1943-45

The Hanford Site was built in Richland, Washington by the Manhattan Project to produce plutonium. Plutonium is a radioactive element that can be produced by bombarding uranium with neutrons. Until November 1942, the Manhattan Project leaders had assumed that the plutonium operation would be located at the Clinton Engineer Works in Oak Ridge, Tennessee. However, they decided it would be safer to build the operation in a more isolated area where an unforeseen accident wouldn't threaten a city or another Manhattan Project plant. The Manhattan Project chose a 625-square-mile site on the Columbia River in south central Washington. This site offered flat terrain, substantial hydroelectric power, isolation, and existing transportation facilities. Under the War Powers Act, the government offered the residents of Hanford, White Bluffs, Richland, and the surrounding farmland--about 1,500 people--compensation for their land and ordered them to leave.

During the summer of 1943, thousands of workers poured into Hanford, its population growing to 50,000 by the summer of 1944. The first reactor began operation in September 1944. Hanford supplied plutonium for the first atomic device tested near Alamogordo, New Mexico in July 1945 and for the atomic bomb dropped on Nagasaki, Japan in August 1945.