Northside Landfill, also known as Indian Trails Landfill, sits in Spokane, Washington. It operated as a waste disposal site and was placed on the EPA's National Priorities List on June 10, 1986. The site has since completed cleanup and was deleted from that list in 2020. One business currently operates on-site, and the City plans to continue running the landfill until its remaining waste cells reach capacity.
The main contamination problem was tetrachloroethylene, or PCE, a dry-cleaning solvent. About 300 tons of solvent filters and sludges were spread through an unlined landfill, allowing PCE to soak into the groundwater and travel downstream. PCE can harm the nervous system, liver, kidneys, and reproductive system, and may raise cancer risk. Other contaminants found in the groundwater include trans-1,2-dichloroethene, trichloroethane, and trichloroethene. In 1983, PCE turned up in nearby residential wells, though concentrations stayed below the EPA's drinking water standard of 5 parts per billion. Affected residents received bottled water in 1983 and were later connected to the municipal water supply.
Cleanup work started with a remedial investigation in March 1985. Three unlined landfill cells were closed to new waste in 1991, and a groundwater extraction and treatment system was finished in 1993. The original cleanup plan, selected in September 1989, called for water supply replacement, treatment of contaminated material, drainage and erosion controls, an engineered cap, institutional controls, and permitted surface water discharge. A 2009 update added air stripping technology to pull contaminants from water and allowed for infiltration basin or trench discharge as an option. An Environmental Covenant recorded in 2011 prohibits activities that could damage the remedy and restricts groundwater use. Zoning rules also prevent incompatible uses like residential development.
By 2020, all groundwater cleanup levels had been achieved. The EPA confirmed no unacceptable human health or environmental risks remain. Human exposure is under control, groundwater migration is stabilized, and physical construction of the cleanup is complete. The site was deleted from the National Priorities List on September 30, 2020. Even so, five-year reviews, institutional controls, and operations and maintenance activities continue. The most recent five-year review was completed in July 2022, and the next is estimated for July through September 2027.
Community members with questions can contact the EPA Community Involvement Coordinator or the Spokane Regional Health District. The health district is at 1101 W. College Ave., Spokane, WA 99201. Site records are available through EPA Region 10's Superfund Record Center at 1200 6th Avenue, Suite 155, Seattle, WA, reachable at 206-553-4494 or R10_SF_Records_Center@epa.gov.
