Groves takes over the Manhattan Project

War chronologies record under 4 September 1942 that the Manhattan Engineering District was formally created on that day and that work on the atomic bomb and the production of nuclear fuel began in earnest. That account needs correcting. The district was called the Manhattan Engineer District (MED), and it was created by the Chief of the Army Corps of Engineers, Major General Eugene Reybold, by an order of 13 August 1942 (formally 16 August, according to some sources). At the beginning of September no decision was taken that could be regarded as a founding act. The real turning point came two weeks later: on 17 September 1942 the direction of the entire programme was entrusted to Colonel Leslie Groves, and within the following week Groves removed the obstacles that had been holding the work back since June. The chronologies thus capture the meaning of September 1942 well – it was then that the American atomic programme moved into full-scale effort – though not its date.

A slow start

From Einstein’s letter of August 1939 onwards, American research on uranium was carried out by civilian scientists, from 1941 under the aegis of Vannevar Bush’s Office of Scientific Research and Development (OSRD). In June 1942 President Franklin Delano Roosevelt agreed that the Army should take over the construction of the plants, and on 18 June Colonel James C. Marshall was ordered to organise the military side of the programme. Marshall, a conscientious engineer from the Syracuse district, set up an office at 270 Broadway in New York, from which the district took its name, “Manhattan”. His deputy was Lieutenant Colonel Kenneth Nichols.

In the summer of 1942, however, things moved slowly. Marshall held off buying land for the plants in the valley of the Clinch River in eastern Tennessee because he was waiting for the results of reactor experiments. For the project he obtained only an AA-3 supply priority – the same as an ordinary explosives factory – which, in a war economy where hundreds of orders competed for steel, copper and machinery, meant months of delay. Nor had it been settled where uranium was to come from in the quantities required. Bush, whom Roosevelt had told to hurry because the Americans feared the Germans would build the bomb first, complained in August to senior War Department officials about the lack of decisiveness. He proposed placing the whole effort under the supervision of a policy committee and putting a high-ranking officer at the head of the programme, preferably the chief of staff of the Services of Supply, Major General Wilhelm Styer.

Groves is chosen

Styer and his superior, the head of the Services of Supply, General Brehon Somervell, chose someone else, however: Colonel Leslie Richard Groves, the 46-year-old deputy chief of Army construction. Groves had built camps for hundreds of thousands of draftees in 1940–1941 and had overseen the construction of the Pentagon, the world’s largest office building, under way since August 1941 for the War Department. He had a reputation as an exceptionally efficient man, tough and ruthless towards subordinates and contractors.

On 17 September 1942 Somervell stopped Groves in the corridor outside the room in which the colonel had been giving evidence to a congressional committee and told him that the Secretary of War had chosen him for a very important assignment, and that the President had approved the choice. According to Groves’s memoirs, Somervell added: “If you do the job right, it will win the war.” Groves had been hoping for an overseas posting and made no secret of his disappointment. He already knew about the atomic programme through his post – his department approved the Manhattan District’s construction budgets – and he reportedly replied only: “Oh, that thing.”

It was agreed that Groves would be promoted to brigadier general, since the rank of general was meant to give him authority over the scientists, and that he would not formally take command until his promotion. He reported directly to Somervell rather than to the Chief of Engineers, and Colonel Marshall, who remained head of the district, was from then on answerable to him. On 17 September itself Groves went to see Bush, who knew nothing of the change. The meeting went badly: Groves would not reveal details, and Bush, taken aback by his brusqueness, wrote afterwards that he doubted whether the new chief had enough tact for the role. He soon came round to Groves’s effectiveness, however.

The first week

Groves acted at once. On 18 September he sent Nichols to the New York office of Edgar Sengier, the Belgian director of the Union Minière du Haut-Katanga company, which mined uranium ore at Shinkolobwe in the Belgian Congo. Sengier, warned earlier by British scientists that uranium might be of military importance, had in the autumn of 1940 secretly shipped some thousand tons of high-grade ore to New York and stored it in sacks in a warehouse on Staten Island. According to Nichols’s account, Sengier greeted him with the words: “You can have the ore right now. It is in New York, a thousand tons of it. I was waiting for your visit.” Within a few hours they agreed the purchase of the entire stock, about 1,200 tons of ore containing up to 65 per cent uranium oxide – incomparably richer than Canadian or American ore – together with the ore still stockpiled in the Congo. The Staten Island ore became the main raw material for the first plants of the Manhattan Project.

On 19 September Groves signed the decision to acquire the site in Tennessee identified back in the summer by Marshall and the engineers of the firm Stone & Webster: tens of thousands of acres of hills and valleys along the Clinch, near Knoxville, where the government power stations of the Tennessee Valley Authority could supply enormous amounts of electricity. That same day he went to the chairman of the War Production Board, Donald Nelson, and demanded the authority to grant the programme the highest, emergency AAA priority. Nelson refused at first, but gave way when Groves threatened to go directly to the President. Groves dictated a ready-made letter, and Nelson signed it.

On 23 September Groves was promoted to brigadier general and formally took charge of the programme. The same day the Army Chief of Staff, General George Marshall, Bush, James Bryant Conant, Somervell, Styer and Groves met in the office of the Secretary of War, Henry Stimson. They set up the Military Policy Committee, subordinate to the Top Policy Group created in 1941: its members were Bush (with Conant as his alternate), Styer and Rear Admiral William Purnell of the Navy, while Groves attended its meetings and carried out its decisions. Bush and Conant were henceforth to advise, but the Army was to be in charge. Groves left the meeting before it ended, explaining that he had a train to catch to Tennessee, and the next day he and Marshall inspected the site on the Clinch.

On 29 September the Under Secretary of War, Robert P. Patterson, approved the compulsory acquisition of some 56,000 acres (23,000 hectares) in Anderson and Roane counties. The decision affected around a thousand farming families, some of whom were given just two weeks to leave farms their families had worked for generations. The site was first named the Kingston Demolition Range, and from 1943 the Clinton Engineer Works. On it grew up the secret town of Oak Ridge.

Full effort

Within a week of his appointment Groves had secured for the programme its raw material, a site for its plants and priority for its supplies – the three things his predecessor had been waiting for since June. From then on the programme ceased to be a collection of university laboratories with a construction office attached and became an industrial undertaking run by the Army. Groves set up his headquarters in Washington, in the War Department building on Virginia Avenue, worked six days a week and spent Sundays touring the construction sites. He imposed strict secrecy and the principle of compartmentalisation: every worker was to know only the part of the task he was carrying out. The scientists, used to a free exchange of ideas, were irritated by this rule, and it brought some of them, such as Leó Szilárd, into sharp conflict with the general.

It was not yet known which method of obtaining fissile material would succeed, so Groves and the committee decided to pursue several routes at once and to start building huge plants straight away, before the laboratory experiments had been completed. It was a gamble measured in hundreds of millions of dollars, but it alone offered a chance of having the bomb during this war. In October 1942 Groves met the physicist Robert Oppenheimer and, against the views of many scientists and of counter-intelligence, decided to entrust him with the direction of the weapons design laboratory. In November the two of them chose the Los Alamos mesa in New Mexico as its site. Groves gave the production of plutonium to the chemical company DuPont. On 2 December 1942 in Chicago Enrico Fermi’s team started up the first nuclear reactor, Chicago Pile-1, confirming that a controlled chain reaction was possible.

Place in the war

It was September 1942, rather than the formal creation of the district in August, that marked the moment when the American atomic weapon turned from a hypothesis into a construction programme. In the years that followed, uranium enrichment plants rose at Oak Ridge, reactors at Hanford on the Columbia River in Washington State, and the laboratory at Los Alamos. At its peak the project employed more than a hundred thousand people, and it cost about 2 billion dollars. The British, who in 1941 had been ahead of the Americans, were cut off from the results for many months by Groves’s restrictive policy; only the Quebec Agreement of August 1943 brought the two programmes together. Despite the secrecy, Soviet intelligence recruited informants within the project, among them Klaus Fuchs.

Germany, whose feared bomb had driven the whole effort, practically abandoned it in 1942, and the scientists of the Uranverein did not build even a working reactor by the end of the war. On 16 July 1945 the first nuclear explosion was set off in the New Mexico desert, and on 6 and 9 August 1945 American bombers dropped bombs on Hiroshima and Nagasaki. For the course of the war and for the world that followed it, the decision of 17 September 1942 proved, in the view of many historians of the programme, to be one of the most important personnel decisions of the entire war.