Cities need to prepare for a home-made nuke

There used to be a time when the nuclear arsenals of the United States and the Soviet Union had about 20,000 nuclear warheads each. The number of warheads has been steadily reduced under various bilateral treaties during the past three decades, and the U.S. and Russian arsenals no contain between 1,600 and 2,200 warheads each (these are strategic warheads; the number of tactical nuclear warheads is a separate issue). Earlier this week, in a meeting in Moscow, the leaders of the two countries were discussing further reduction in the number of warheads to between 1,200 and 1,500, and also reductions in the number of strategic delivery vehicles to between 500 and 1,100.

David Shiga writes that these discussions notwithstanding, a different nuclear threat is preoccupying emergency planners back home. A panel of medical experts has just released its assessment of the technologies and therapies that could be rolled out if a home-made nuclear bomb was ever detonated in the heart of an American city.

A device of this kind — which Obama judges to pose “the most immediate and extreme threat to global security” — would kill hundreds of thousands of people. As catastrophic as such an attack would be, it would not level an entire city, and a timely response could save many lives. Recent advances in techniques for mapping the path of radioactive fallout after an attack, combined with novel therapies for treating radiation victims, will improve survival chances, the report says. “Clearly there would be loss of life, but it’s not hopeless,” says Georges Benjamin, head of the panel of doctors and public health officials that was convened by the National Academy of Sciences to assess the nation’s level of preparedness for such an attack. “We feel that there are things that one can do to mitigate it.”

What would a city need to do? The panel explored the consequences of a nuclear explosion equivalent to 10,000 tons of TNT. This is tiny compared with the thermonuclear weapons deployed by the U.S. and Russia — and smaller even than the 15-kiloton bomb dropped on Hiroshima in 1945 — but plausible for an improvised device. The blast wave would destroy buildings and kill almost everyone within one kilometer, so the panel focused its attention on people outside this zone, for whom the main danger would come from radioactive fallout. “That’s a place where you could get big gains if you plan right,”