The Hanford Engineer Works (HEW) was a nuclear production complex in Benton County in the US state of Washington, established in early 1943 as part of the Manhattan Project during World War II. Plutonium manufactured at the HEW was used in the atomic bomb detonated in the Trinity test on 16 July 1945, and the Fat Man bomb used in the bombing of Nagasaki on 9 August 1945. DuPont was the prime contractor for its design, construction and operation. The land acquisition was one of the largest in US history. The construction workforce reached a peak of nearly 45,000 in June 1944. B Reactor, the world's first full-scale plutonium production nuclear reactor, went critical in September 1944, followed by D and F Reactors in December 1944 and February 1945, respectively. The HEW suffered an outage on 10 March 1945 due to a Japanese balloon bomb. The total cost of the HEW up to December 1946 was more than $348 million (equivalent to $4.1 billion in 2023). (Full article...)