Queen City Farms sits 2.5 miles north of Maple Valley, Washington. From 1955 to 1964, liquid industrial hazardous waste was dumped into three onsite ponds and burned off as they filled. EPA began investigating in 1979 and added the site to the National Priorities List (NPL) in 1984. NPL listing means EPA determined the site needed formal cleanup under the Superfund program.
More than 100 contaminants have been identified across soil, sludge, groundwater, and surface water. These include heavy metals such as lead, mercury, arsenic, cadmium, and chromium, as well as volatile organic compounds like trichloroethene, benzene, and vinyl chloride. Polycyclic aromatic hydrocarbons, chlorinated benzenes and phenols, phthalates, and pesticides are also present. Some contaminants were found in multiple media, pointing to widespread distribution across the property.
Cleanup has progressed in stages. The most contaminated soils were excavated and removed. Remaining soils were consolidated and capped, with a barrier wall that is regularly inspected. In 2020, EPA confirmed all soil cleanup goals were met and removed soils from the NPL. A groundwater extraction and treatment system built in 2015 supplements natural recovery. Groundwater monitoring will continue until cleanup levels are reached. Land use restrictions prevent residential, agricultural, and groundwater uses that could interfere with the ongoing work.
EPA's most recent five-year review, completed in September 2023, found that the remedy currently protects human health and the environment. Human exposure is under control, and groundwater contamination is stabilized within its original area. Risks from contaminated sediments have been resolved. The site has achieved ready-for-anticipated-reuse status, and a composting business now operates on roughly 26 acres, employing 20 people as of December 2024.
Community members can review the five-year review report, which is publicly available. For questions about the site, contact the EPA Project Manager or the Remedial Project Manager. For state-related questions, contact the Washington Department of Ecology.
