The West Contra Costa school district will ask voters in September to approve the fourth -- and largest -- school construction bond issue in five years.

If approved, the $450 million bond issue would bring the district's school construction and modernization program to nearly $1 billion.

In a 4-1 vote late Wednesday night, school trustees agreed to hold a Sept. 16 special election. The vote followed no staff report on the merits of the measure and little discussion among board members.

Trustee Karen Leong Fenton cast the sole dissenting vote, but said she would support the bond issue campaign. "I just feel that we should be focusing on the other part of our need, which is academic," she said.

Proponents of the bond measure said more money is needed to bring 49 of the district's campuses into line with facility standards that the school board approved last year.

Those standards closely match the level of construction at Richmond's $36 million Lovonya DeJean Middle School.

"The community has supported (three facilities bonds) and it's clear we haven't addressed all of the needs at all of the schools," said trustee George Harris III. "We think there's support out there. We think we can pass it."

Voters approved Measure E in 1998. The $40.9 million bond issue helped fund DeJean Middle School. In 2000, voters backed the $150 million Measure M. And in 2002, voters approved the $300 million Measure D.

Those funds, touted as major steps to fixing the district's dilapidated and ill-maintained elementary and secondary school campuses, are running out.

Measure M, which targeted the district's 37 elementary schools, will fund construction at just 17 campuses.

It is not clear how far Measure D will go. District officials suspect the bond issue will pay for construction at just five of 12 targeted schools, Harris said.

A community poll, paid for with private funds and commissioned by For the Children of West County political action committee, showed strong support for a fourth bond measure, said school trustee Charles Ramsey.

Poll results were not made public.

"We're not reckless," Ramsey said. "We wouldn't do it" if the support wasn't there.

But Pinole parent Tammy Campbell isn't so sure.

"I think this is the worst thing they could do right now," Campbell said. "They need to drop the bond and do the parcel tax."

The bond campaign does not eliminate the need for a parcel tax to raise needed cash for ongoing school expenses, school trustees said. Such a measure could go to voters in November or March.

If approved by voters, the $450 million facilities bond issue would cost property owners an average of $57.85 per $100,000 of assessed value.

When added to prior school construction bond issues, including Measures E, M and D, the total average annual cost per $100,000 of assessed property value would be $145.63.

The bond measure requires two-thirds voter approval. Bond ballot language calls for a citizen's oversight committee and annual audits.

Aquacena Lopez, a financial adviser to the district, said the state Board of Education agreed to raise the district's debt limit by 0.5 percent to allow the sale of an additional $450 million in bonds.