California voters were evenly split Tuesday over whether to approve the second major injection of cash into the state's aging and overcrowded schools in less than two years.

Proposition 55, a $12.3 billion school facilities bond measure, took a slight lead early this morning with nearly three-fourths of precincts reporting.

East Bay schools are counting on as much as $771 million from the state bond measure for projects such as the replacement of seismically unsafe El Cerrito High School, air conditioning in the Mt. Diablo school district and three new schools in Brentwood, the fastest-growing district in the state.

Some supporters attributed the close results to voters' reluctance to approve both multibillion-dollar bond measures on Tuesday's ballot.

Proposition 57, Gov. Arnold Schwarzenegger's $15 billion economic recovery bond, may have hurt the school bond's chances, they said.

"The way it plays out in the state is the $15 billion is going to solve everything, and the $13 billion is not needed," said Ariel Owen, a sixth-grade science teacher at Foothill Middle School in Walnut Creek who campaigned for the school bonds.

But Owen wishes voters could see the poor condition of many schools. Gallons of water fell through her classroom roof during the last hard rain, she said.

Mike Arata, a board member of the Alliance of Contra Costa Taxpayers who opposed the school bonds, said he expected Prop. 55 to pass, although the two big state bond measures could have worked against each other.

"I don't think enough people pay attention to the core fact that bonds equal taxes," he said.

Many East Bay districts have passed local bond measures in the past few years and qualify for state matching money for their projects. But the $13.05 billion from state bonds approved by voters in 2002 to provide those matching funds has nearly run out.

The West Contra Costa school district, for instance, qualifies for about $55 million from the state to supplement $450 million in local bonds.

West Contra Costa schools have been greatly neglected over the years, and patchwork repairs are no longer enough, said Terri Jackson, president of the United Teachers of Richmond. Jackson appeared in TV commercials urging voters to approve the proposition.

If the state bonds failed, the district would have to scale back the projects, she said.

"Any more money, whether it's local or state, that can come in and fix these schools, the better," she said. "With the exception of the new ones, they all need repair. Bathrooms, heating systems, everything needs desperate help."

In the winter, some West County students and teachers shiver in classrooms because the main heating systems do not work. Space heaters cannot be used because they blow the aging circuits, she said.

In the late spring, summer and early fall, schools in the Mt. Diablo district have the opposite problem. Classrooms get unbearably hot, because there is no air conditioning, Owen said.

With a hoped-for $80 million from Prop. 55 to help renovate the district's schools, installing air conditioning would finally be possible.

If the school bonds failed, they automatically will be placed on the ballot in November.

"If it doesn't go through now I don't see why it would go through in November, but I will be at the front trying to get it to do so," Owen said.