The Dayton Project: How Dayton, Ohio, Made the Atomic Bomb's Polonium

Dayton's secret invention

Dayton, Ohio, is known for cash registers, Cheez-It crackers, pop-top cans and as the Birthplace of Aviation. Less known is the Dayton Project: scientific work across the city in the 1940s that produced the polonium initiators for the Manhattan Project's atomic bombs in World War II.

How it began

The Dayton Project, a branch of the Manhattan Project, began in 1943, when Dr. Charles Allen Thomas, director of Monsanto Chemical Company's Central Research Department, met General Leslie Groves. After several meetings, Monsanto and Thomas were given the job of studying polonium's chemistry and metallurgy for the initiators — in Dayton.

Why polonium

Marie and Pierre Curie discovered polonium in 1898, naming it after Marie's homeland, Poland, and found it far more radioactive than uranium. The isotope polonium-210 suited the initiators: it can be made artificially, gives off plenty of energetic alpha particles, and has other traits that make it workable.

The units

The project began at Monsanto's Central Research Department near downtown Dayton and soon outgrew it, adding units and a warehouse across the city and a suburb:

• Unit I — mostly organizing and recruiting staff.
• Unit II — the Monsanto Rocket Propellant Lab, whose work was unrelated; the project used it for storage.
• Unit III — the Bonebrake Theological Seminary, rented from the Dayton Board of Education, home to all polonium research and development from October 1943 until it too was outgrown.
• Unit IV — the Runnymede Playhouse, the best known. It stood on the Talbott family estate in wealthy Oakwood, a large private recreation hall where the family entertained. Thomas may have known it because in 1926 he married Margaret Stoddard Talbott, one of the family's daughters; the playhouse was built in 1927. The project's Production Group moved in in June 1944, and by June 1945 it was making 35 curies (7 milligrams) of polonium-210 a week and shipping it to Los Alamos.

After the war

Runnymede stayed the production site through the war's end. Postwar demand called for a permanent plant: the project, 43 people in 1943, had 843 by 1948.

• Unit V, Mound Laboratory in Miamisburg, was named for the large cone-shaped earthen mound built nearby by the Adena culture. Building began in 1946; it opened in 1948, and polonium processing began in February 1949. Retired Monsanto/Mound employee Ken Foster recalled escorting one transfer: trays of specimens packed into an AEC car and driven from Oakwood to Miamisburg, in radio contact with Mound's guard station the whole way.
• Unit VI, Scioto Laboratory in Marion, Ohio, was built as Mound's backup, in operation from 1949 through 1954 but kept on cold standby; in 1953 it was judged unneeded and shutdown began.

Mound Laboratory ran from 1948 through 2003, researching, developing and producing for the nation's nuclear weapons, energy and space programs. Its technology lives on: two Mound scientists invented the radioisotope thermoelectric generator (RTG), which powers spacecraft and draws interest from private space companies.

Visit

The Mound Cold War Discovery Center, in one of the old Mound Lab buildings (Building 102) still on the site, preserves and shares Mound's history, the Dayton Project included. The exhibits are free; guided tours and educational programs cost a small fee. Plan a visit.

Sources

Based on "Dayton, OH," by Jaclyn Miller, site manager of the Mound Cold War Discovery Center with Dayton History, Manhattan Project National Historical Park, National Park Service, drawing on histories of Mound Laboratory by Kenneth W. Foster, Floyd R. Hertweck Jr. and H.E. Meyer, Harvey V. Moyer's Polonium (1956) and B. Cameron Reed (2019); published by the National Park Service and in the public domain; rewritten in hubnx's own words. Photographs credited to the Mound Science & Energy Museum Association and the Mound Cold War Discovery Center are not reproduced.