Located in southeastern Washington State, Hanford is a 1,520-square-kilometer (586-square-mile) site created in 1943 as part of the Manhattan Project. The Manhattan Project was America’s effort to develop the atomic bomb before Nazi Germany. The effort at Hanford focused on making plutonium for such bombs.

Operation of the plutonium-producing facilities continued beyond World War II through the Cold War, and a total of nine nuclear reactors were eventually constructed along the Columbia River.

In 1989, production operations stopped and the Site’s mission shifted to cleanup of portions of the site contaminated with hazardous substances, including both radionuclides and chemical waste.

While the operations at Hanford played a role in both World War II and the Cold War, they also created one of the largest and most complex cleanup projects in United States history. Weapons production at Hanford resulted in more than 33 million cubic meters (43 million cubic yards) of radioactive waste and over 100 million cubic meters (over 130 million cubic yards) of contaminated soil and debris. Approximately 1.8 trillion liters (475 billion gallons) of contaminated water was discharged to the soil. Some of the contaminants have made it to groundwater under the site and there are several large contaminant plumes. Over 200 square kilometers (80 square miles) of groundwater is contaminated above groundwater protection standards on the Hanford Site. After more than forty years of plutonium production, activities at the Hanford Site are now based on waste management, environmental restoration, and science and technology.