NPL Partial Site Deletion Narrative Queen City Farms Maple Valley, Washington On September 30, 2020, the EPA deleted the surface and subsurface soils of the Queen City Farms Superfund site located in Maple Valley, King County, Washington, from the National Priorities List (NPL). The groundwater will remain on the NPL. The 324-acre site is located approximately 2.5 miles northwest of Maple Valley in a rural upland area off Cedar Grove Road SE. The area includes two lakes, one natural and one a remnant of gravel mining, and several large wetland areas. The site is mostly undeveloped and zoned industrial/mining. The southern portion of the site is undergoing reclamation from gravel mining that occurred from the mid-1970s to 1992. The northwestern corner of the site is used by Cedar Grover Composting to produce compost from green waste. The site is bordered by rural residential areas to the east, south and southwest. Cedar Hills Landfill is located north of the site. Local industries disposed of industrial waste liquids in a three-acre area in the northeastern portion of the site from approximately 1955 through the late 1960s. The wastes - including paint and petroleum products, organic solvents and oils - were discharged directly into Ponds 1, 2, and 3. The ponds were reportedly burned to reduce the volume of waste, allowing for the disposal of additional wastes. These ponds were the primary source of soil and groundwater contamination at the site. From 1966 to 1986, 4-Tek Industries (4-Tek) repackaged degreasers and surfactants into smaller containers for resale on two acres in the western portion of the site. Surface water runoff from the chemical storage and mixing areas drained through an 8-inch pipe. Surface soil and shallow groundwater samples from near the sump, contained tetrachloroethylene (PCE) and other volatile organic compounds (VOCs). The site has two operable units (OUs): OU1 addresses the waste disposal area and associated groundwater contamination, OU2 addresses the area near the former 4-Tek sump. Surface and subsurface soils in both OUs are being deleted from the NPL. The EPA sampled water, sludge and sediment from the three waste ponds in 1980 and identified 54 priority pollutants at levels of potential concern. The site was added to the NPL in 1984. The potentially responsible parties (PRPs) at the site are Queen City Farms, Inc. (QCF), the Boeing Company (Boeing), and King County. In 1985, a consent order was signed by the EPA, QCF, and Boeing to drain Ponds 1, 2 and 3 and remove the most heavily contaminated materials. In 1986, QCF signed a consent order with Washington Department of Ecology (Ecology) to implement additional source control measures. Approximately 23,750 tons of oily bottom sludge, 500 to 700 drums and 482,000 gallons of water were removed and transported off-site for disposal. This area, known as the Interim Remedial Measure (IRM) area, was back filled with clean soil and capped. Soil in the 4-Tek sump area was sampled in 1985 and 1987. These samples indicated the presence of several VOCs including PCE, trichloroethylene (TCE), toluene and methylene chloride. In 1990, QCF began a removal action to excavate approximately 170 cubic yards of contaminated soil and 40 cubic yards of concrete for off-site disposal. In 1988, crushed drums, contaminated soils, liquid wastes, and other materials were unearthed by gravel mining activities in an area southwest of IRM. Sampling in the Buried Drum Area (BDA) indicated the presence of pentachlorophenol (PCP), toluene, ethylbenzene, PCE, xylenes and heavy metals. QCF performed a removal action in 1988 in which the exposed drums were removed, drained, and disposed off-site. The contaminated soil was removed, covered with a tarp and temporarily stored. In 1995, 11,000 cubic yards of PCB-contaminated soils and debris were excavated from the BDA. Approximately 2,300 cubic yards of the excavated soil were disposed off-site. In 1996, a barrier system/slurry wall was constructed around the IRM to isolate contaminated soils. The contaminated soil from the BDA and other excavation efforts were placed in a waste cell within the wall. This cell was capped to prevent human contact with hazardous soils. All uncontained soils meet soil cleanup levels. The EPA and the state of Washington, through Ecology, have determined that all appropriate response actions under CERCLA have been completed for the surface and subsurface soils. Therefore, the EPA is deleting the surface and subsurface soil of the Queen City Farms site from the NPL. The groundwater at the site will remain on the NPL. ------- |