The lab will give pink slips Thursday to 330 career employees, and another 110 on Friday.

More than a third of those being laid off are scientists and engineers at the lab, which conducts nuclear weapons research and other national security and scientific work.

Lawrence Livermore is working as hard as possible to place the laid-off workers in new jobs, said lab spokeswoman Susan Houghton. The lab has identified more than 1,000 possible private-sector jobs that the laid-off workers might apply for.

The lab's work force was about 8,000 just two and a half years ago, but has been reduced by some 1,800 through attrition, retirements and layoff.