The Contra Costa Taxpayers Association, after "vigorously" supporting West Contra Costa's three prior bonds, is opposing the school district's latest measure, the $450 million Measure C.

The United Teachers of Richmond has taken an opposite stance. The teacher's union, which represents some 2,000 West Contra Costa educators, voted Wednesday to endorse the measure.

"The teachers are supportive of improving their teaching and learning environment," said UTR President Terri Jackson.

If approved by two-thirds of the voters, Measure C would bring the school district's bond construction program -- already more than $450 million -- to nearly $1 billion.

The money will be used to continue renovating and rebuilding most of the school district's aging campuses.

The election is Tuesday.

Kris Hunt, executive director of the nonprofit Taxpayers Association, said the group rarely opposes school bonds and has done so just once in the last decade.

But the association's board has grown wary of West Contra Costa's mounting debt load and frustrated by the lack of detailed financial information on current bonds, she said.

"I don't know that anybody is denying that they may in fact need the money. The question is how is it being handled," said Hunt.

Kevin Reikes, Measure C's Sacramento-based campaign consultant, said the taxpayer group's opposition is unfair.

"These are the same groups that sponsored Proposition 13 ... and ultimately that's why we have to go to bonds, because taxpayer groups gutted our ability to pay for schools," Reikes said.

"It's like OK, so take away our ability to use property taxes for local public education, and then force a system where to raise money for schools we have to go into bond indebtedness, and then oppose those."

Hunt countered that her organization supported West Contra Costa's bond elections in 1999, 2000 and 2002.

The Taxpayers Association is also concerned about the school board's talk of a parcel tax election in March, which would further tax the district's property owners, Hunt said.