Atomic Energy Commission Is Established Summary

  • Last updated on November 10, 2022

President Harry S. Truman signed a law establishing the Atomic Energy Commission as the nation’s primary policy-making agency for the development of nuclear energy.

Summary of Event

Prior to 1942, the U.S. government, acting primarily through the Office of Scientific Research and Development Office of Scientific Research and Development, U.S. (OSRD), had spent modest sums in underwriting some of the nuclear research being carried on at various colleges, including Princeton University, Columbia University, the University of Chicago, and the University of California, Berkeley. Since the actual production of atomic weapons would require dedicated research labs and large facilities where uranium of weapons-grade quality could be separated from uranium ore, construction would be a major element in the development of nuclear weapons. [kw]Atomic Energy Commission Is Established (Aug. 1, 1946) [kw]Energy Commission Is Established, Atomic (Aug. 1, 1946) [kw]Commission Is Established, Atomic Energy (Aug. 1, 1946) Atomic Energy Commission, U.S.;establishment Nuclear energy;regulation Atomic Energy Act (1946) McMahon Act (1946)[Macmahon Act] Atomic Energy Commission, U.S.;establishment Nuclear energy;regulation Atomic Energy Act (1946) McMahon Act (1946)[Macmahon Act] [g]North America;Aug. 1, 1946: Atomic Energy Commission Is Established[01810] [g]United States;Aug. 1, 1946: Atomic Energy Commission Is Established[01810] [c]Organizations and institutions;Aug. 1, 1946: Atomic Energy Commission Is Established[01810] [c]Laws, acts, and legal history;Aug. 1, 1946: Atomic Energy Commission Is Established[01810] [c]Energy;Aug. 1, 1946: Atomic Energy Commission Is Established[01810] [c]Government and politics;Aug. 1, 1946: Atomic Energy Commission Is Established[01810] Groves, Leslie Richard McMahon, Brien May, Andrew Jackson Johnson, Edwin C. Truman, Harry S. [p]Truman, Harry S.;nuclear technology

In 1942, the U.S. Army was therefore given the authority to build the necessary facilities and direct the nuclear program that became known as the Manhattan Engineer District, or simply the Manhattan Project Manhattan Project . To head it, the Army appointed General Leslie Richard Groves, a hard-driving engineer and expert in construction. Groves remained in command until the Atomic Energy Commission officially began operations.

Although the results of the wartime nuclear program are well known, the development of an atomic bomb was only one aspect of the new field of nuclear energy. Eminent scientists believed that the United States needed to be prepared to maintain leadership in nuclear research, to develop the potential of nuclear energy as a source of industrial power, and, if necessary, to stockpile fissionable materials for both military and industrial use. Executives of corporations such as Union Carbide, Tennessee Eastman (a subsidiary of Eastman Kodak), Du Pont, and Westinghouse also participated in discussions about the future uses of nuclear energy.

When World War II ended, scientists and others who perceived the unique nature of nuclear energy rallied to the idea that efforts should be made to secure mechanisms for the international control of atomic energy. The failure of the resulting negotiations guaranteed that the United States and the Soviet Union would become rivals in atomic energy. With Cold War tensions already growing, the Soviet Union made every effort to move rapidly ahead in the field. The United Kingdom already had the capability to progress in applications of nuclear energy, and other nations were sure to become involved. Although disputes over priorities and timing were inevitable, there was considerable agreement among military, scientific, and industrial leaders that the United States needed to remain preeminent in nuclear energy.

As early as 1944, officials in the OSRD drafted a bill establishing guidelines for postwar government control of nuclear energy. The OSRD proposal envisioned a twelve-member commission appointed by the president. The commission would have the power to regulate transfers of fissionable materials and to oversee the construction and operations of all production plants and experiments involving significant amounts of fissionable material, such as uranium 235 and plutonium. The issue of postwar government involvement, however, was by no means cut and dried; questions remained about numerous issues, including security procedures, patents resulting from government-funded research, and the extent of government control needed.

On October 3, 1945, President Harry S. Truman sent a message to Congress setting forth the broad principles that the administration wished to pursue in its quest for the domestic and international control of the atom. The ideas in Truman’s message were based on the plans prepared by the OSRD and modified in important ways by Kenneth Royall Royall, Kenneth and William Marbury Marbury, William , War Department lawyers. Following Truman’s announcement, the bill that the two attorneys drafted was directed to the military affairs committees of the House and the Senate, chaired respectively by Andrew Jackson May of Kentucky and Edwin C. Johnson of Colorado, both Democrats. The enabling legislation that the two men agreed to sponsor became known as the May-Johnson Bill May-Johnson Bill (1945)[May Johnson Bill] .

Speedy passage of the bill was not forthcoming, however, for nuclear scientists and concerned members of the media convinced Congress to hold careful hearings on a matter of such consequence. Much of the testimony called for limitations on military involvement in the control and direction of nuclear energy. Scientists who had chafed under wartime regulations imposed by Groves labored to see security restrictions kept to a minimum, for they agreed that the free exchange of ideas was vital to progress in their disciplines. Within Congress, opponents of the May-Johnson Bill succeeded in transferring the hearings to the newly established Senate special committee chaired by Brien McMahon of Connecticut. Under McMahon, who sympathized with the opponents of May-Johnson in important ways, the hearings continued for several months. In response to mounting criticism of the May-Johnson Bill, Truman quietly withdrew his support of it and some months later endorsed the McMahon Bill instead.

Compromises began to be made. The May-Johnson Bill tilted toward military control, while the McMahon Bill favored civilian control but was amended to allow the military ample influence in shaping weapons development. There was, however, substantial agreement that the government should be authorized to control nuclear facilities and to set nuclear policy in its civilian as well as military aspects. Paradoxically, as historians George Mazuzan and J. Samuel Walker have pointed out, many of the most unyielding advocates of government monopoly during the congressional hearings were political conservatives who had spent years railing against the New Deal and government involvement in the economy.

Both bills therefore envisioned the establishment of a government agency to continue in peacetime what the Manhattan Project had begun in wartime. The new agency, which was named the Atomic Energy Commission (AEC), would also chart the future course of nuclear policy.

As differences were narrowed, the bill that took shape in the summer of 1946 gave the AEC exclusive authority over the development and applications of atomic energy, ownership of all fissionable materials (amended by the 1954 Atomic Energy Act) and the facilities for producing them, and control of patents already owned by the government, in addition to any that might be developed during research funded by the government. There were also provisions for security checks on all individuals who worked for the AEC and its civilian contractors.

Five commissioners appointed by the president for two-year terms (later changed to staggered five-year terms) would determine AEC policy, while daily operations would be directed by a general manager, also a presidential appointee. To ensure the military’s continued involvement in policy decisions, the bill called for a Military Liaison Committee that would have direct access to the civilian heads of the armed services. In addition, eminent scientists and engineers were to serve on the General Advisory Council (in practice, the AEC itself had one seat for a scientist). To maintain legislative oversight of the powerful new executive agency, the bill established an eighteen-member Joint Committee on Atomic Energy Joint Committee on Atomic Energy . Each house of Congress would receive nine seats on the committee. No more than five seats in each house could go to members of one party.


Although President Truman signed the enabling legislation for the AEC on August 1, 1946, the commission did not begin operations until midnight of December 31, when it received from the Manhattan Project control of the principal facilities developed during World War II. Weeks, however, had already been devoted to preparing for the official transfer. The inherited facilities included the bomb lab at Los Alamos, New Mexico, and large sites and plants at Oak Ridge, Tennessee, and Hanford, Washington. The principal activity at Oak Ridge was the separation of uranium so that U-235 (the fissionable isotope of uranium) could be made available for weapons research and manufacture. Plutonium (an artificially processed fissionable material) was produced at Hanford.

The AEC began operations with about four thousand civilian employees, two thousand military personnel, and thirty-eight thousand civilians working for it through its prime contractors. Union Carbide and General Electric would manage the production plants at Oak Ridge and Hanford, respectively, while the University of California continued to direct the laboratory at Los Alamos.

Although the Manhattan Project had lost momentum in the demobilization that followed World War II, Groves had kept the project functioning and had even committed funds to develop still more facilities, including laboratories at Argonne, Illinois, and Brookhaven, New York. The AEC decided that Argonne would concentrate on the development of reactors for the generation of electricity and for submarine propulsion, while Brookhaven’s mandate would be limited to peaceful uses of the atom and to basic research in such fields as radiation biology and medicine.

Both Argonne and Brookhaven were designated as national laboratories. Several northeastern universities were authorized to form a consortium to manage Brookhaven, while the University of Chicago managed Argonne. The AEC also funded research done at individual campuses. The actual testing and construction of reactors would soon lead to the opening of a national reactor testing site near Idaho Falls, Idaho.

The AEC empire would grow even larger as the 1940’s drew to a close, for Cold War anxieties helped bring about U.S. determination to expand its nuclear arsenal. A fourfold increase in the AEC’s budget between 1947 and 1952 revealed the extent of the nation’s alarm. Truman’s decision to authorize development of a hydrogen bomb further increased the demand for fissionable materials and led to the building of additional AEC facilities. A second weapons lab was constructed at Livermore, California. Moreover, hundreds of private corporations were subcontracted to join the nuclear weapons program.

In 1950, the AEC and the Department of Defense jointly selected a site in Nevada as the proving grounds for the many tests that would be held as new types of nuclear weapons were readied. (Thermonuclear weapons were tested at a Pacific Ocean site.) The magnitude of the AEC operations was described in 1952 by Time magazine as a “land area half again as big as Delaware, growing more rapidly than any great U.S. business ever did. Its investment in plant and equipment . . . makes it bigger than General Motors.” Radioactive wastes were produced at all the AEC sites; while it was AEC policy to dispose of these wastes in accordance with the safety standards that existed at the time, there was always the possibility that new findings would reveal these standards to be inadequate or that something unforeseen could occur while wastes were being handled.

From its beginning, the AEC had a complex and often contradictory mission. Originating at the dawn of the Cold War, the agency emphasized research in nuclear weaponry, testing of new designs, and production of fissionable materials for the military. The agency’s charter also addressed the development of commercial applications of nuclear power and dealt with the funding of research into the health and environmental effects of radiation. By the early 1950’s, the growing output of nuclear warheads and the testing of new designs demonstrated that the AEC was fulfilling its mandate to design and help produce weaponry. Whether it could fulfill its other roles equally well remained to be seen, but such progress would not be an unmixed blessing. The development of commercial nuclear power meant that more reactors would be constructed and placed at new locations throughout the United States. Once commercial nuclear power plants became a reality, contractors would be charged with handling fissionable materials and nuclear wastes.

These developments and an increasing awareness that the regulatory and promotional aspects of the AEC’s work ought to be separated led to initiatives for legislative reform. In 1974, pursuant to the passage by Congress of the Energy Reorganization Act, the AEC ceased to exist, as the regulatory functions of the AEC were vested in a new Nuclear Regulatory Commission and its promotional functions given to a new Energy Research and Development Administration, which was later absorbed into the U.S. Department of Energy. Atomic Energy Commission, U.S.;establishment Nuclear energy;regulation Atomic Energy Act (1946) McMahon Act (1946)[Macmahon Act]

Further Reading
  • citation-type="booksimple"

    xlink:type="simple">Anders, Roger M., ed. Forging the Atomic Shield: Excerpts from the Office Diary of Gordon E. Dean. Chapel Hill: University of North Carolina Press, 1987. A former law partner of Brien McMahon, Dean became the AEC’s second chairman in 1950. The Cold War was then at its height, and Dean’s diary provides insight into the concerns of the AEC.
  • citation-type="booksimple"

    xlink:type="simple">Duffy, Robert J. Nuclear Politics in America: A History and Theory of Government Regulation. Lawrence: University Press of Kansas, 1997. A study of government policy and regulation of the nuclear power industry in the United States. Chapters include “Subgovernment Dominance, 1945-65,” “Redefining Nuclear Power,” and “The Demise of the AEC.”
  • citation-type="booksimple"

    xlink:type="simple">Hewlett, Richard G., and Oscar E. Anderson, Jr. The New World, 1939-1946. Vol. 1 in A History of the United States Atomic Energy Commission. University Park: Pennsylvania State University Press, 1962. Based on research in archives, published sources, and numerous interviews, this book provides a reliable study of the wartime development of the Manhattan Project as well as the congressional maneuvers that resulted in the establishment of the AEC.
  • citation-type="booksimple"

    xlink:type="simple">Hewlett, Richard G., and Francis Duncan. Atomic Shield, 1947-1952. Vol. 2 in A History of the United States Atomic Energy Commission. University Park: Pennsylvania State University Press, 1969. Begins with the confirmation hearings of the original five appointees to the AEC and concludes with the detonation of the world’s first thermonuclear device at Eniwetok in the Pacific late in 1952.
  • citation-type="booksimple"

    xlink:type="simple">_______. Nuclear Navy, 1946-1962. Chicago: University of Chicago Press, 1974. Provides a reliable overview of the U.S. Navy’s efforts to develop and utilize nuclear reactors as a source of propulsion. Surveys the people involved in the Navy’s efforts.
  • citation-type="booksimple"

    xlink:type="simple">Hewlett, Richard G., and Jack M. Holl. Atoms for Peace and War, 1953-1961: Eisenhower and the Atomic Energy Commission. Berkeley: University of California Press, 1989. Much more concerned with safety issues than the two previous volumes listed above. An “Essay on Sources” by Roger M. Anders will point the way to many books dealing with nuclear topics.
  • citation-type="booksimple"

    xlink:type="simple">Lilienthal, David Eli. Change, Hope, and the Bomb. Princeton, N.J.: Princeton University Press, 1963. A distinguished public servant, Lilienthal was the first chairman of the AEC. This extended essay presents his thoughts on issues such as nuclear disarmament, nuclear fuels versus fossil fuels, and peaceful uses of the atom.
  • citation-type="booksimple"

    xlink:type="simple">_______. The Journals of David E. Lilienthal. Vol. 2 in The Atomic Energy Years, 1946-1950. New York: Harper & Row, 1964. Lilienthal’s journal describes the pressures he felt from the military, the media, and congressional critics as the AEC’s first chairman.
  • citation-type="booksimple"

    xlink:type="simple">Mazuzan, George T., and J. Samuel Walker. Controlling the Atom: The Beginnings of Nuclear Regulation, 1946-1962. Berkeley: University of California Press, 1985. Complements the official history of the AEC by analyzing government efforts to define radiation hazards and to provide safeguards.
  • citation-type="booksimple"

    xlink:type="simple">Pfau, Richard F. No Sacrifice Too Great: The Life of Lewis L. Strauss. Charlottesville: University Press of Virginia, 1984. A hard-driving, successful, and opinionated businessman, Strauss worked in the Navy Department during World War II and later became involved in nuclear affairs as a member of the AEC and, later, as its chairman. He often disagreed with Lilienthal.
  • citation-type="booksimple"

    xlink:type="simple">Walker, J. Samuel. Containing the Atom: Nuclear Regulation in a Changing Environment, 1963-1971. Berkeley: University of California Press, 1992. Continues the story of government-sponsored research in radiation hazards and efforts to provide controls.
  • citation-type="booksimple"

    xlink:type="simple">_______. A Short History of Nuclear Regulation, 1946-1999. Washington, D.C.: U.S. Nuclear Regulatory Commission, 2000. A seventy-page history of the Atomic Energy Commission and the Nuclear Regulatory Commission. Available at

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