Superfund Site Profile
The 240-acre Hamilton Island Landfill (USA/COE) site is located in Skamania County, Washington. From 1977 to 1982, site operators used this unlined landfill to dispose of about 19 million cubic yards of material excavated during the construction of a powerhouse for the Bonneville dam; debris collected during the demolition of a nearby town; and chemical waste, paints and degreasers. Initial sampling indicated that site activities contaminated soil, sludge, groundwater and surface water with hazardous chemicals. However, the remedial investigation later determined that hazardous substances at Hamilton Island do not pose a risk to human health and the environment. EPA took the site off the Superfund program’s National Priorities List (NPL) in 1995.