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Chapter 4: General Groves Takes Command

As the son of an Army chaplain, Leslie R. Groves spent many of his boyhood years on different military posts in the western United States. During these formative years, young Groves often listened to the old Indian fighters who frequented the posts recount many a stirring tale of how the West was won. Their tales fired the boy’s imagination, yet he lamented that those days were past and that there were no more frontiers left for him to conquer. He could not know, of course, that the opportunity to realize his youthful dreams to lead in the exploration and conquest of a new frontier – his to be a scientific and technical one whose developments would have a decisive impact on the future and fate of all mankind – would come as the result of the administrative reorganization of the American atomic energy program in the summer and fall of 1942 and his selection as a 46-year-old career Army officer to be officer in charge of the project.1

Reorganization and the Selection of Groves

On 17 June 1942, President Roosevelt had approved the proposals, made by Vannevar Bush and James B. Conant to the Top Policy Group, that the Army assume overall direction of the atomic program and that the Joint Committee on New Weapons and Equipment (JNW) establish a special subcommittee to consider the military application of atomic energy. Bush, however, who served as JNW chairman, did not see any need for immediate appointment of the subcommittee and thus waited until 10 September to propose to Secretary of War Stimson that a small group of officers be assigned the task of considering possible strategic and tactical uses of atomic energy. When Stimson informed Army Chief of Staff General George C. Marshall of Bush’s request, the general indicated that he felt it was premature and expressed grave concern about the increasing problem of security as more and more people became aware of the existence of the atomic energy program. Despite Marshall’s reservations, it soon became evident that a special committee was needed not only to consider the ultimate uses of atomic energy but also to determine general policies and supervise the growing project. The sequence of events in September 1942 that led to formation

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of a policymaking committee and to strengthening the military leadership of the project seems to have been about as follows.2

Early that month – almost certainly before learning the results of the Bohemian Grove meeting and possibly even before Bush made his recommendations to Stimson – General Styer discussed the status of the atomic energy program with his commander, Lt. Gen. Brehon B. Somervell, Services of Supply (SOS) commanding general, and then with General Marshall. In outlining developments in the program, he emphasized that the Army’s responsibilities were now becoming increasingly large. Then on the sixteenth, or possibly a day or so earlier, Bush, Styer, and Somervell met to discuss the top-level organization of the atomic project. Under Secretary of War Robert P. Patterson also may have been present, or perhaps Somervell saw him separately. At any rate, two decisions were reached: A policy committee would be formed to oversee the program, and an Army officer would be chosen to carry out the policies established by this committee.

Anxious to counteract General Somervell’s tendency to favor giving the Army dominant control of the project, thus relegating the scientists to a lesser role, Bush proposed that the committee should be organized first. Styer and Somervell, however, wanted to choose an officer immediately. The obvious choice was Styer himself, but the job was a full-time one and Somervell was unwilling to lose his chief of staff. Styer then, without hesitation, proposed Colonel Groves, a recommendation readily approved by Generals Somervell and Marshall.

In addition to his impressive general qualifications,3 another factor made

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Groves the logical choice to head the atomic project: As deputy chief of the Engineers’ Construction Division, he had spent considerable time advising District Engineer Marshall in his quest for power resources and in his selection of sites for the Manhattan District facilities. Furthermore, with military construction in the United States past its wartime peak, Groves was seriously considering taking another assignment, probably overseas.

On the morning of 17 September, Groves had to testify on a military housing bill before the House Military Affairs Committee. When he left the hearing room, he encountered General Somervell and learned of his new assignment. Groves later recalled that his first reaction was one of great disappointment at the prospect of missing overseas duty. Somervell, undoubtedly sensing Groves’ lack of enthusiasm for his new job, expressed the opinion that a successful conclusion to the atomic energy program could well have a decisive impact on winning the war.4

Shortly after leaving Capitol Hill, Groves, accompanied by Colonel Nichols (Colonel Marshall was on the West Coast), reported to General Styer for orders. Styer explained the new high-level organization of the project and Groves’ role in it. Groves was to be relieved of his position in the Construction Division. He was, however, to continue to exercise control over construction of the nearly completed Pentagon. In this way he would avoid arousing public curiosity at his sudden absence from this project, which was viewed with great interest by Congress. After the Pentagon job was finished in a few months, Groves was to devote himself entirely to the atomic energy program.

The directive for Groves’ new assignment – Styer had consulted with him on its wording – ordered the Engineers chief, General Reybold, to relieve him “for special duty in connection with the DSM project.”5 The directive emphasized, however, that Groves was to operate closely with the Construction Division and other elements of the Corps of Engineers. He was to have full responsibility for administering the entire project and to make immediate arrangements for priorities, for formation of a committee to formulate military policy governing use of the project’s product output, and for procurement of the Tennessee site as the location for its major activities. He was also instructed to make plans for the organization, construction, operation, and security of the project and, after they had been approved, to undertake the measures necessary to carry them out.

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Styer also informed Groves that General Marshall had directed that he be promoted to the grade of brigadier general. As the list of new promotions would be out in a few days, Groves suggested (and Styer agreed) that he should not take over the project officially until he had received his star. “I thought that there might be some problems in dealing with the many academic scientists involved in the project,” he wrote later, “and I felt that my position would be stronger if they thought of me as a general instead of a promoted colonel.” The new military chief of the atomic project, however, seems not to have considered that for several months Colonel Marshall and other officers had been dealing successfully with project scientists in spite of their relatively low military rank.6

Following the conference with Styer, Groves delivered the directive covering his new assignment to General Reybold and also stopped in the office of his erstwhile chief, General Robins, to brief him on its contents. He then sat down with Colonel Nichols to learn from the deputy district engineer more about the actual status of the project. He was not very pleased with what he learned. “In fact,” he recalled subsequently, “I was horrified. It seemed as if the whole endeavor was founded on possibilities rather than probabilities.”7

On the afternoon of the same day (17 September), Groves and Nichols called on Bush. Unfortunately, no one had yet officially informed the OSRD director of Groves’ assignment to the project. Furthermore, Bush was disturbed that this action was additional evidence that Somervell was intent on having the Army take over control of the atomic energy program to the complete exclusion of the scientists. Consequently, he was most reluctant to answer Groves’ questions and the whole conversation was somewhat one-sided, relatively brief, and, in Groves’ words, “far from satisfactory for both of us.”8

As soon as Groves departed, Bush hurried over to see Styer. He repeated his views that the proposed policy committee should choose its own agent; he “doubted whether he [Groves] had sufficient tact for such a job.” Bush recollected later that Styer disagreed with him on the first point and, while acknowledging that Groves was “blunt etc., ... [he] thought his other qualities would overbalance.” Styer went on to explain that Groves’ assignment already had been approved by General Marshall. Returning to his office, Bush wrote to Harvey Bundy, Stimson’s assistant for scientific matters: “I fear we are in the soup.”9

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For the next few days, Groves was busy preparing for his new assignment, including conferences with Colonel Marshall and Generals Styer and Robins. Robins made a point that the Engineer Department of the Corps of Engineers would have no further responsibility for the program and that the Manhattan District would henceforth report to Groves rather than to the Engineers chief.

On 21 September, Colonels Groves and Marshall called on Bush. This time the OSRD director was cordial and open. He explained his earlier reluctance to talk freely, then briefed Groves thoroughly on the scientific and historical background of the project and cautioned him on the need for tightening security measures. Thus, from what Groves himself later termed an “inauspicious beginning,” relations between the two leaders of the atomic project soon grew into a firm and fruitful friendship, with each expressing the greatest respect for the other’s capabilities.10

On the afternoon of 23 September, a few hours after Groves had been sworn in as a brigadier general and had taken official charge of the atomic project, he went to a meeting convened by Secretary Stimson at the War Department. Present also were Bush, Conant, Bundy and Generals Marshall, Somervell, and Styer. The group agreed to establish a small Military Policy Committee, responsible to the Top Policy Group, to formulate project policies on research and development, construction and production, and strategic and tactical matters. Bush was chosen chairman, with Conant as his alternate; the other members were General Styer and Rear Adm. William R. Purnell, who had replaced Rear Adm. Willis A. Lee, Jr., on the JNW Committee. General Groves was to sit with the committee and to act as its executive officer in carrying out its policies. The new committee was directed to report periodically to the Top Policy Group. The OSRD S-1 Executive Committee was to continue to advise on scientific aspects of the program, with most of the research activities under OSRD direction.11

As soon as the Military Policy Committee had received written approval from the Top Policy Group and the JNW Committee, it assumed virtually complete control of all aspects of the atomic energy program, acting through General Groves as, to use Stimson’s phrase, “the executive head of the development of the enterprise.”12

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First Measures

Acquiring the Tennessee Site

Making a hurried departure from the 23 September meeting at the War Department, Groves went directly to Union Station and caught an overnight train for Knoxville, Tennessee.13 (See Map 1.) The next morning he met Colonel Marshall, who had been rechecking the proposed site for the project. Groves and Marshall spent the day going over the site as carefully and thoroughly as was practicable on existing roads. “It was evident that it was an even better choice than ... [he] had anticipated.”14 Well satisfied that the site would meet all requirements, and knowing that preliminary steps for acquisition were under way, Groves telephoned Col. John J. O’Brien of the Engineers’ Real Estate Branch to proceed at once with formal acquisition.

The roughly rectangular site, about 16 miles long and 7 miles wide, covered substantial portions of both Roane and Anderson Counties. It was located approximately midway between the two county seats, Kingston and Clinton, and about 12 miles west of Knoxville, the nearest city. Bounded on three sides by the meandering Clinch River and on the northwest by Black Oak Ridge, the terrain of the site was typical of the region. Wooded ridges, running more or less parallel to its long axis, rose generally about 200 feet above narrow valleys. Of the approximately one thousand families, most resided on farms or in one of several small hamlets.

On 29 September, Under Secretary of War Patterson authorized the Engineers to acquire the some 56,000 acres at an estimated cost of $3.5 million. Subsequent additions brought the total to about 59,000 acres. On 7 October, a court-approved condemnation for the whole area went into effect, and within a month the first residents began to leave. Construction began almost immediately. Ultimate acquisition of the entire site would not be completed without many problems, but now, at least, the first essential step toward building the great plants for producing fissionable materials had been taken.15

For security reasons earliest public references to the site indicated it was an artillery and bombing practice area, and for several weeks it was known as the Kingston Demolition Range. The official designation, however, and the name that was released to the public in late January 1943, was the Clinton Engineer Works. Project leaders chose the name of the town located a few miles northeast of the site as being least likely to draw attention to the atomic energy activities at the site. The Clinton Engineer Works continued to be the Tennessee

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area’s official designation as long as it remained under Army control. In mid-1943, when permanent housing for the site’s growing population was erected along Black Oak Ridge, the town site became known as Oak Ridge, and this name was used as the post office address.16

Procuring Uranium

Whether the Manhattan Project had sufficient uranium ore to fulfill its mission, Groves felt, was of paramount importance.17 Immediately after his 17 September departure from the Corps and before he officially assumed his new position as Manhattan commander, he took steps to ascertain the availability of uranium to the project. Informed by Colonel Nichols of the contracts already made with Edgar Sengier of Union Miniere and of the Bohemian Grove decision to acquire the company’s reserve of ore on Staten Island, Groves directed Nichols to press the negotiations with the mining executive.

During the previous week Colonel Nichols, Capt. John R. Ruhoff, assistant chief of the District’s Materials Section, and officials of the Standard Oil Development Company and the Stone and Webster Engineering Corporation had agreed that Ruhoff should arrange for a test of the Staten Island ore to determine the percentage of recoverable U308 (uranium oxide) and, on the fifteenth, Ruhoff had secured Sengier’s release of 100 tons for shipment to Eldorado Gold Mines’ Port Hope refinery. In the meantime, Nichols had obtained the necessary export licenses through the State Department.

In follow-up negotiations with Sengier on 18, 23 and 25 September, Nichols arranged for procurement of the Staten Island ore. The time required to work out the necessary arrangements with both Eldorado Gold Mines and its marketing agent, the Canadian Radium and Uranium Corporation, delayed signing of the contract until 19 October. It called for purchase by the United States of the uranium content of 100 tons of ore, with Union Miniere’s African Metals retaining ownership of the radium in the ore. Also, the United States was to have an option to purchase the remaining 1,100 tons of uranium ore on Staten Island, assayed at 65 percent uranium oxide, as well as about twice that amount of approximately 20 percent ore in storage in the Belgian Congo. Except for that

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ore shipped immediately to Port Hope for processing (the first 100 tons reached there in November), all Staten Island ore was to be transferred to Seneca Ordnance Depot at Romulus, New York, for safekeeping. Subsequent contracts covered purchase of additional Congo uranium on terms similar to those set forth in the 19 October agreement.

Working in close consultation with Maj. Gen. Charles P. Gross, the Army’s Transportation chief, Manhattan officials arranged for shipping the ore from Africa by the safest and swiftest means available. Based upon Sengier’s recommendations, fast motor ships traveling out of convoy were employed to traverse the submarine- infested South Atlantic. Because the ore arrived at the port of New York considerably faster than it could be refined, it was assayed and stored in a warehouse at Middlesex, New Jersey, especially leased by the Army for that purpose.18

In a move to further expedite the uranium program and, at the same time, to relieve overburdened Stone and Webster of part of its extensive assignment, the Manhattan District assumed responsibility for procurement and preliminary refining of the ore. Capt. Phillip L. Merritt, a trained geologist who was already on the staff, was assigned to monitor these activities. Working under the general guidance of Colonel Nichols, Merritt gave special attention to the project’s worldwide search for possible additional sources of uranium.

Toward the end of 1942, the Eldorado mine in Canada resumed operations. Meanwhile, the District made arrangements for uranium extraction from tailings of Colorado Plateau carnotite ores mined originally for their radium and vanadium content. In January 1943, the War Production Board (WBP) issued orders (subsequently amended in August) that future sale or purchase of uranium compounds was limited to the atomic program, except for essential military and industrial applications. Even before the board acted, Manhattan’s Military Policy Committee had reported optimistically to the President that the project had “either in hand or on the way, sufficient uranium for the entire program up to and including military use.”19

Obtaining Priority Ratings

In June 1942, President Roosevelt had endorsed a recommendation by the Top Policy Group that the atomic energy program should be assigned the highest priorities to facilitate procurement of the tools and materials required to produce an atomic bomb.20 Yet, by September, as

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Groves assumed overall administrative leadership of the project, it was evident that the AA-3 base rating Colonel Marshall had secured in July was not going to be adequate to ensure the uninterrupted development of the atomic program. Consequently, following consultation with General Styer, Groves moved immediately to obtain for the project the priority rating he believed was essential for its successful continuation.

Both generals had decided to seek broad authority for the District to issue an AAA priority whenever there was a need to break a bottleneck. When Groves called on WPB Chairman Donald Nelson on 19 September, he had with him the draft of a brief letter – addressed to himself and to be signed by Nelson – in which he had incorporated the idea of assigning the desired AAA authority to the project. As Groves later recalled, Nelson’s first reaction was negative; however, when the general threatened to take the matter to the President, the chairman changed his mind. Whether or not other pressure already had been brought to bear on Nelson is not known, but he did agree to sign the letter as Groves had written it.

I am in full accord it read] with the prompt delegation of power by the Army and Navy Munitions Board [ANMB] through you to the District Engineer, Manhattan District, to assign an AAA rating, or whatever lesser rating will be sufficient, to those items the delivery of which, in his opinion, cannot otherwise be secured in time for the successful prosecution of the work under his charge.21

On 26 September, the ANMB issued the District a blank check to assign the AAA priority. But General Weaver, senior Army representative on the ANMB, warned Groves that use of this AAA authority must not interfere unnecessarily with other high-priority programs and that, with each use of the rating, a written report must be submitted within a 24-hour period. That same day, at his first meeting with the S-1 Executive Committee, Groves explained to the group that the AAA priority would not be used for the entire project, but only when progress would be unduly delayed by employment of any lower rating. And to ensure retention of AAA authority, an AA-3 or lesser priority would be utilized whenever possible. Before adjourning, the conferees agreed that the OSRD would continue to deal with its own priority problems as far as possible, with the Army lending assistance when necessary, and that the Washington Liaison Office of the Manhattan District would handle the general administration and coordination of priorities for all future procurement for the atomic project.

Now that the District had AAA authority as a backup to overcome procurement obstacles, both Groves and

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Styer believed that development of the atomic program could continue with the AA-3 base rating. By 1943, however, the project’s unfolding requirements revealed that for even routine procurement the AA-3 rating was inadequate and the AAA rating unnecessarily high. To remedy this situation, Groves wrote to General Weaver in early February and requested that the District’s priority “authority given in [the] letter of September 26, 1942 be amplified to include use of AA-1 and AA-2 ratings.”22 Although the Nelson letter had referred to the use of lesser ratings than AAA whenever these would suffice, the fact that the Joint Chiefs of Staff had forbidden use of AA-1 or AA-2 for construction projects had ruled out their earlier use by the District. Weaver officially responded on 22 March, upgrading the rating of AA-3 to AA-2X – a new priority created to provide supplies and services for urgent foreign and domestic industrial programs.

Groves, however, still was not satisfied and, in the months that followed, continued to press ANMB officials to assign the maximum AA-1 base rating. Time passed, but the general persisted in order to achieve his objective. Finally, on 1 July 1944, the District received AA-1 authority.

Following District policy, the Washington Liaison Office was to use the lowest rating that would bring about the required delivery of materials. But to counter the threat from other urgent wartime programs during the District’s massive procurement and construction phase between 1943 and early 1945, the officer assigned emergency priorities at the AAA level for more than $77 million worth of orders. At times, the Manhattan Project was using more AAA ratings than the combined total for all other Army and non-Army programs. Yet, through the exercise of discretion, Groves and his staff were able to avoid not only strong criticism of their actions but also attempts to revoke the District’s AAA authority. Groves’ success in obtaining the successive advances in the priority status of the Manhattan Project ensured that, despite occasional problems and annoyances, procurement needs for the atomic program were met.

Establishment of Los Alamos

In the late summer of 1942, J. Robert Oppenheimer, the University of California physicist who was directing the theoretical aspects of designing and building an atomic bomb, became convinced a change was needed. Studies under his direction had been going on in various institutions that were equipped for fast-neutron studies. Now Oppenheimer and his associates felt that further progress could be best achieved by concentrating everything in one central laboratory devoted exclusively to this work. Taking this step would not only eliminate waste and duplication, but it would also permit a freer exchange of ideas and provide for the centralized direction of all work, including studies of chemical, engineering, metallurgical, and ordnance

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problems that so far had received little or no attention.23

Groves first met Oppenheimer in early October while on his initial trip to familiarize himself with the atomic programs at the Universities of Chicago and California (Berkeley). The general heard a report from Oppenheimer on the eighth and the two men hit it off at once. Groves was interested in Oppenheimer’s proposed central laboratory and, a week later when the two met again with Marshall and Nichols on a Chicago-New York train, Groves asked Oppenheimer to come to Washington, D.C., to explore the idea. There, they talked with Arthur Compton and Vannevar Bush, and on 19 October Groves approved the decision to establish a separate bomb laboratory. Pleased with what had been accomplished and confident that Groves’ support in this step would “bear good fruit in the future,” Oppenheimer left immediately for Boston to brief Conant at Harvard, where the latter held the post of university president.24

Oppenheimer and Compton had spoken of placing the laboratory at the Tennessee site, or possibly in Chicago, but neither they nor General Groves were satisfied with these choices. For this most secret part of the secret Manhattan Project isolation and inaccessibility were most essential, and neither the Clinton Engineer Works nor Chicago offered these. In addition to the obvious requirements of a climate that would permit year-round construction, safety from enemy attack, ready transportation, and access to power, fuel and water, there were several other important considerations. The site would have to provide an adequate testing ground; it should be in a sparsely populated area, for reasons of safety as well as security; the land should be relatively easy to acquire; and it should already have sufficient buildings to house most of what was anticipated would be a comparatively small staff.25

Groves briefly considered two other sites. One near Los Angeles, he rejected on security grounds; the other, near the California-Nevada border, on the east side of the Sierra Nevada in the vicinity of Reno, he found unsatisfactory because it was too inaccessible and heavy snows would interfere with winter operations. He agreed with Oppenheimer that the region around Albuquerque, New Mexico, seemed to offer the most attractive possibilities. Oppenheimer owned a ranch in this vicinity, and his general knowledge of the countryside contributed considerably to making an accurate appraisal of the area. Air and rail service to Albuquerque were excellent; the climate was moderate throughout the year;

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and the area was not only isolated but also sufficiently far inland from the West Coast to be beyond any serious danger from the by now remote possibility of Japanese interference.

At the end of October, Maj. John H. Dudley, one of Colonel Marshall’s assistants who was familiar with the general area, made some preliminary surveys. He recommended a site at Jemez Springs, about 50 miles north of Albuquerque. (See Map 2.) Engineers from the Albuquerque District surveyed the site and, on 16 November, Groves met Oppenheimer and several others for a personal inspection of the area. They soon concluded, however, that the Jemez Springs site would not do; the land would be difficult to acquire and the nature of the terrain would prevent later expansion of the installation.26

Still hoping to find a suitable location in this general area, Groves and the others drove east and slightly north toward the tiny settlement of Los Alamos. This community, atop a high, level tableland, actually consisted of little more than the Los Alamos Ranch School for Boys. Otherwise the area was virtually uninhabited, with the nearest town located some 16 miles away. The school buildings and the complete isolation of the site were arguments in its favor. There appeared to be sufficient water, if the supply were carefully used, and all other characteristics seemed satisfactory. The only question was how willing the owners of the school would be to give it up to the Army. If they seriously opposed government acquisition, the resultant publicity would run counter to the secrecy desired by the project leaders.

While Groves and Oppenheimer headed back to Washington, D.C., Dudley and engineers of the Albuquerque District began a formal survey of a proposed site at Los Alamos. The desired area consisted of about 54,000 acres in Sandoval County, somewhat more than 20 miles airline distance northwest of Santa Fe, of which all but about 8,000 acres was in national forest land already owned by the United States government. Grazing lands and the Los Alamos Ranch School comprised the rest of the area. Because the school was having some difficulty getting instructors during the war and was in serious financial trouble, the owners were willing to sell. As for the grazing lands, there appeared to be no problem in acquiring them.

Even before the reports of this survey came in, General Groves had called a meeting in Washington to confer about the site with Oppenheimer, as well as with two of his scientific colleagues from California, Ernest Lawrence and Edwin McMillan, and with Arthur Compton. Then, on 23 November, with the reports in hand, Oppenheimer, Lawrence, and McMillan again inspected the area with Major Dudley and made recommendations on possible locations for

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Approach road to the Los 
Alamos ranch school for boys

Approach road to the Los Alamos ranch school for boys

laboratories and housing. “Lawrence was pleased by the site,” Oppenheimer reported to Groves, “and so, again, were we.”27

And so, again, was Groves. Two days later he approved the Los Alamos site and began steps to acquire the land. Right of entry to the heart of the site had already been obtained from the school director and, although the actual legal acquisition would take several months, Groves was able to authorize the Albuquerque District to proceed with construction on 30 November. The whole business was carried out, to use Oppenheimer’s words, “with unbelievable dispatch.”28

As with the Clinton Engineer Works, the Los Alamos site in the beginning also was referred to, for security reasons, as a demolition range – a somewhat ironic reference for a laboratory where an atomic bomb would be built. The site also had several names, the most common being Site Y, Project Y, Zia Project, Santa Fe, or simply, Los Alamos, its official title and the name by which it would be most widely known in the future.29

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Once the choice of Los Alamos had been made, events moved swiftly. “The last months of 1942 and early 1943,” recalled Oppenheimer later, “had hardly hours enough to get Los Alamos established.”30 Vigorously supported by Groves, Compton, Conant, and others, Oppenheimer launched an extensive recruitment program. He traveled all over the country, urging scientists of recognized ability to join the new laboratory. Restricted to revealing only what was absolutely necessary about the project, Oppenheimer faced no easy task trying to arouse the interest of scientists, technicians, and mechanics in the program, in indicating its sense of urgency, and in persuading them to sign up for work at a military post in the middle of the New Mexico desert, where they and their families might have to remain isolated for the duration of the war. Nevertheless, he was highly successful in these efforts. Recruits from Princeton, Chicago, California, Minnesota, Wisconsin, and other universities joined the program, the first contingent arriving at Los Alamos with Oppenheimer in March 1943, long before construction at the site was completed.

With the university scientists came their equipment: a cyclotron from Harvard, two more particle accelerators from Wisconsin, another from Illinois. Locating and securing this essential equipment was difficult enough; shipping it to New Mexico was an additional problem. “Everybody,” Oppenheimer later recalled, “arrived with truckloads of junk and equipment.” Under a contract with the University of California, erection of the first cyclotron began at Los Alamos in mid-April, and the first experiment was performed early in July. Already, Oppenheimer continued, “we were finding out things that nobody knew before.”31

Los Alamos was officially activated as a military establishment on 1 April 1943, with Oppenheimer as its scientific chief and Col. John M. Harman as its military head. It was unique among Manhattan Project installations in that it was established as a separate organization, directly responsible to General Groves. It came under the district engineer only for routine administrative matters. As its civilian director, Oppenheimer had broad authority and administrative responsibility. In charge of all scientific work as well as “the maintenance of secrecy by the civilian personnel under his control,”32 he was responsible only to Groves and Conant. This arrangement relieved Compton and the Metallurgical Laboratory of the responsibility for bomb design and construction and left them free to concentrate on plutonium production. The relations between Oppenheimer and Colonel Harman were based on close cooperation, rather than control. Harman, who also reported to Groves, had little or nothing to do with scientific matters. His primary responsibility was to oversee Los

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Alamos as a military reservation, including those housekeeping and guard functions necessary to support Oppenheimer’s program.33

The other major element in the administration of Los Alamos was the prime contractor, the University of California. Under a War Department contract, its role was largely to provide business management and technical procurement. For reasons of security, the university had no representative at Los Alamos with authority comparable to that of Oppenheimer or Colonel Harman.

Project leaders wanted to make the work and the living conditions at Los Alamos as attractive as possible; however, for reasons of security and safety, General Groves wished to maintain as much control as he could over the scientists. One idea he favored was to put key civilians in uniform as army officers. This plan seemed attractive to Oppenheimer but aroused strong opposition from many of the other scientists. The Military Policy Committee finally agreed to drop the idea for the period of initial experimental studies, but insisted that the scientific and engineering staff be composed entirely of commissioned officers when final experiments and the construction of the bomb began. Yet, when this time arrived, Project Y had grown so large that the plan was dropped as being impractical and unnecessary.

The most important personnel problem at Los Alamos was choice of a scientific director, and Oppenheimer’s appointment was no simple matter. While he had been the leader of the group studying the theoretical aspects of constructing atomic bombs, the Los Alamos program was to be a practical operation, and carrying it out would require considerable administrative and organizational abilities. The chiefs of the three other major Manhattan laboratories – Compton, Lawrence, and Urey – were all Nobel Prize winners. Oppenheimer was not, and there was some feeling among the scientists that this might disqualify him as head of the Los Alamos Laboratory. General Groves, while impressed with Oppenheimer’s great intellectual capacity, also was not entirely certain. Bush and Conant shared his hesitation; Lawrence, Compton, and Urey all indicated some reservations.

Nevertheless, a tentative decision in favor of Oppenheimer appears to have been made quite early, because neither Lawrence nor Compton – the only other candidates – could be spared from his own vital project. Oppenheimer’s appointment as “Scientific Director of the special laboratory in New Mexico” was formalized on 25 February in a letter to him from Groves and Conant;34 it did not,

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however, become final until mid-July because of security clearance problems. As was well-known to most of the project leaders, Oppenheimer had an extended history of supporting Communist-front organizations and causes and of association with Communists and fellow-travelers. Only through direct action by Groves was Oppenheimer, who was already at work in Los Alamos, finally cleared.35

Manhattan Project Organization and Operation

With the establishment of Los Alamos on 1 April 1943, the basic structure of the Army’s organization for administering the atomic bomb program was essentially completed. In the months that followed, detailed and sometimes substantial changes were made in that organization.36 For example, in mid-August, the Manhattan District moved from its temporary location in New York to permanent quarters at Oak Ridge, and Colonel Nichols, the deputy district engineer, replaced Colonel Marshall as district engineer when the Corps of Engineers reassigned Marshall to a post where he might receive his long overdue promotion to the rank of brigadier general.37 But these subsequent changes in key personnel and in the location of certain elements would not significantly affect the basic structure of the Manhattan Project, the term that by mid-1943 most accurately described the Army’s overall administrative organization for the atomic bomb program.

The administrative elements that comprised the Manhattan Project

Chart 1: Organization of 
the Manhattan Project, April 1943

Chart 1: Organization of the Manhattan Project, April 1943

Sources: MDF1, Bk. I, Vol. 12, App. C21, DASH; Org Charts, U.S. Engrs Office, MD, 27 Jan and 1 Apr 43. OROO.

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Manhattan Project Emblem 
(unofficial, circa 1946)

Manhattan Project Emblem (unofficial, circa 1946)

were divided into two major categories: those that functioned as integral elements of the Manhattan District and those that operated outside the structure of the District, mostly in the area of high-level policymaking or in the executive direction of the atomic project (Chart 1). The central element in the high-level administrative hierarchy of the Manhattan Project was General Groves’ personal headquarters. The headquarters organization consisted of only a very small group: Groves; Mrs. Jean O’Leary, his secretary who served as his administrative assistant in lieu of an executive officer; and several clerical employees.38 Shortly after becoming Manhattan commander, and knowing from experience that any effort on his part to expedite important project activities would require access or negotiations with government agencies and officials, Groves decided to locate his personal headquarters in rooms adjacent to those already occupied by the Manhattan District’s Washington Liaison Office in the New War Department Building on Virginia Avenue, a few blocks from the White House. Considered at first to be temporary, time proved that location especially well suited to the project’s need, and Groves’ office remained there for the duration of the Army’s administration of the atomic bomb program.

When Groves replaced Marshall as the Army’s project director, the Engineers chief pointedly removed himself from any further administrative responsibility for the program. Although the Corps of Engineers continued to assist the project, the latter functioned as a basically independent organization, with the Manhattan commander having responsibility to the Army Chief of Staff and Secretary of War and through them to the President.

Committees continued to play an important role in guiding, advising, and instructing the Army administrators of the project and, to some extent, limiting their authority. Beginning in late 1942, the group most involved in providing guidance for the day-to-day administration was the Military Policy Committee, which derived its authority for policymaking from the Top Policy Group. Although the group never formally convened, it continued, as during the OSRD period, to review and ratify all major policies and decisions relating to development and employment of atomic energy for military purposes in World War II. The OSRD S-1 Executive Committee also continued to function as an advisory group until the transfer of most atomic activities from the

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Mrs. Jean O’Leary reviewing project reports with General Groves

OSRD to the Army was completed in mid-1943.39

Responsibility for execution of the plans, policies, and decisions made by the various advisory groups of the Manhattan Project devolved first upon General Groves and through him upon the Manhattan District. Groves, as officer in charge of the atomic bomb program for the Army, exercised command authority over the District, but he was not its chief executive officer. That position was held by the district engineer, who reported to Groves.

The district engineer presided over an organization that was, as it emerged in mid-1943, similar in many respects to the engineer districts that had been formed by the Corps of Engineers in the past to carry out special assignments (Chart 2). Its administrative elements were grouped into two major categories: operating units, which were involved primarily in the day-to-day monitoring of contractor operations; and staff units, which were engaged in overseeing and providing services.

Chart 2: Organization of 
the Manhattan District, August 1943

Chart 2: Organization of the Manhattan District, August 1943

Source: Org Chart, U.S. Engrs Office, MD, 15 Aug 43, Admin Files, Gen Corresp, 020 (Med-Org), MDR.

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In both types of units, military personnel headed virtually all administrative elements down to the section level, although many of the District employees filling positions that required special knowledge or training were civil service workers. The chiefs of each of these units reported directly to the district engineer, who functioned with the assistance of a small headquarters group comprised of an executive officer, two administrative assistants, and legal and medical advisers.

Operating units, each headed by a unit chief or an area engineer, were formed to monitor each of the major contractor-operated activities. The number and precise character of these operating units varied considerably due to the quantity and type of contract operations under District supervision. Thus, in the early period of the District’s operation the units conformed to the emphasis on construction activities, whereas later they reflected the shift to plant-operating activities. By the time of the District headquarters move in August 1943 from New York City to Oak Ridge, five major operating units – Madison Square Area, Hanford Engineer Works, Clinton Engineer Works, New York Area, and Special Products – had been established.

The elements concerned with overseeing project operations and services were divided among seven major staff components: the Y-12 (electromagnetic), K-25 (gaseous diffusion), X-10 (plutonium), and P-9 (heavy water) unit chiefs; and the Technical, Service and Control, and Administrative Divisions. The four unit chiefs were responsible for the overall supervision of the construction and operations phases of the production processes. The Technical Division had responsibility for the major contractor-operated research and development programs at Columbia and the Universities of California (Berkeley), Chicago, and Rochester;40 the Service and Control Division, for control functions, intelligence and security matters, labor relations, safety, and military personnel; and the Administrative Division, for procurement and contracts, fiscal matters, civilian personnel, priorities and materials, correspondence and the library, classified files and mail and records, and the District’s Washington Liaison Office. Additionally, the latter division provided the Los Alamos Laboratory with specified routine services.

With the rounding out of the Army’s organization for administration of the American atomic energy program in mid-1943, General Groves and his District staff were in a much firmer position to convert the OSRD-inherited research and development organization into an industrial complex for producing fissionable materials for atomic weapons. During the months that followed, the Army had to make further internal reorganizations to meet the new requirements resulting from the shift from plant construction to plant-operating activities and the addition of new facilities.41 But with Groves at the helm,

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carrying out the Military Policy Committee’s decisions and overcoming seemingly insurmountable obstacles, the atomic project moved ahead.