The largest nuclear weapon ever detonated by the United States went off on the evacuated Bikini Atoll in the Marshall Islands on March 1, 1954.* Nearly a thousand times the strength of the atomic bombs that the U.S. dropped on the Japanese cities of Hiroshima and Nagasaki, which killed hundreds of thousands of people, Castle Bravo was one of 67 nuclear weapons tested by the U.S. military in and around the Pacific Island chain from 1946 to 1958.
At the time, the United Nations had given the U.S. administrative authority over the Marshalls, 29 coral atolls made up of 1,156 individual islands and islets. The U.S. had responsibility for, among other things, guarding the health of the islands’ inhabitants and protecting them against loss of land and resources.
But the U.S. testing resulted in entire islands vaporized and others rendered uninhabitable due to radioactive fallout, displacing thousands of Marshallese people — many of whom out of necessity now live in the country whose government uprooted them from their homes, but where they are not citizens. The radioactive fallout from the tests led to cancer, birth defects, and diseases and chronic health conditions that persist today. The one atoll the U.S. attempted to clean up, Enewetak, still has millions of cubic square feet of radioactive waste — including lethal plutonium — housed in a concrete structure called Runit Dome that’s threatened by rising seas from climate change. And 75 years after the nuclear testing began, the U.S. has still not publicly released all the information it has about its extent or effects.