One of the best-kept secrets of World War II was America’s significant effort to build the atomic bomb.
The Corps of Engineers played a key role in both building the bomb, and in keeping the effort necessarily secret.
Shortly after the Pearl Harbor attack the Nation embarked upon building an atomic bomb. On June 17, 1942, President Roosevelt decided to turn over the Manhattan Project to the Army because this large-scale project required a governmental group accustomed to managing large projects, and the project and its large funding needed to be kept secret. Also, the Corps’ construction expertise made it the logical choice to build production facilities.
After the Corps was selected to manage the project, most of the development and assembly work for the bomb took place during the war at the three primary Manhattan Project sites—Oak Ridge, Tenn.; Hanford, Wash.; and Los Alamos, N.M.—though important work took place in many places around the country.
Hanford was selected because Bonneville and Grand Coulee Dams offered substantial hydroelectric power. Also:
o The flat-but-rocky terrain would provide excellent support for the massive plutonium production buildings.
o The expansive and isolated site was far enough inland to meet security requirements.
o Existing transportation facilities could quickly be improved.
o Labor was readily available.
However, Manhattan was the location of key early work, including the organization of the Manhattan Project.
The project office was at 270 Broadway, which was also then the location of the Corps’ North Atlantic Division. There were additional offices in the Woolworth Building at 233 Broadway. A front company established to purchase uranium secretly for the project was also in the Woolworth Building. At these two addresses, employees conducted much of the early research, performed administrative duties, and procured materials for the Manhattan Project.
The first batch of uranium ore purchased by the Corps was actually stored in Manhattan, as well as on Staten Island. The Manhattan District purchased the ore, mined in the Belgian Congo, from the Union Minière Company, which had an office at 25 Broadway in the Cunard Building.
Columbia University, on the northwest end of Manhattan Island, also played a part in the efforts of the Manhattan Project. Scientists in the physics department, before and during the war, conducted experiments that helped unlock the secrets of practical nuclear fission. Even as some of Columbia’s scientists left the university to work on the Manhattan Project, research continued throughout the war.
Though the Manhattan District office in New York remained open until the end of the war, the Manhattan Project headquarters moved to Oak Ridge in August 1943, and Brigadier General Leslie Groves, appointed to command the Manhattan Project in 1942, established his office in Washington, D.C.
The original proposed code name of the Manhattan Project was “Laboratory for the Development of Substitute Materials.” Instead, the Corps established the “Manhattan District” as camouflage, though it was not just a name. Much of the early work leading to the development of the atomic bomb occurred in Manhattan. While the name “Manhattan District” does not evoke the sense of exotic intrigue that an unusual code word or phrase might, it helped to keep secret one of the most important scientific developments of the twentieth century, which was one of the Corps’ greatest accomplishments.