Mica Landfill, south of Spokane

In May 2026, we visited the site and found the monitoring wells, landfill cap, leachate ponds, and flare system in good condition. We also reviewed all groundwater monitoring data and found contamination is generally remaining at consistent levels in the same locations. Groundwater monitoring will continue to track cleanup progress and ensure remaining contamination does not move off-site. The deed restrictions prevent exposure to remaining contamination.

Moving forward, we recommend:

• Working with the lab to find a test method that can find vinyl chloride at levels below state standards
• Testing for PFAS in monitoring wells near the landfill boundary
• Submitting groundwater data into our Environmental Information Management system

Learn more

• Review the draft periodic review.
• Visit our Mica Landfill cleanup site page.

Next steps

Ecology will review all comments received during the comment period and update the periodic review if needed. If no significant changes are made, the periodic revi​​ew will become final. If significant changes are made, an additional public comment period will be held. We will hold a public meeting if 10 or more people request one.​​​

Site history

The site was a landfill operated by local governments from 1972 to 1991. The landfill received about 65,000 tons of waste per year in the form of residential and municipal solid waste, dewatered sewage treatment plant sludge, demolition debris, and industrial wastes.

About periodic reviews

We review conditions at sites where some contamination remains about every five years, to make sure the cleanup is still effective. This is the fourth review for this site.