Four Los Alamos National Laboratory workers were fired and one will resign under pressure for their roles in a security and safety scandal at the lab, the lab's director said Wednesday.

The fired workers were among 23 suspended this summer after two computer disks containing classified information vanished and an intern was injured in a laser accident. The discovery of the missing disks July 7 prompted a virtual shutdown of the nuclear lab, idling about 12,000 workers.

A lab official originally said five workers were fired, but a spokesman later clarified that by saying that four employees were terminated and one "will resign in lieu of termination."

Of the remaining 18 employees, seven were subject to other disciplinary action such as demotion from management, and one remains on investigatory leave. Ten will return to their positions with a finding of "no wrongdoing."

"It's very important to get this behind us," the lab's director, Pete Nanos, said in an interview with the Associated Press via cell phone from an airplane after meetings in the District.

Three of the workers were fired in connection with the missing computer disks; the other two were involved in the laser accident, he said.

Nanos also said the northern New Mexico lab has finished its investigation into the missing disks.