'Test Able' on 1 July 1946 at Bikini Atoll:
First nuclear test after Hiroshima and Nagasaki

1 July 1946 - 'Test Able',
Bikini Atoll

Able’s cloud boiled up to a height of 11 kilometres.

On 1 July 1946, the United States conducted the first nuclear test after World War II. The explosion took place at the Bikini Atoll lagoon, situated in the Marshall Islands in the Pacific Ocean. Test Able was to be the first of a series of 67 tests in the atoll and the second U.S. nuclear test of over a thousand to follow.

The explosion of the fission bomb, largely identical to the weapon used in the attack on Nagasaki on 9 August 1945, occurred 158 metres above sea level and had a yield of 23 kilotons. The main aim was to test the effects of nuclear weapons on ships. To that end, a fleet of 78 vessels, many of which had been captured during World War II, was anchored in the lagoon. The blast sunk only five of them, leaving another 14 seriously damaged.

The target fleet of 78 ships.

The irradiation consequences, however, were largely underestimated. Marines were ordered to board the vessels shortly after the explosion to attempt to decontaminate the ships by scrubbing the decks, exposing them to high doses of radioactivity. After these efforts proved largely ineffective, many of the ships were subsequently abandoned and sunk in the Pacific Ocean.

57 animals were placed aboard the target ships (U.S. Archives).

Apart from experimenting with the naval array, the test was used to investigate the effect of nuclear explosions on living beings. Fifty-seven animals were placed on the targeted ships, of which roughly a third died directly from the blast or from lethal radiation doses. This triggered numerous protests in the United States – rallying public opinion against nuclear testing for the first time.

Sequence from the award winning documentary Trinity and Beyond (The Atomic Bomb Movie) by Peter Kuran:

The campaign by the late Dr Louise Reiss exposed the global contamination by nuclear testing fallout.

It was only after the United States (joined by the Soviet Union from 1949) had conducted several hundred more atmospheric nuclear tests, irradiating practically every living being on Earth, that public pressure increased, leading to the adoption of the 1963 Partial Test Ban Treaty. Dr Louise Reiss and her Baby Tooth Survey had played a significant role. While this treaty drove most nuclear testing underground, it did little to constrain the development of weapons.

Only the 1996 Comprehensive Nuclear-Test-Ban Treaty (CTBT) bans all forms of nuclear testing. Although 183 countries have signed the Treaty, of which 164 have also ratified, it must be ratified by 44 specific countries – those holding nuclear technology at the time of its negotiation - to enter into force. Thirty-six countries have already done so, including the nuclear weapon possessors France, Russia and the UK. The remaining eight are China, Egypt, Iran, Israel and the United States, which have already signed the CTBT, as well as India, Pakistan and the Democratic People's Republic of Korea, which have yet to sign and ratify.

Islanders had been asked to "temporarily" leave Bikini "for the good of mankind and to end all world wars" (U.S. Archives)

In 1997 the International Atomic Energy Agency reported that the Bikini Atoll was still uninhabitable. Read more on the health and environmental impacts of the United States’ nuclear testing programme and the Marshallese claims for compensation.


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Next featured nuclear test:

6 July - 'Sedan' - massive crater, massive contamination