Contaminants include hexavalent chromium, strontium-90, uranium, carbon tetrachloride, technetium-99, trichloroethylene, and tritium. Today, the Department of Energy (DOE) and its contractor Central Plateau Cleanup Company (CPCCo) have implemented a comprehensive groundwater treatment strategy across the Hanford Site to prevent contaminants from reaching the Columbia River.

The program features over 2,000 wells, five operational pump-and-treat facilities along the Columbia River, and one at the center of the Site. Collectively, these systems treated over 2.2 billion gallons of groundwater last year and have treated over 23 billion gallons since the beginning of cleanup, removing more than 500 tons of contaminants.