EPA ID# WA5210890096
EPA Region 10
Skamania County
North Bonneville

3rd Congressional District

Other Names:
Last Update: May, 2010

Hide details for Site DescriptionSite Description

Hamilton Island Landfill was a 240-acre site located in Skamania County in southwestern Washington. This site is owned and managed by the U.S. Army Corps of Engineers (USA/COE). From 1977 to 1982, this unlined landfill was used to dispose of approximately 19 million cubic yards of material excavated during the construction of a powerhouse for the Bonneville dam, which lies one mile upstream, as well as the debris collected during the demolition of a nearby town. Suspected chemical wastes included paints and degreasers. Approximately 900 people obtain their drinking water from wells located within four miles of the site. The Columbia River, a highly productive area for commercial and recreational fisheries, boating, sight-seeing, and wind surfing, is next to the site. The site lies within a Federally-designated National Scenic Area.

Site Responsibility: This site has been addressed through State and Federal actions.

NPL Listing HistoryDates
Proposed Date:07/29/1991
Removed Date:
Withdrawal Date:
Final Date:10/14/1992
Deleted Date:05/25/1995

Hide details for Threats and ContaminantsThreats and Contaminants

Media Affected: Groundwater, Soil & Sludges, Surface Water
Initial sampling indicated that surface and subsurface soil, groundwater, and leachate were contaminated with elevated levels of heavy metals including arsenic and cadmium, and various volatile and semi-volatile organic compounds (VOCs). However, the remedial investigation determined that hazardous substances at Hamilton Island do not pose a risk to human health and the environment.

Hide details for Cleanup ProgressCleanup Progress

Early Actions: The U.S. Army fenced a portion of the site in 1987, restricting public access to the site and preventing direct contact with suspected contamination.

Long-Term Actions: In the Fall of 1993, the U.S. Army began investigations into the nature and extent of site contamination. These investigations detected no hazardous wastes that required a cleanup action. Therefore, in March, 1995, EPA, the Washington Department of Ecology (WDOE), and the U.S. Army determined that no further action would be taken on Hamilton Island.

The site was deleted from the National priorities List (NPL) on May 25, 1995.

The site was reviewed and confirmed Ready for Anticipated Use (RAU) in 2006.

Hide details for Regional ContactsRegional Contacts

E-MAIL ADDRESS:cora.christopher@epa.gov
PHONE NUMBER:206-553-1478
Information pertaining to this site is housed at the following location(s):
North Bonneville City Hall (Selected Documents)
Community Library
North Bonneville, WA

Bonneville Dam Second Powerhouse Visitor Center (Selected Documents)
Skamania County Courthouse
Stevenson, WA

US Army Corps of Engineers, Portland District (Administrative Record)
333 SW 1st Avenue
P.O. Box 2946
Portland, OR 97204