Sun in a Bottle - Charles Seife [30]
As radioactive as the Nagasaki and Hiroshima bombs were, the multimegaton blasts of fusion weapons were much worse. The world got a taste of their deadly potential in 1954 with the Castle Bravo nuclear accident.
At 6:45 AM on March 1, 1954, the United States detonated a hydrogen bomb; ground zero was a reef in Bikini atoll. The explosion was much bigger than expected—fifteen megatons, the largest explosion yet—roughly equivalent to one thousand Hiroshima-sized bombs. The fireball pulverized the coral reef, sending pieces flying thousands of feet into the air.
By 8:00 AM, “pinhead-sized white and gritty snow” began to shower the American fleet observing the test. This was highly radioactive fallout. The radiation levels on the ships rose rapidly, and the fleet immediately steamed south to escape, but not before more than twenty sailors received radiation burns, and thousands more had been exposed to fallout. Fifteen minutes later, the snow began to fall on a Japanese fishing vessel, the Daigo Fukuryu Maru. The whole crew was exposed. (The captain died shortly thereafter, the first person killed by a fusion weapon.)22 Within hours, the eastward-drifting cloud dropped fallout on the Rongelap atoll and some other nearby, inhabited islands. The navy evacuated more than six hundred people, many of whom developed “raw, weeping lesions” from the radiation.
It was a public relations nightmare. AEC chairman Lewis Strauss tried to reassure the public that the island natives were “well and happy,” but it was hard to hide the truth, and the photographs of burned islanders, from the press. The newspapers had lurid details; they even told of how the ship’s cargo of radioactive fish was put up for sale on the Japanese market. (A New York Times subhead, “Radioactive Fish Sought In Japan,” seemed like something from a B movie. It was hardly good press for American nuclear scientists.)23
The Castle Bravo accident marked a turning point in the perception of nuclear tests. Every time such a test weapon exploded, it spewed radioactive ash into the atmosphere, and scientists noticed that the world was becoming increasingly radioactive as a result. As tests continued, the problem got worse. Scientists were particularly concerned about a radioactive isotope of the metal strontium: strontium-90. Produced by fission in an atomic or hydrogen bomb, strontium-90 is metabolized in a way similar to calcium. It is readily taken up by the body, especially a child’s body, and is deposited in bones, teeth, and mother’s milk. Once it is inside the body, it destroys from within. (Nuclear scientists measured strontium-90 dosages in “sunshine units,” but the cheery name didn’t reassure anybody.) And observers were detecting more and more strontium-90 worldwide.
By the mid-1950s, scientists such as Albert Schweitzer and Linus Pauling were raising the alarm. “Each nuclear bomb test spreads an added burden of radioactive elements over every part of the world,” read a Pauling-drafted petition from 1957. “Each added amount of radiation causes damage to the health of human beings all over the world and causes damage to the pool of human germ plasm such as to lead to an increase in the number of seriously defective