legal action if the enforcement order is not being followed.

Concerns regarding a broken sewer line were provided via a letter from the owner of the 106 Building on August 15. Based on these concerns, the City of Walla Walla completed a dye test August 20, to check if there was a break in the sewer line. The city found that water discharging from the sink is discharging to Rose Ave., not 2nd Ave., indicating the system is functioning as it should.

Between August 16 and 21, Ecology sampled indoor air in the 106 Building, basement sumps in the 106 Building and the Marcus Whitman Hotel, and all site groundwater wells. The 106 Building sampling results showed initial indoor air was safe for adults working an 8-hour shift, but not for children or adults occupying the building for longer than a normal work shift. Groundwater sampling analysis showed results above cleanup levels. Ecology’s next round of groundwater sampling will likely occur during November or December 2024.

On September 5, 2024, Stillwater Holdings had five soil samples collected on their property while removing some old product lines and fuel pumps. Sample results showed contaminated soil near the southern fuel canopy at 300 milligrams per kilogram (mg/kg), and cleanup is required at 30 mg/kg. Stillwater Holdings’ consultant, Aspect, interpreted the contamination as highly weathered gasoline likely from the historical release.

Local, state, and federal agencies, along with third-party contractors, have deemed the area safe for residents and visitors with protection measures and air quality monitoring in place. Testing of Walla Walla's municipal water and wastewater systems and nearby Mill Creek has shown no evidence of contamination.

On September 14, 2023, the Marcus Whitman Hotel was evacuated due to volatile organic vapors entering the building, also known as vapor intrusion. The Walla Walla Fire Department called in Ecology’s Spill Response Team to help assess the situation and identify the source. 

Testing identified potentially harmful vapors and gasoline in the basement, and in two nearby buildings. The buildings were ventilated to eliminate the risk of an explosion, and the buildings’ drainage systems, also known as sumps, were pumped to reduce vapor concentrations. 

An investigation found that gasoline from a Stillwater Holdings’ underground tank had leaked and was pooling in adjacent buildings’ sumps. The leaking tank was taken out of service and has been emptied.