Spokane International Airport PFAS site

The order requires the City of Spokane and Spokane County to complete a remedial investigation, feasibility study, and potential interim actions, which can occur at any time during the cleanup process. The investigation will determine the full extent of per- and polyfluoroalkyl substances (PFAS) and other contamination in soil and groundwater, and the feasibility study will evaluate cleanup options. The order includes a scope of work and schedule for completing the investigation and study, excluding any work Spokane International Airport (SIA) will do or has already done. Interim actions could include cleaning up areas of high concern or providing safe drinking water if off-property impacts are found. The Public Participation Plan describes how you can be involved during the cleanup process. Because SIA is already in progress on the work, it continues during this public comment period.

Learn more

• Review the Agreed Order and updated Public Participation Plan.
• Visit our SIA PFAS cleanup site page.

Next steps

Ecology will consider and respond to all comments we receive during this public comment period. We will post our response to comments document on our SIA PFAS webpage, send the document to people who submitted comments, and email the West Plains PFAS updates email list.

Site background

We issued an Enforcement Order to SIA in March 2024, which requires them to do the same work as this Agreed Order. In August 2025, we named the City of Spokane and Spokane County as parties responsible for cleanup because the airport is jointly owned by the two local governments. The city, county, and SIA are responsible for investigation and cleanup costs.