While teams at Los Alamos National Laboratory (search) searched for two missing disks, the Energy Department halted classified research at facilities around the country that use disks like those missing from the New Mexico lab.

The mandate came down Friday from Energy Secretary Spencer Abraham (search), who said it was necessary to get better control over the disks.

Suspension of operations, which officially takes effect Monday, will be lifted once the inventory of the disks is completed and new controls are established. Employees using the disks will also undergo security training.

Classified work was stopped July 15 at Los Alamos after the disks, known as controlled removable electronic media, or CREM (search), went missing about a week earlier. That shutdown was broadened to all Los Alamos operations July 16. On Thursday, 19 Los Alamos employees were suspended pending an investigation into security and safety lapses.

Abraham described the halt at other facilities as precautionary and said he had no evidence that problems at Los Alamos occurred elsewhere.

"We have a responsibility to take all necessary action to prevent such problems from occurring at all," he said, noting that he wanted to "minimize the risk of human error or malfeasance."

Agency officials declined to list the facilities affected, but said the number would range between 15 and 24. The department runs 59 facilities around the country. Among those affected are in California, Tennessee, Idaho, Missouri, New York, Nevada, New Mexico, Texas and Illinois.

"It's obviously unprecedented and suggests that the situation is even more severe than has been realized," said Steven Aftergood, head of the Project on Government Secrecy for the Federation of American Scientists.

The moratorium could prevent DOE from shifting tasks from Los Alamos to other labs, as had been threatened, Aftergood said.

"I think it also reflects a change of heart by Secretary Abraham, who said in May that removable media would be phased out over a period of five years," Aftergood said, suggesting that Abraham now apparently feels it has to be done quicker.

Aftergood said scientific work obviously will go slower, delaying goals that national labs set for themselves every year.

"They have milestones to meet," he said, "and this will set them back."

Danielle Brian, executive director of the Project On Government Oversight in Washington, praised Abraham's decision. The group wants nuclear weapons labs to use "media-less" computers, arguing an insider could download classified information onto removable disks and walk out with them.

"We always believed poor cyber security was a systemwide problem," Brian said.

Aftergood agreed: "The Los Alamos problem is no longer limited to Los Alamos -- it's a systemic problem."

While Los Alamos teams are searching more than 2,000 safes and vaults for the missing disks, the Nevada Test Site has already accounted for its classified material. Administrators there were checking whether its nuclear stockpile stewardship programs will shut down, said Darwin Morgan of the National Nuclear Security Administration in Nevada.

The Pacific Northwest National Laboratory in Richland, Wash., is not a weapons lab but had already began an inventory of computer disks related to classified work.

"PNNL is always looking for ways to better handle classified material, so we welcome this," said spokesman Geoff Harvey.

The Pantex plant near Amarillo, Texas, the nation's only nuclear weapons dismantling plant, will shut down, Pantex spokesman Jud Simmons said.

Spokesmen also confirmed the order affects the Y-12 nuclear weapons plant and parts of Oak Ridge National Laboratory in Tennessee; NNSA's site office in Kansas City, Mo.; Argonne National Laboratory outside Chicago; Lawrence Livermore National Laboratory in California; and Sandia National Laboratories in Albuquerque.

Lawrence Livermore spokesman David Schwoegler said the order affects 876 of 9,000 workers at the lab, which has accounted for all removable disks -- about 12,000 -- in three straight annual inventories. Two-thirds are centrally stored.