President Roosevelt, along with top officials, created the Manhattan Project for the development of nuclear weapons. This directive required building a massive industrial complex which spanned the United States in over 350 facilities. The diverse skills of many different types of workers were needed – from those in the uranium mines all the way to Ivy League scientists. By 1945, the government said the size of the complex was equivalent to the U.S. automobile industry.

Even after the end of WWII, the production of nuclear weapons continued for the defense of the U.S. Taxpayers spent over $5.8 trillion dollars during the first sixty years to develop nuclear weapons that the military maintained in missiles, bombers, and submarines. Over 700,000 highly skilled men and women directly contributed to the effort.

Development of nuclear weapons began in Nazi Germany in 1938. After Albert Einstein wrote a letter to President Roosevelt about the need to build a similar weapon to defend the U.S., research began with complete confidentiality in 1940. In 1942, the Manhattan Project, which was the code name for the nuclear program, began to build plants, laboratories, and manufacturing facilities across the U.S. Most workers were sworn to secrecy, and many did not even know the details of what they were building until the first nuclear weapons were used on Hiroshima and Nagasaki during World War II. After the war, advancements in nuclear weapons continued and other countries such as the Soviet Union developed their own munitions.  The Arms Race continued through the 50s and 60s with the U.S. and Soviet Union stockpiling atomic weapons. At the height of nuclear development, there were hundreds of facilities in the U.S. involved with mining, refining, fabrication, weapon assembly, and testing.  After many above ground and underground tests, the after effects of the radioactive fallout became clear; therefore many treaties were put in place to reduce the number of nuclear arms. From 1942 to the present day, over 700,000 American men and women have worked in the nuclear weapons complex to maintain our nation’s deterrent.

In 1938, nuclear fission was discovered by Otto Hahn, Lisa Meitner, and Fritz Strassman in Nazi Germany.  This discovery was announced by Niels Bohr during his visit to the U.S.  Several months later, Albert Einstein wrote a letter to President Franklin Roosevelt detailing the possibility of an atomic weapon being developed by Germany using nuclear fission.  The letter warned the president to immediately build a similar weapon, or the future of democracy would be at risk. A month later in September 1939, WWII began with Germany invading Poland.

Nuclear research in the U.S. began in 1940, although it was kept very quiet and confidential. President Roosevelt signed a document in 1941 to approve the mission of the atomic program and selected to have the U.S. Army Corps of Engineers run the operation.  They had experience with management of large-scale construction projects which included plants, laboratories, and manufacturing facilities. In December, Japan attacked Pearl Harbor and the U.S. entered WWII, so the assignment intensified.

Roosevelt’s Top Policy Group received approval for a budget of $54 million for continued research in June 1942.  By September 1942, the army appointed General Leslie R. Groves as the director of the Manhattan Project.  Almost overnight, towns like Oak Ridge, Tennessee and Los Alamos, New Mexico transformed into secret cities to further the development of nuclear weapons.  It was named the Manhattan Project due to the early research done at Columbia University and the first headquarters for the project, both located in Manhattan.

Scientists from all over the U.S. worked tirelessly at these secret facilities and universities to work on the nuclear fission Albert Einstein wrote about back in 1938.  A breakthrough occurred in December 1942 when Enrico Fermi produced the first sustainable nuclear fission reaction at the University of Chicago. In April 1943, J. Robert Oppenheimer, a physicist from the University of California, Berkeley, assembled a team of scientists in Los Alamos to develop an atomic bomb.  Oppenheimer would later be called the “father of the atomic bomb” for his role in the Manhattan Project.  Progress continued in ’43 and ’44 on the design and functionality of the bomb with the separation of uranium isotopes and the production of plutonium.

In April of 1945, President Roosevelt died.  President Harry S. Truman took over and became aware of the Manhattan Project which had been undisclosed for so long.   Just a month later, Germany surrendered and the war ended in Europe, but America continued to fight Japan.  In July 1945, the U.S. detonated the first atomic device at the Trinity Site in New Mexico.   Three weeks later, the U.S. dropped the first atomic bomb, known as Little Boy, on Hiroshima, Japan.  The U.S. dropped a second bomb, known as Fat Man, on Nagasaki, Japan three days later.  Japan surrendered and WWII ended, but development of nuclear weapons continued.  In fact, production increased as the Cold War with the Soviet Union began.

The Atomic Energy Commission (AEC) took over the development of nuclear weapons after WWII.  By 1948, AEC started offering incentives for mining of uranium sources so the U.S. could continue production as other countries were developing their own nuclear programs, especially the Soviet Union.  A boom in uranium mining took place in the Southwest.  The Soviet Union detonated their first atomic weapon in August 1949. This was the start of The Arms Race.

In 1950 President Truman announced the U.S. would develop fusion weapons.  In 1951, the first above ground detonation occurred.  Throughout 1951-1952, many facilities were opened to forge ahead with production in South Carolina, Texas, Ohio, Colorado, California and Kentucky.   By late 1952, the U.S. had detonated the first hydrogen (fusion) weapon in the South Pacific.  Less than a year later, the Soviet Union detonated its first fusion weapon.

In the summer of 1957, the U.S. instituted the Plowshare Program to develop peaceful uses for nuclear weapons.  This program ended in 1977 due to many negative impacts.  Fall 1957 was the first underground nuclear detonation at the Nevada Test Site.  The first Intercontinental Ballistic Missile (ICBM) was deployed in Montana in October 1958.

The Cuban Missile Crisis of 1962 was a dangerous time when the U.S. and Soviet Union were ready to go to war against each other.  Both knew the other had nuclear weapons and could cause destruction of mass proportions. Concern was rising regarding the radioactive fallout in the atmosphere as well as in the water.   In 1963, the Soviet Union, United Kingdom, and the United States signed the Strategic Arms Limitation Talks (SALT) treaty prohibiting the testing of nuclear weapons except underground.

In late 1974, the U.S. and Soviet Union continued to limit their arsenals with the SALT treaty.  1990 is the last known nuclear test by the Soviets.  The U.S. followed suit and conducted its last nuclear test in 1991. From the late 80’s to the mid-90’s many U.S. nuclear facilities were consolidated or shut down, but several are still in operation throughout the U.S.

Today there are many countries known to have successfully detonated nuclear weapons, including the U.S., France, United Kingdom, Russia, India, Pakistan, China, North Korea, Israel, and South Africa.  There are also other countries attempting to procure atomic arms, such as Iran.  There is, however, a treaty that has been in place since 1996 and is signed by many countries with nuclear powers banning the testing of the weapons.