EPA ID# WA2890090077
EPA Region 10
Benton County

4th Congressional District

Other Names: USDOE-Hanford Site-300 Area
Last Update: May, 2010

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The Hanford 300 Area is composed of a 0.52-square mile industrial complex and 1 square mile of surrounding areas used for solid and liquid waste disposal next to the Columbia River about 1 mile north of Richland, Washington. It is one of the three areas at the Hanford Nuclear Reservation on EPA's National Priorities List (NPL); the other two are the 100 and 200 Areas. These areas are part of a Department of Energy (DOE) complex that includes buildings, disposal sites, an environmental research park, and vacant land covering about 586 square miles. Hanford was established in the 1940s to make plutonium for nuclear weapons. The nearby Columbia River provided cooling waters for the reactors producing the nuclear materials.

The DOE fabricated fuel for nuclear reactors in the 300 Area and utilized other 300 Area facilities for research and development purposes. The disposal areas and plumes of contaminated groundwater cover approximately 1.6 square miles. DOE and its predecessor disposed of about 27 million cubic yards of solid and diluted liquid wastes mixed with radioactive and hazardous wastes in ponds, trenches, and landfills in the 300 Area. The areas used for liquid discharges had no outlets; therefore, liquids percolated through the soil into the groundwater and the Columbia River, which is located directly east and downgradient from the 300 Area. The shallow groundwater underlying this portion of Hanford consists of a sand and gravel aquifer which facilitates the movement of contaminants through water. The Columbia River is used for industrial process water, boating, fishing, hunting, and as a supply of drinking water three miles downstream of the 300 Area. The cities of Richland, Pasco, and Kennewick, with a combined population of approximately 150,000 people, maintain water intakes in the Columbia River for the bulk of their municipal supply system, but occasionally mix it with groundwater from municipal wells drilled in the sand and gravel aquifer. Half a million people live within 50 miles of Hanford.

Site Responsibility: This site is being addressed through federal and state actions.

NPL Listing HistoryDates
Proposed Date:06/24/1988
Removed Date:
Withdrawal Date:
Final Date:10/04/1989
Deleted Date:

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Under an Interagency Agreement and Consent Order for cleanup and regulatory compliance at the DOE's waste sites at Hanford, EPA, DOE, and Washington State Department of Ecology jointly developed an action plan that addresses CERCLA and Resource Conservation and Recovery Act (RCRA)-related issues at Hanford. Waste sites and contaminated facilities are being remediated and removed.

As of the end of 2009, 96 waste sites had been remediated. Recently, 180,000 tons of waste was disposed at the Environmental Restoration Disposal Facility in 2008, and 95,380 tons in 2009. From August 25, 2005 to April 19, 2010, 410,780 tons of waste from these waste site remedial actions has been disposed. 144 facilities have been demolished and waste removed for disposal. 111 facilities remain. Most of the building cleanup removal actions have been performed in the past few years. From August 25, 2005 to April 19, 2010, 61,795 tons of waste from these facilities removal actions has been disposed. For both waste site remediation and facility removal actions, the combined waste disposal to the Environmental Restoration Disposal Facility from July 1, 1996 to April 18, 2010 is 1,699,890 tons.

The selected remedy for uranium-contaminated groundwater in the 300 Area is monitored natural attenuation, but this interim remedy is being reevaluated as part of the RI/FS process to support a final ROD for source and groundwater. The RI/FS Work Plan was approved April 8, 2010.

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