Duck and Cover, became an icon of the Cold War, seen by many as evidence of the absurdity of the government's response to the nuclear threat. Against the threat of a nuclear attack, how much good would diving under a desk really do? Originally aimed at teaching children how to respond to a surprise nuclear strike, by the 1980s Duck and Cover was a piece of 1950s kitsch, mocked in such anti-nuclear films as The Atomic Cafe. Sixty years ago, in 1951, Ray Maurer and Anthony Rizzo produced a film for the federal government's Civil Defense agency in response to Soviet nuclear tests. Featuring an animated turtle named Bert and real-life schoolchildren from New York, the film,became an icon of the Cold War, seen by many as evidence of the absurdity of the government's response to the nuclear threat. Against the threat of a nuclear attack, how much good would diving under a desk really do? Originally aimed at teaching children how to respond to a surprise nuclear strike, by the 1980swas a piece of 1950s kitsch, mocked in such anti-nuclear films as





But now "duck and cover" is back, not as kitsch but once again as serious advice from the federal government. Faced with growing concerns about a nuclear attack on one or more major cities -- this time from terrorists, or bombs smuggled instead of dropped by countries like Iran or North Korea -- authorities are once again looking to educate citizens about what to do in the event of a nuclear attack. And that advice sounds a lot like what they were saying in my grandfather's day: Duck and cover.





As outlined in a lengthy planning document developed by a federal interagency committee led by the Executive Office of the President and released last summer, national and especially local authorities should be making plans to educate people to take cover and shelter in place after a nuclear detonation.



This has inspired a certain amount of snark from the Obama Administration's critics

So was the advice crazy back then, and is it crazy now? The answers are "probably not," and "no." The snark, though understandable, is misplaced.

Even short-term sheltering (a day or two) before attempting to evacuate the area will dramatically increase the number of survivors. The difficulty, as the planning document puts it, will be overcoming people's "natural instincts to run from danger and reunify with family members." Overcoming those instincts will require preparation and education on the part of public health and school authorities.

Dr. Strangelove, a war involving thousands of megaton-yield hydrogen bombs. (A megaton is the equivalent of a million tons of TNT, or about 60-70 times the power of the Hiroshima atomic bomb, which had an explosive power of around When Americans think about nuclear war, we tend to think about the apocalyptic scene at the end ofa war involving thousands of megaton-yield hydrogen bombs. (A megaton is the equivalent of a million tons of TNT, or about 60-70 times the power of the Hiroshima atomic bomb, which had an explosive power of around 15 kilotons , the equivalent of 15,000 tons of TNT). But in 1951, neither the United States nor the Soviet Union had yet tested a hydrogen bomb, and the duck-and-cover era authorities were basically preparing people for a rerun of Hiroshima and Nagasaki with us on the receiving end of relatively small numbers of (relatively) small nuclear weapons. "Duck and cover" advice is particularly effective there.





An atomic explosion can blind you, burn you, crush you with explosive power, or poison you with radiation. The "duck and cover" advice, based in no small part on the experience of Hiroshima and Nagasaki survivors, was designed to do what could be done to minimize that.





When an atomic bomb explodes, several things happen in short order. First is a flood of "prompt" radiation created by the nuclear fission that produces the explosion. The good news -- if you can call it that -- is that if you are close enough to get a lethal dose of prompt radiation, you're close enough that you're likely to be killed by other bomb effects before it becomes an issue. Next comes the "flash," a brilliant pulse of light created as the air around the bomb is heated to millions of degrees; this starts out as ultraviolet, falls quickly into the visible light range, and then into the heat-ray infrared range within a few seconds. The flash can blind, or burn exposed skin, and start fires. Next comes the blast, as the superheated air expands outward, initially at supersonic speeds. The blast is dangerous on its own, and also because it crushes buildings and creates clouds of flying glass and debris.





Given that light travels almost instantaneously, for everyone outside the immediate vicinity of the bomb the flash will arrive before the blast. Furthermore, the fire-setting infrared part of the flash peaks a few seconds later than the initial burst of light. So those who see a brilliant flash of light -- and know what it means -- have a few seconds to get under some sort of cover to protect themselves from what comes next.





After these "prompt effects" of initial radiation, flash, and blast have passed, there is an additional hazard. A nuclear explosion sucks air, dust -- and, if it's close to the ground, vaporized soil, buildings, etc. -- up into the fireball, where some components are transformed into radioactive isotopes that then fall out of the cloud and back to earth over the next few hours, hence the term "fallout." The radiation from fallout can be severe -- the bigger the bomb, and the closer it is the the ground, the worse the fallout, generally -- but it decays according to a straightforward rule, called the 7/10 rule: Seven hours after the explosion, the radiation is 1/10 the original level; seven times that interval (49 hours, or two days) it is 1/10 of that, or 1/100 the original, and seven times that interval (roughly two weeks) it is 1/1000 the original intensity. Because it is dust, fallout travels with the wind.





A terrorist bomb is likely to be relatively small -- possibly only a fraction of the Hiroshima bomb's explosive power -- and likely exploded at ground level. This means that the area totally destroyed by the explosion is likely to be much smaller than the area exposed to lesser damage or to fallout radiation ( this nuclear weapons effects calculator from the Federation of Atomic Scientists will let you see the effect of different sized bombs burst at different heights). Because of this, Homeland Security people in the Obama Administration have been encouraging a duck-and-cover approach, followed by advice to "shelter in place" against fallout rather than trying to evacuate the area.





A terrorist atomic bomb might be small by Dr. Strangelove standards, but by any other standard its effects would be catastrophic. An area composed of dozens of city blocks would be essentially destroyed; a larger area surrounding it would be heavily damaged and filled with injured people; and an even larger area surrounding that one would be somewhat damaged, with roads blocked, powerlines down, and widespread confusion.





Those few survivors -- mostly badly injured, unless they happened to be inside a bank vault at the time, or something -- in the central area are likely pretty much on their own. The chance that emergency services can get into the zone and find them before the fallout starts to settle is virtually zero. Those in the middle zone may get some help, but not right away. Those in the outer zone, however, will be tempted to flee, and that's what the authorities want to discourage.





The radiation from fallout is blocked by pretty much anything that has mass. (Here's the government's Citizen Corps guide ). If you're in the basement of a typical home, you can expect to receive less than a tenth the radiation you'd receive outdoors. If you're in an interior room halfway up a tall building (fallout is dust, and settles on the ground, or on roofs), or in an underground parking garage, you may receive less than a hundredth the radiation. And you can further reduce the dosage by piling up anything heavy (books, furniture, etc.) overhead and by sealing windows and doors with duct tape and plastic to help keep the radioactive dust out. (The government used to publish pamphlets on how to improvise a fallout shelter in your basement; those will probably come back.)





In the face of a Strangelovian apocalypse, this degree of protection might only have produced a slower death, but for those facing a terrorist bomb such protection is likely to be adequate, and much safer than, say, being stuck in traffic on the Beltway when the fallout begins to settle. Also, people sheltering in place won't tie up roads, making it easier for emergency services to get where they're needed. So the Obama Administration wants to encourage people to shelter in place rather than head for the hills in the event of a nuclear attack. Even sheltering for a few hours, or a couple of days, lets radiation levels fall dramatically and avoids road tie-ups for later evacuation.





But will people follow that advice? To follow it, they've first got to hear it, and usual sources of information like radio, TV, and the Internet may not be working. (Not only will power likely go out -- because of those downed powerlines -- but one of the other prompt effects of a nuclear explosion is something called Electro-Magnetic Pulse. A nuclear burst at the edge of the atmosphere could fry electronics over hundreds of miles; a ground-level one does less damage, but makes reliance on electronics near the blast site iffy.). So if you want people to know what to do, you have to tell them in advance.





New York Times noted, the question of how to educate people without panicking them, or creating political backlash, has generated considerable discussion within the Obama Administration. (One message, using an attack on Las Vegas as an example, was torpedoed by Senate Majority Leader Harry Reid, of Nevada, who thought it bad publicity for a town already hit hard by the recession.) But telling them in advance has its own risks. To some, duck-and-cover may be amusing kitsch, but when I showed the film to my teenage daughter while researching this piece, she found it terrifying. (Welcome to my Cold War childhood). And, as a recent article noted, the question of how to educate people without panicking them, or creating political backlash, has generated considerable discussion within the Obama Administration. (One message, using an attack on Las Vegas as an example, was torpedoed by Senate Majority Leader Harry Reid, of Nevada, who thought it bad publicity for a town already hit hard by the recession.)





It has also generated some criticism from those who remember how much flak Bush Homeland Security czar Tom Ridge got for similar proposals -- right down to the duct tape and plastic sheeting -- when the Department of Homeland Security was new. It's understandable that people might snark about that, but physics is no respecter of political differences. That the Obama Administration is pursuing a policy driven by science, rather than by politics, is something that should be praised, not criticized.





Of course, one question not driven -- directly, anyway -- by science is the question of how likely a nuclear attack might be. On that subject, the Obama Administration, presumably, has better intelligence than I do. But I note that the feds seem to be highly interested in an experimental new drug for treating radiation sickness. That's not encouraging.





If the likelihood of a nuclear attack is hard to judge, what's beyond dispute is that we are in many ways much less prepared to deal with one than we used to be. Fallout shelters in public buildings are no longer marked and stocked, and public knowledge about nuclear weapons and their effects isn't what it was during the Cold War era. In the course of teaching nuclear-related cases in my Administrative Law and National Security Law courses, I've observed that most of my students (military veterans and a few emergency-services types excepted) know next to nothing about A-bomb related things that were common knowledge a couple of decades ago. Replenishing that popular knowledge base seems worthwhile, as long as there are nuclear weapons on the planet.





There's something else worthy of praise in the Obama Administration's approach, something that goes well beyond the terrorist-nukes field. The Times article mentioned above includes this quote from Brian Kamoie of the National Security Council: "We're working hard to involve individuals in the effort so they become part of the team in terms of emergency management."





The feds' estimate is that it will be at least a couple of days before significant outside aid arrives at the scene of a terrorist nuclear attack. But as experience from disasters like Katrina demonstrates, outside aid always takes longer to arrive than you expect. A philosophy of empowering individuals, and encouraging preparedness on the part of ordinary citizens, will pay dividends in the event of all sorts of disasters, whether natural or "man-caused."





Encouraging people to take even modest steps to prepare themselves in advance will undoubtedly save lives, even if the terrorist attack never comes and Washington is, instead, struck by an asteroid, an earthquake, or a hurricane. As we head into a 21st century that appears to be a lot less secure than 1990s prognostications suggested, it's probably best to prepare for the worst.

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