The Palermo Well Field Superfund site sits in Tumwater, Washington, where two industrial chemicals contaminated soil and groundwater. Trichloroethylene, or TCE, came from Washington Department of Transportation facilities. Tetrachloroethylene, or PCE, came from the Southgate Dry Cleaners. When the City of Tumwater found TCE in three drinking water supply wells in 1993, it pulled those wells from service immediately. The site was added to the National Priorities List in April 1997.
Both TCE and PCE are human-made chemicals with serious health effects. TCE can damage the central nervous system, liver, kidneys, and immune system, can affect fetal heart development during pregnancy, and is classified by EPA as a cancer-causing chemical. PCE can affect the central nervous system, liver, kidneys, blood, and immune system. Both chemicals appear in groundwater and soil. PCE is also found in air, surface water, and soil gas. A key concern is vapor intrusion, where contaminant vapors move from groundwater up into homes or businesses. EPA is monitoring residences for indoor vapor exposure and evaluating whether that monitoring should expand to businesses.
EPA has taken several cleanup steps over the years. In 1998, a soil vapor extraction system was installed at the dry cleaners to pull PCE out of the soil, running through summer 2000. In 1999, two air stripping towers were built at the Palermo Wellfield to treat contaminated groundwater. A subdrain system west of nearby residences was also installed to lower the groundwater table and reduce the risk of vapors collecting in crawlspaces. Physical construction of these measures was completed in February 2001. In November 2024, EPA issued a Record of Decision Amendment for Operable Unit 2, the area covering the dry cleaners source zone. The updated plan adds soil vapor extraction for contaminated soil and reactive barriers to capture and reduce contaminants in groundwater. Construction of this new work is scheduled to begin in Fall 2025.
EPA's 2023 Five-Year Review found the existing remedy is protective in the short term but that additional actions are needed for long-term protection. EPA currently has insufficient data to confirm that human exposures are under control or that groundwater contamination has stabilized. Cleanup goals have not yet been fully achieved across the entire site.
Community members can get involved in several ways. EPA updated the site's Community Involvement Plan in 2023 with input from residents, businesses, local governments, and community organizations. A community open house was scheduled for February 1, 2025, at Palermo Pocket Park in Tumwater, where EPA, the Washington Department of Transportation, and the City of Tumwater planned to share updates. Site documents are available for public review at the Tumwater Timberland Library at 7023 New Market Street, Tumwater, WA 98501, reachable at 360-943-7790. For questions, contact the EPA staff assigned to the site.
