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What's in the Los Alamos Disks?

The temporary disappearance of two computer hard drives, smaller than a paperback spy novel, at the Los Alamos National Laboratory in New Mexico has focused attention on the government's mobile team of nuclear experts whose job is to combat nuclear terrorism. The Department of Energy has confirmed only that the disks stored information that might help its Nuclear Emergency Security Team (NEST) find, identify, and disarm a homemade atom bomb or stolen warhead. But there's been a range of speculation on what that information might mean in the hands of unauthorized users.

The disks went missing 7 May or earlier from a high-security vault, but the lapse wasn't reported until weeks later. They reappeared 16 June behind a copying machine. Investigators are still trying to determine whether the disks were pocketed by spies or mislaid by employees during the excitement of last month's fire that swept through Los Alamos, and they haven't announced whether the disks were even accessed while they were missing.

Those familiar with NEST have speculated that the hard drives contain information, ranging from bomb radiation signatures to wiring diagrams, that could be valuable to terrorists and aspiring nuclear powers. Even poorly detailed guides to the shape and construction of weapons components, says Greg Mello of the nonprofit Los Alamos Project in Santa Fe, "would shave years off new weapons development by helping [data-poor countries] avoid dead-end research alleys."

Although some commentators claim the information could help bomb thieves figure out how to detonate a stolen weapon, other specialists doubt that scenario. Even savvy terrorists probably wouldn't be able to defeat the multiple security devices that prevent an unauthorized user or an accident from detonating a weapon manufactured by one of the major nuclear powers, says arms-control scholar Dan Caldwell of Pepperdine University in Malibu, California. U.S. and European warheads are known to carry "electronic combination locks," says Caldwell. Multiple codes, tamper-proof trigger mechanisms, and sensors protecting detonating explosives would stand in terrorists' way; Mello agrees it "doesn't seem to be the most plausible" scenario that the hard drives could aid terrorists in detonating a bomb.

As Congress debates how to improve security at weapons labs, many Los Alamos researchers are demoralized by the latest publicity and beg to be left alone. "Things were just getting back to normal after the fire," says one scientist. "Now we're right back in the flames."