The District has told about 660 teachers and other school employees that their jobs will be eliminated next month because of budget cuts and enrollment shifts but that they will be eligible for other spots in the system, a process that union leaders call tantamount to layoffs.

D.C. officials call it “excessing,” a routine annual redistribution of jobs slots in which schools with budget, enrollment or program changes often shed jobs while others gain them. This year, those being “excessed” may find it tougher to land another position.

Under the old collective bargaining agreement between the District and the Washington Teachers’ Union, excessing was handled on a seniority basis, and teachers cut loose were guaranteed other spots.

But the contract negotiated last year under former chancellor Michelle A. Rhee makes excessing “performance-based,” employing criteria including an educator’s most recent evaluation, “unique skills and qualifications” and “contributions to the local education community.” Seniority still counts, but not for nearly as much.

Moreover, placement of excessed teachers requires “mutual consent,” meaning that school principals aren’t required to pick them up and can elect to hire newly recruited teachers instead. Teachers in good standing who cannot find a position have the option of accepting a $25,000 buyout, early retirement (with 20 years or more of service), or a year at full salary and benefits to keep looking for a spot in the school system.

Nathan Saunders, president of the union, said Monday that under the new contract, excessing is just a way to purge the school system of older teachers. “Excessing is the new teacher firing,” he said. “It’s a lot more palatable, politically correct term.”

School system spokeswoman Safiya Simmons said a series of “transfer fairs” held by the District will help teachers find slots.

The excessing notices have been expected for months. Rising teacher salaries and squeezed school budgets made the action a virtual certainty.

School officials did not provide a breakdown of job shifts by school. But teachers at Duke Ellington and Phelps high schools and the Transition Academy@ Shadd all reported receiving notices. One teacher at Johnson Middle School said the entire staff had been excessed because the school will be reconstituted under the No Child Left Behind law.

“I’m very concerned,” said Saunders, who said he is to meet with Acting Chancellor Kaya Henderson on Tuesday. He also said he doesn’t buy the budget as reason for the excessing, especially since the schools are recruiting prospective teachers.