SACRAMENTO (CBS/AP) – California Gov. Jerry Brown said Monday he doesn’t know if the San Francisco-Oakland Bay Bridge will open over Labor Day weekend because of safety concerns.

It’s the first time the governor acknowledged serious worries about the structural integrity of the $6.4 billion project to build a new eastern span of the bridge.

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Brown spoke to reporters Monday before delivering a graduation speech for University of California, Berkeley political science students.

“I drive across that bridge, too,” Brown said.

He said the administration is reviewing construction documents going back as far as the administration of former Gov. Gray Davis.

The Federal Highway Administration said last week that it had launched a probe into why seemingly undesirable bolts were used on portions of the new eastern span. Bridge officials have said they have a fix for the cracked bolts that will cost between $5 Million and $10 million.

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On Sunday it was revealed that thousands of steel tendons used to strengthen the skyway portion of the bridge were exposed during construction to rainfall and salty bay mist, leading to corrosion concerns.

A significant question, raised by the Sacramento Bee, was not so much the extent of the problem, but whether Caltrans had enough information about the issue so that outside consultants could make an educated guess or even a reasonable assumption about any possible compromises in safety as a result of the corrosion.

The bridge project is already over budget, but Caltrans was banking on a flawless unveiling of the span to compensate. This most recent issue about possible corrosion, coupled with earlier problems with bad bolts, threatens to derail public support and enthusiasm for the costly project.

The new bridge is replacing a span damaged during the 1989 Loma Prieta earthquake. It’s already years late and billions of dollars over budget.

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