Expected budget cuts have spurred Los Alamos National Laboratory officials to unveil a plan to reduce the lab's work force by 500 to 750 employees.

The lab is asking employees to voluntarily leave, but if not enough do, lab officials plan to lay off workers, lab spokesman Kevin Roark said.

When the layoffs might take place isn't immediately known, Roark said. "All of it is driven by federal approval," he said.

Roark stressed the numbers are estimates, and the federal government hasn't approved the plan yet. Bernie Pleau, spokesman for the National Nuclear Security Administration, said officials at the administration's headquarters must approve the plan, and the timing of the layoffs depends on when that happens.

Lab director Michael Anastasio met for nearly two hours Monday with lab employees and said the layoffs are being brought on by likely budget cuts, Roark said. Anastasio has previously told workers the budget could be flat at best or provide $350 million in cuts at worst. More than 12,100 people work at the lab.

Employees who leave will receive a lump sum based on how many years of service they have put in at the lab, Roark said. The package would be worth up to 39 weeks of compensation, he said.

Some employees who have key jobs are not eligible to take the offer, Anastasio said in a memo to employees, and the lab will notify those employees.

If the lab must lay off employees involuntarily, the lab plans to keep the program available if it is needed, Anastasio wrote. "Future budgets may require additional workforce reductions," he wrote.

U.S. Sen. Pete Domenici, R-N.M., said during his weekly radio address Monday that a congressional resolution is allowing the lab to work at last year's spending levels until Dec. 14. A previous resolution ran through Nov. 16.

"It should come as no surprise that the budget outlook for the NNSA and the lab is very grim as a result of the House-passed budget ... bill," Domenici said.

The U.S. House of Representatives' bill for fiscal year 2008 would put the reliability of the nation's stockpile of nuclear weapons at risk by cutting critical programs, Domenici said.

The House bill would eliminate money for the Los Alamos Neutron Science Center, which is a proton accelerator; Dual-Axis Radiographic Hydrotest, which is a nuclear materials test center; and the Roadrunner supercomputer, Domenici said.

It would also eliminate funding for the Z Machine at Sandia National Laboratories, Domenici said. That machine is the largest X-ray generator in the world.

Domenici said now was a good time to announce possible layoff numbers. "It's bad, but it's not going to get better. We can't have all of our people sitting around waiting, worrying every day of the week. Decisions are going to have to be made, and changes are going to have to be forthcoming. And we'll have to move on to the next step," Domenici said.

U.S. Sen. Jeff Bingaman, D-N.M., said in a statement that he was disappointed the lab's financial situation required the potential cuts. The lab "is one of the finest institutions of its kind in the world, and LANL employees perform a tremendous service to our nation," Bingaman said.

Bingaman said he plans to work with Senate leaders and New Mexico's congressional delegation to get the most money possible for LANL and Sandia.

Gov. Bill Richardson said he urges President Bush and Congress to pass an appropriations bill that would allow LANL and Sandia to continue their vital scientific work. "Congress shouldn't be curtailing their mission, but rather challenging them to continue scientific innovation and help build America's renewable energy future," Richardson said in a statement.

In addition, Richardson said he planned to ask officials from the state Economic Development Department and the Workforce Solutions Department to meet with lab officials and help keep lab workers building the state's economy and making a contribution.

Charles Mansfield, president of the Laboratory Retiree Group Inc., said the layoffs could have an impact throughout Northern New Mexico. "It's not just Los Alamos," said Mansfield, who worked at the lab for 17 years before retiring in 1993. "I think it will hit the whole Española Valley, everywhere from Española up through Taos and El Rito. The lab is a major economic engine for Northern New Mexico."

Mansfield described lab workers as "unique," saying any who are displaced by the layoffs would have to travel to Albuquerque for the nearest high-tech jobs.

Greg Mello, executive director of the Los Alamos Study Group, an Albuquerque-based watchdog group, added: "You have to worry about the vulnerable here in New Mexico. We won't have to worry about scientists that have marketable skills. You have to worry about those who don't ... the technicians and construction workers."

Mello contended layoffs wouldn't be necessary if the lab offered appropriate retirement incentives and reformed what he called "wasteful management practices," including canceling unnecessary construction, reducing subcontractors and cutting back management overhead.

"We need to pull money out of nuclear weapons, which are an obsolete form of security, and put that money into relevant forms of security that are needed in our communities, especially energy security," he said. "If we cling to the labs against the current of history, then were going to be left behind."

Los Alamos is not the only national lab preparing to trim its work force.

Lawrence Livermore National Laboratory in California announced last week that it plans to cut about 500 jobs because of rising costs stemming from a changeover in management and potential federal budget cuts.

Sandia National Laboratories in Albuquerque released its work-force restructuring plan last month, which did not discuss numbers for possible layoffs at Sandia or its satellite location. Sandia spokesman Michael Padilla said Monday that the lab has made no decisions regarding layoffs.

Meanwhile, lawmakers are trying to reach agreement on an appropriations package that would fund the federal government for the remainder of the 2008 fiscal year.

In October, the NNSA released a plan that included general information about what might happen if layoffs occurred at LANL. In the event of layoffs, employees could expect help finding other jobs at the lab and with retraining assistance, the 17-page plan said. It also called for medical benefits and help finding jobs outside the lab.

The plan did not speculate about how many people might be laid off, but was a general plan required whenever layoffs might occur at a Department of Energy defense nuclear facility.

The plan's purpose was to minimize involuntary layoffs, reduce problems for employees who lose their jobs and minimize the effects of layoffs on surrounding communities.

The Associated Press contributed to this report.

Contact Wendy Brown at 986-3072 or wbrown@sfnewmexican.com.