The Metropolitan Transportation Commission voted unanimously Wednesday to turn back the clock by rescinding its earlier approvals to use bridge toll revenues to buy a new building in San Francisco's SOMA neighborhood for a regional government hub.

The vote came during a special meeting called in response to complaints that a closed session July 27 violated state open meeting laws. Oakland City Attorney Barbara Parker said the violation occurred when officials from other government agencies were invited into the closed session to discuss the purchase of a new regional headquarters building at 390 Main St. in San Francisco. Parker said any action taken that day should be nullified.

The 390 Main St. building was to have housed MTC, the Association of Bay Area Governments, or ABAG, the Bay Area Air Quality Management District and commercial tenants. The ABAG board voted against the San Francisco selection last month, and the air district voted for it.

Wednesday's vote was a huge relief to Oakland officials, although it does not mean that San Francisco is out of the running.

At its July 27 meeting, the MTC and the Bay Area Toll Authority authorized the use of $105 million in bridge toll revenues to purchase the San Francisco building -- built in the 1940s as a tank warehouse -- and an additional $74 million to rehab it and get it ready for new tenants. The U.S. Postal Service sold the building last year for $60 million.

The MTC was asked Wednesday to reauthorize that action; however, it opted instead to have a six-member committee composed of former commission chairmen, the current chairwoman and vice chairwoman look into the questions and concerns raised by public officials and others opposed to the agencies' move to San Francisco. The committee will return with its report within 60 days.

Those questions include public transit accessibility issues, the use of toll revenues to buy a building that will be used in part for commercial leases, the absence of engineering estimates to retrofit the building, the number of parking spaces and whether a fair cost comparison had been done for the San Francisco building and a new Oakland development at 1100 Broadway favored by East Bay officials and business leaders.

State Sen. Mark DeSaulnier, D-Concord, also asked for an audit to determine if bridge tolls could be used to buy the building.

"I think the vote was a very positive move for regional planning and transit-oriented development and for fully informed decision making," said Rebecca Kaplan, at-large representative on the Oakland City Council and a member of ABAG's board.

SKS Investments, owners of the 1100 Broadway development, has been saying for weeks that it was instructed to use a more expensive financing option than MTC plans will use to finance the purchase of 390 Main St., although the real estate consultant said Wednesday the request for proposals did not mention any particular type of financing requirements.

MTC Executive Director Steve Heminger defended the choice of 390 Main St. and said he had no question that the San Francisco building was the best candidate. But Oakland's deputy director of planning, Eric Angstadt, cautioned the commissioners that they had not been given "complete information or a complete analysis" of the two sites' costs

There were allegations of bias coming from many angles. Commissioner Scott Haggerty hinted that MTC's consultant, CB Richard Ellis, favored the 390 Main St. purchase because the company would receive a $2 million commission at close of escrow, versus a $2.1 million commission from the developers of 1100 Broadway when the building is completed in two years.

MTC Commissioner Scott Wiener, who represents San Francisco, said he was disappointed by the delay and said Oakland officials had "gone overboard" in their opposition and stirred "up an unnecessary hornet's nest" by bringing so many speakers. He warned that the San Francisco deal could "go south" because of the delay.

"We need to make decisions based on the facts, not on cheerleading," Wiener said, adding that he would go along with a request to study the issues raised by the public.

Vice Chairwoman Amy Worth and Chairwoman Adrienne Tissier said there were too many issues that needed answers before the agency could move ahead with the building purchase.

"We've heard some issues and received some letters that make it important to vet those issues" before making a decision, Tissier said. Whether the board votes for or against 390 Main St., "no one can say we didn't listen to the public and vet these issues."

Follow Cecily Burt at Twitter.com/csburt.