Cleanup Action in Buckley

The project is a complex environmental remediation effort centered on a long-standing fueling station and convenience store in Buckley, Washington. The site has been in operation since the 1980s and includes aging underground storage tanks (USTs) that have contributed to subsurface contamination. What makes this project particularly challenging is the presence of commingled petroleum hydrocarbons and chlorinated solvents—specifically gasoline-range organics (GRO), diesel-range organics (DRO), and compounds like tetrachloroethylene (PCE) and trichloroethylene (TCE). These contaminants have impacted soil, groundwater, and vapor pathways, raising significant environmental and regulatory concerns.

Initial investigations revealed that the contamination likely originated from both the UST system and a former septic tank. Groundwater monitoring wells showed elevated levels of both petroleum and chlorinated compounds, indicating a complex plume with multiple sources. This dual-contaminant scenario complicates remediation, as petroleum hydrocarbons and chlorinated solvents behave differently in the subsurface and require distinct treatment approaches.

The project team has proposed a remediation strategy. The project is being conducted under the oversight of the Washington State Department of Ecology through the Voluntary Cleanup Program (VCP). As of mid-2025, the project team submitted an updated interim action plan to Ecology. The plan proposes injecting a strong oxidant to treat comminingled petroleum hydrocarbons and chlorinated solvents. This in situ chemical oxidation (ISCO) approach is designed to agreesively reduct contaminant mass and mobility in groundwater, adressing both fuel- and solvent-related impacts in a signle treatment phase.