Hoping to close a huge budget gap, Los Angeles Unified School District leaders on Thursday considered slashing about $420 million from next year's spending by eliminating more than 500 nonteaching jobs, cutting employee hours and refinancing debt.

"There's no firing of teachers in this budget. There's no increase in class size," LAUSD Superintendent Roy Romer told the school board. "We need all the teachers we now have."

Most of the jobs would be lost at the district and local district level, not at schools, he said.

L.A. Unified officials kicked off a five-day session of budget talks that is expected to yield a final cost-savings package by next Thursday.

Among the positions proposed to be cut are environmental health specialists, school and early education nurses, and special-education speech and language specialists.

The district has a $540 million shortfall to cover. It hopes some of the remaining $120 million could come from additional state funding. But the district will not know whether it will have that money until the state finalizes its budget this summer.

Even if all the money comes, the district still could face a $60 million deficit. It will consider ways of cutting that between now and Thursday.

"There's a good possibility it's going to be worse than we think it is," board trustee Marlene Canter said. "My suggestion is that we prepare ourselves for the worst case."

Trustees have to decide by next week so they can notify employees who might be laid off by the March 15 state Education Code deadline. Some of the positions will be eliminated through attrition, but many employees will be laid off.

Jobs cuts and related expenses should save about $69 million. In addition, the district hopes to save $144 million from refinancing debt and finding alternative funding for capital projects; $72 million from shifting general fund costs to other funding sources; $61 million from reducing employees' work hours and $71 million from school-site savings.

The 740,000-student district, the nation's second largest, has already cut more than $1 billion, including 2,000 jobs, from its budget in the past three years.