Washington

The bulk of classified research at all 24 labs run by the US Department of Energy was shut down this week after officials decided that the security problems recently found at the Los Alamos National Laboratory in New Mexico might also exist elsewhere.

Several computer disks went missing at Los Alamos earlier this month, prompting energy secretary Spencer Abraham to halt all work at the lab until the problems are ironed out (see Nature 430, 387; 2004). As of 26 July, two missing disks had still not been found, and 15 employees had been suspended in connection with the disappearance.

Now all energy labs will stop doing classified research that involves removable storage devices — such as computer disks — until all the devices are accounted for and new procedures are in place for monitoring their handling by laboratory employees.

“While we have no evidence that the problems currently being investigated are present elsewhere, we have a responsibility to take all necessary action to prevent such problems,” Abraham said on 23 July.

The shut-down isn't quite as dramatic as it sounds, experts say. Only two labs will be seriously affected: Sandia National Laboratories in Albuquerque, New Mexico, and Lawrence Livermore National Laboratory in California. Together with Los Alamos, these two labs conduct the bulk of the country's nuclear-weapons programmes. At Livermore, 876 employees will be suspended during the inventory of some 12,000 items of classified removable material.

At other labs, far fewer people will be affected. “The impact should be minimal,” says Martha Krebs, former director of the energy department's science office.