Operation Crossroads: First US Postwar Nuclear Tests at Bikini Atoll

Date

July–August 1946

Category

Military & conflict

Region

Bikini Atoll, Marshall Islands (Oceania)

Era

Contemporary

Significance

Operation Crossroads was a pair of nuclear weapon tests conducted by the United States at Bikini Atoll in the Marshall Islands in the summer of 1946, the first nuclear detonations since the Trinity test and the wartime bombings of 1945 and the first to be publicly announced and witnessed by international observers.

Carried out by Joint Army/Navy Task Force One under Vice Admiral William H. P. Blandy, the operation was designed to study the effects of nuclear weapons on naval vessels, assembling a target fleet of roughly 95 warships in the lagoon and mobilising about 42,000 personnel. The first shot, Able, was an airburst detonated on 1 July 1946, while the second, Baker, exploded underwater on 25 July 1946; both used 23-kiloton plutonium 'Fat Man' devices, and Baker produced iconic images of a nuclear column and unexpectedly severe radioactive contamination, later called the world's first nuclear disaster. To clear the test site, the US Navy had relocated the atoll's 167 inhabitants to Rongerik Atoll in March 1946, beginning a long exile that left the Bikinians as 'nuclear nomads' as their home remained uninhabitable. A planned third test, Charlie, was cancelled because of the lingering radiation, and the tests marked the opening of the Marshall Islands' role as a long-term US nuclear testing ground and a touchstone in debates over the nuclear arms race and indigenous displacement.

Empires active in July–August 1946

• Soviet Union
  1922 CE – 1991 CE
• Empire of Japan
  1868 CE – 1947 CE
• French Colonial Empire (Second)
  1830 CE – 1962 CE
• British Empire
  1583 CE – 1997 CE
• Spanish Empire
  1492 CE – 1976 CE
• Portuguese Empire
  1415 CE – 1999 CE

Related military & conflict events

• Creation of Israel and the 1948 Arab–Israeli War
  14 May 1948 (war May 1948 – July 1949)
• Korean War
  25 June 1950 – 27 July 1953
• Cuban Missile Crisis
  16–28 October 1962
• Fall of Saigon and reunification of Vietnam
  30 April 1975 (reunified 1976)
• Khmer Rouge Seize Cambodia and Declare Year Zero
  1975
• The Rwandan genocide against the Tutsi
  7 April – 19 July 1994

Further reading

A History of the Pacific Islands

The wider story

A History of the Pacific Islands

Steven Roger Fischer

The standard accessible overview of Oceania from settlement to the modern era.

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