United States and weapons of mass destruction

United States of America
United States of America
Nuclear program start date	21 October 1939
First nuclear weapon test	16 July 1945
First thermonuclear weapon test	1 November 1952
Last nuclear test	23 September 1992
Largest yield test	15 Mt (1 March 1954)
Total tests	1,054 detonations
Peak stockpile	32,040 warheads (1967)
Current stockpile	5,044 total (2024)
Current strategic arsenal	1,670 (2023)
Cumulative strategic arsenal in megatonnage	≈820 (2021)
Maximum missile range	13,000 km (8,078 mi) (land); 12,000 km (7,456 mi) (sub)
NPT party	Yes (1968, one of five recognized powers)

The United States is known to have possessed three types of weapons of mass destruction: nuclear, chemical, and biological weapons. The U.S. is the only country to have used nuclear weapons on another country, when it detonated two atomic bombs over two Japanese cities of Hiroshima and Nagasaki during World War II. It had secretly developed the earliest form of the atomic weapon during the 1940s under the title "Manhattan Project".^[4] The United States pioneered the development of both the nuclear fission and hydrogen bombs (the latter involving nuclear fusion). It was the world's first and only nuclear power for four years, from 1945 until 1949, when the Soviet Union produced its own nuclear weapon. The United States has the second-largest number of nuclear weapons in the world, after the Russian Federation.^[5]^[6]