Oakland may be on the cusp of losing at least one major employer, possibly two. The Metropolitan Transportation Commission, which shares space in Oakland with the Association of Bay Area Governments, appears poised to approve a plan to move its headquarters to San Francisco. MTC, and possibly ABAG, would share space with the Bay Area Air Quality Management District at the old post office building at 390 Main Street in the city. The air district likely will approve the deal on Monday, although it won’t become final until MTC’s board votes on it later this month.

Oakland had been in the running to host a joint center for the three large public agencies, but now appears to be a long shot, even though the Oakland property under consideration — 1100 Broadway in downtown — is much more centrally located than the apparent winner in San Francisco. The Oakland property, a vacant lot on which a 320,000 square foot office tower would be constructed specifically for the three public agencies, is one block from the 12th Street BART station, and is right on a major AC Transit corridor. By contrast, the San Francisco site is nearly a half-mile from the closest BART station.

Ironically, the air district favors the San Francisco spot, even though the agency is charged with protecting the region’s air quality and getting commuters to take mass transit. Air district employees reportedly prefer to stay in San Francisco because many of them live there — particularly high-ranking officials with the agency — and they don’t want to commute to the East Bay.

Berkeley Mayor Tom Bates, who sits on both the air district and the MTC boards, said MTC also favors the San Francisco site because it’s larger, and would allow the agency to recoup some of its investment by renting out part of the building. He said he would prefer that the joint-agency headquarters be located in Oakland, but said the Oakland site is too small. The three agencies not only need office space, but meeting and conference space, along with rentable offices to make the deal work, he said. “I don’t think there’s any choice,” he said. “There’s no real viable option in Oakland.”

Bates said he would have supported a joint headquarters at the Clorox building in Oakland, but then Clorox decided that it wasn’t interested in selling, even though the company has transferred most of its Oakland workers to Pleasanton. The Clorox building had originally bid to host the public agencies, and was one of the finalists — along with the Main Street site in San Francisco and 1100 Broadway. The other two finalists who have since been ruled out were Market Square in San Francisco and the Sears Building in Oakland.

Bates said he expects the air district board to green light the 390 Main Street proposal on Monday. MTC’s board is slated to take up the proposal on July 27. However, there’s no guarantee that ABAG will go along. Bates said ABAG may choose to remain in Oakland, because most of its employees live in the East Bay. ABAG currently shares space with MTC near the Lake Merritt BART station. Combined, the three agencies employ about 620 people.

Oakland Mayor Jean Quan, however, said she is not giving up the fight to host the agencies’ joint headquarters. She said that the original request for bids didn’t make it clear that MTC’s demand for extra space to rent out would become the deciding factor in the selection process. Oakland is now considering offering the shuttered Henry J. Kaiser Convention Center, along Lake Merritt, she said. Like the Main Street spot in San Francisco, the Kaiser center would require major remodeling, but it’s large enough for MTC to rent out part of the space. Quan also said the city is looking at rezoning the Lake Merritt area in a move that would enhance the value of MTC’s current headquarters and potentially convince the agency not to leave.