Officials at Los Alamos National Laboratory are having a hard time finding the stuff that somehow didn't make it to the whosiewhatsis inside TA-55, the lab's main plutonium facility.

That's the general gist of a vague news release sent out from the lab Thursday claiming that LANL reported an "internal material control issue" to the National Nuclear Security Administration.

The release says there was an error in "internal inventory and accounting that documents movement of sensitive materials" in a small part of TA-55.

Kevin Roark, a spokesman, declined to say what, exactly, was misplaced according to the accounting. He added that while TA-55 is a plutonium research, development and processing facility, it also "works with a wide variety of nuclear and other materials."

Pete Stockton, however, a senior investigator for the Project on Government Oversight, said he has a pretty good idea about what's missing, and how much of it lab staff are looking for.

"It's plutonium, that's certainly our understanding," Stockton said. "It's an issue of about a kilogram, with is about 2.2 pounds. You'd need about twice that much for a weapon."

While the lab's release said staff noticed the problem in January, Stockton said that problems with "material control and accountability," which is the general category the error falls into, have been going on at the lab and across the complex for more than a year.

Officials from the Project on Government Oversight met with NNSA staff Wednesday to talk about the issue at the lab, but were told that the problem was "classified," according to a news release from the group.

"They say they can't tell you anything, then the lab issues a press release," Stockton told The New Mexican on Thursday. "They're really antsy about this."

The Project on Government Oversight also cited an internal Department of Energy letter that said the amount of nuclear material the lab couldn't account for "exceeded alarm limits."

Roark said there's no way the material left the TA-55 facility. It appears to be a problem of moving material from one area to another, he added.

"That's the most logical explanation — that material is in a place we haven't looked for it yet," Roark said.

He also said security at the facility is extremely tight, with multiple safeguards in place to protect anything from getting out.

"We know nothing's missing because nothing has left the building," Roark said.

That comment, with its circular logic, gave Stockton pause.

"They say there's no way that material could possibly get out," Stockton said. "That's bull."

Stockton pointed to a recent security test at Lawrence Livermore National Laboratory, in which material was taken out of a building and tossed over a security fence with a lacrosse stick, he said.

"You just stash that and take it out the emergency doors," Stockton said.

Still, Roark agreed with the lab's release, which said "there is 100 percent certainty that no sensitive materials left the facility."

And either way, the problem should be resolved soon, he added.

"We expect to have this resolved in the next couple of weeks," Roark said.

Contact Sue Vorenberg at svorenberg@sfnewmexican.com.