Book Review: Polonium in the Playhouse, The Manhattan Project’s Secret Chemistry Work in Dayton, Ohio by Linda C. Thomas

Even after more than 70 years, details of some important aspects of the Manhattan Project remain only partially known to scholars of the Project, let alone the public at large. Linda Thomas’s Polonium in the Playhouse fills a gap in Manhattan history with a very readable, fast-paced, well-illustrated, and carefully documented treatment of a highly-secret Project facility operated by the Monsanto Chemical Company in an upscale residential neighborhood of Dayton, Ohio. This facility was devoted to extracting and purifying polonium, a key ingredient in the neutron-emitting “initiators” used in the Trinity, Hiroshima, and Nagasaki atomic bombs. Details of the Dayton project were not declassified until 1983, and some aspects of the associated chemical research still remain under wraps. As the Dayton work was not mentioned in Henry Smyth’s 1945 Atomic Energy for Military Purposes public report on the bomb project, it has been largely overlooked by Manhattan scholars. (Disclosure: This reviewer served as a reviewer for some of the chapters of this book while it was in preparation.)

In effect, this volume is two books in one: A history of the Dayton project, and a biography of the author’s grandfather, Charles Allen Thomas, a Monsanto executive who was appointed to coordinate all Manhattan Project chemistry research. With access to family papers complemented with interviews and documents accessed through numerous Freedom of Information Act requests, the author is uniquely positioned to relate this story. The Manhattan Project was immensely complex, but Thomas does an excellent job of describing its scientific and organizational background and the work of its major facilities and laboratories in just enough detail to set the stage for how the Dayton project fit into to the overall picture.

Design of the bomb initiators is still one of the most closely-classified elements of the Manhattan Project. These devices, each about the size of a golf ball, were designed to create a brief torrent of neutrons to initiate the nuclear chain reaction by what are known as “alpha-n” reactions, wherein alpha-particles emitted by a naturally-radioactive material strike a light-element material, resulting in the emission of neutrons. Polonium (Po) is ideal as the alpha-emitter because of its short (138-day) half-life; a mere 0.24 milligrams of Po emits as many alpha particles per second as a full gram of radium (which defines 1 Curie). More recently, polonium was the poison involved in the infamous murder of former KGB agent Alexander Litvinenko in 2006. Manhattan Project initiators were of the so-called “Po-Be” type, which meant that they contained polonium as the alpha-emitter and beryllium as the light element. The two elements were contained within the initiator but were initially separated; when the initiator was crushed by the assembling bomb core they mixed, producing the initiating neutrons. Because of the short half-life of Po, these initiators had limited half-lives, and so it was necessary to establish a dependable supply chain of this otherwise rare element. Only two methods of sourcing Po are available: By extracting it from waste lead-dioxide ores from uranium and radium-mining operations, or by breeding it synthetically via neutron bombardment of bismuth within a reactor. In the latter case, nuclei of Bi-209, by capturing neutrons, become nuclei of Bi-210, which transmute to Po-210 via beta-decay with a half-life of about 5 days. The cross-section for this process is small, however, so it is necessary to irradiate hundreds of pounds of bismuth to produce Curie-level amounts of Po. Manhattan Project initiators each used about 50 Curies of Po, equivalent to about 10 milligrams. The task of the Dayton project was to research and develop the chemical processes necessary to realize both methods, using polonium-bearing ores from Canadian mines and slugs of bismuth irradiated in the Oak Ridge and Hanford reactors.

The central figure of the story, George Allen Thomas, was born near Lexington, Kentucky, in 1900. His interest in chemistry was apparent at a young age, and after skipping two years in high school he enrolled in Transylvania University, graduating in 1920. He then went on to graduate school at MIT, from which he graduated with an MS in 1924. Through a classmate who was a member of the DuPont family, Thomas landed a job at the Ethyl Corporation (a subsidiary of General Motors) in Dayton, where he researched motor fuels. Popular, extroverted, and a natural leader, he began to move easily in upper-crust Dayton social circles, and in 1926 married into the very wealthy Talbott family, whose patriarch, Harold Talbott, was a part owner of GM. At about this time, GM decided to move Ethyl operations to Detroit; not wishing to move, Thomas and a co-worker, Carroll Hochwalt, decided to start their own chemical consulting business, Thomas & Hochwalt Laboratories. Their first major product was a revolutionary new fire extinguisher; during Prohibition they devised a method to analyze the safety of bootleg liquor and also developed a means of artificially ageing raw liquor in anticipation of Repeal.

As Thomas and Hochwalt were building their business, Thomas’s mother-in-law, Katherine Talbott, built a recreation center for social and sporting events dubbed “Runnymede Playhouse” on the grounds of the family estate. The glass-roofed structure, built at a cost of $100,000, was at the time the largest free-standing private hall in the country, boasting a stage, dressing rooms, tennis and squash courts, a greenhouse, and a swimming pool; the main dining area could accommodate 1200 bridge players at once. Runnymede would play a crucial role in the Dayton project.

Thomas & Hochwalt thrived; by 1935 it was the largest independent consulting laboratory in the country, and the next year they were bought out by Monsanto, which made the facility the nucleus of the company’s Central Research Division with Thomas as Director. When the National Defense Research Committee and later the Office of Scientific Research and Development were formed under Vannevar Bush and James Conant, Monsanto received numerous contracts for liquid fuels and synthetic rubber work. Thomas became well-connected to those agencies; at the time of the Japanese attack at Pearl Harbor he was deputy chief of the NDRC’s explosives division.

When the Los Alamos Laboratory was established in the spring of 1943, it became clear that the Manhattan Project’s need for chemical and metallurgical research, which was spread among sites at Los Alamos, Berkeley, and the University of Chicago, was going to be much greater than initially appreciated, and required a experienced science administrator. General Groves offered Thomas a position as an associate Director of Los Alamos; he declined the offer, but did agree to coordinate Project chemistry while remaining in Dayton. Over the next two years travel to Project sites would keep him away from home for two weeks of every month.

In May 1943, Monsanto was awarded a contract to produce polonium, and Thomas set up operations in Dayton. This work was regarded as so sensitive that materials could not be ordered through normal Manhattan Engineer District procurement channels; rather, they were sourced through existing Monsanto contracts. From an original estimate of requiring only 12 chemists, the Dayton project grew to a staff of 200 spread among four buildings by the end of the war. Many of these people were be involved in developing new radiation-counting instruments and in staffing an extensive health physics program. One of the health physics staff members, George Koval, would later be revealed as a Soviet agent.

Chemists will enjoy Thomas’s descriptions of the processes involved in extracting minute amounts of polonium from ores and bismuth slugs. The scale of the ore work and the need to handle 110-pound bismuth slugs demanded an expansion of laboratory space, and the Army Corps of Engineers seized Mrs. Talbott’s Playhouse (she had died in 1935) and entered into a lease with the family to renovate the structure and use it as a production facility. The cover story for neighbors was that it was a laboratory for producing training films for the Army Signal Corps.

The ore-extraction process was inefficient and was eventually dropped in favor of the bismuth process exclusively, although it did contribute about 40 Curies of Po extracted from 37 tons of ore, enough for about one initiator. Fifty tons of bismuth would be processed; by June, 1945, Dayton was sending 35 Curies of Po per week to Los Alamos, delivered by couriers driving trucks over a 53-hour route which deliberately circumvented cities. Thomas witnessed the Trinity test; his letter to his mother describing that event is worth the cost of this book alone.

After the war, Thomas served on numerous corporate, academic, and government committees and boards, including the one that drafted the 1946 Acheson-Lilienthal report, although he later became skeptical of efforts by intellectuals to influence political events. He became President of Monsanto in 1951, and remained at the company until his retirement in 1970. He passed away in 1982, having never spoken to his family of his connection to the Manhattan Project. The cost of the Dayton project ran to about $3.9 million, a fraction of a percent of the Project’s overall cost of about $2 billion, but without it there would have been no functioning bombs.

As the need for polonium production grew during the Cold War, the Dayton Project outgrew its facilities, and the Atomic Energy Commission established the Mound Laboratory, a purpose-built facility about 10 miles southwest of Dayton, to take on the work. Mound began processing operations in February, 1949; work there also included preparing radioisotopes to power satellites. The Mound Laboratory was decommissioned in 1993. Operations at the Playhouse continued until late 1948; early the next year, the Playhouse, which had become contaminated, was dismantled and the site remediated and returned to the family. The book includes a number of photos of the Playhouse as it was being cleaned up and dismantled.

Appendices to this book include a brief primer on the science underlying the bombs, a log of travels by Dayton personnel among Project sites, and brief biographies of several members of the Dayton staff, a valuable contribution as these names would probably otherwise be lost to history. Books on the Manhattan Project can be notorious for reiterating technical or historical errors, but only one such glitch caught my eye, a statement on page 99 that neutrons are emitted directly by polonium.

Polonium in the Playhouse brings to light a little-known aspect of the Manhattan Project, the work of Charles Allen Thomas, and the underappreciated role of chemistry in the Project. This book should be in the collection of any serious student of the Project.

Cameron Reed is the Charles A. Dana Professor of Physics at Alma College. He served as the editor of the American Physical Society’s “Physics & Society” newsletter from 2009-2013, and is currently Secretary-Treasurer of the APS’s Forum on the History of Physics. His interests lie in the physics and history of nuclear weapons; his text “The History and Science of the Manhattan Project” was published by Springer in late 2013.

The articles in this issue represent the views of their authors and are not necessarily those of the Forum or APS.