The District public school system has about 640 more employees than its budget allows, the result of a chronic failure to control personnel spending, school officials said yesterday.

Projections show that the school system will exceed its personnel budget by about $31.5 million this fiscal year unless cuts are made, and it also will face a shortfall of about $33.3 million in non-personnel areas because of recent trims the city made in school funding and other factors. School board members said that they would have to make deep spending cuts to avoid a deficit in the $922 million budget but that they had not yet determined what to eliminate.

School officials said the personnel cost overruns resulted from excessive hiring and the miscalculation of employee salaries and benefits. They acknowledged that many employees were hired without anyone checking to see whether their jobs were covered in the budget. According to the figures provided yesterday, the school system's budget calls for 10,691 employees, but there are about 11,330 on the payroll.

During a D.C. Council hearing yesterday, council members expressed outrage that too many people had been hired.

"We're paying 600 people who are not supposed to be paid," said Adrian M. Fenty (D-Ward 4). "I am staggered by some of the numbers here. . . . I have to find out how mistakes of this proportion . . . have been allowed to reach this point."

In an interview yesterday, Superintendent Paul L. Vance blamed financial systems that have failed for years.

"It's just an accumulation of past ills," Vance said. "This is part of the system's financial conditions that have to be cleaned up."

For many years, the school system had been unable even to say how many employees it had. Officials heralded their recently completed tally as evidence of improvement in that area.

School administrators asked for an employee count in September 2001, when the school system was facing a budget deficit estimated at $60 million.

They said it took 18 months for the city's chief financial officer and school human resources officials to produce a list showing how many employees were on the school payroll and which positions were budgeted.

The school system also overspent on personnel in the fiscal year that ended in September and had to freeze other spending as a result.

The report officials released yesterday showed that certain departments within the school system are responsible for much of the over-hiring.

For instance, the transportation department, which buses some special education students, was supposed to have 787 positions but instead employed the equivalent of about 1,079 full-time workers. One reason, school officials said, is that people were hired to compensate for a high rate of absenteeism among drivers.

The school system's early childhood programs were supposed to employ 104 but instead employed the equivalent of about 199 people. School officials yesterday could not explain how that occurred.

Louis J. Erste, the system's chief operating officer, said he was trying to determine how too many people were hired in various departments. He said officials have been concentrating on budget cuts and have not yet focused on who is to blame.

In the case of 71 school employees, the system's personnel department has not determined what jobs they are performing, and officials could not rule out the possibility that some of them are being paid but not reporting to work.

The school system had not previously prevented department heads from hiring too many employees but now has such a system in place, said Robert A. Morales, who took over as the schools' chief financial officer in April 2002.

"There was no position control," Morales said. "A grant could disappear, but nothing said, 'Take this position out.' "

In addition, Morales said that when individual schools crafted their budgets, they did so with flawed information.

For instance, average teacher salary numbers provided by the chief financial officer to the schools were low, leading to budgets that did not conform to actual costs, Morales said. He said some schools employed the correct number of people but are still spending beyond their budgets.

School board members said they have held closed-door meetings with Vance in recent days in which he has laid out options for avoiding a deficit, including freezing spending by individual schools and other steps that they and Vance would not discuss.

Board of Education President Peggy Cooper Cafritz (At Large) told the council that employees would have to be fired but that it was too early to say which ones.

"Clearly, people are going to have to be taken off the rolls, and they will be," Cafritz said.

School board member Tommy Wells (District 3) said the over-hiring and overspending cannot all be blamed on problems from years ago.

"We have to be sure that our managers are held accountable," Wells said. "This happened on our watch. . . . We'll have to take a serious look at the decisions that were made that caused this."