OAKLAND  (AP) — Two of San Francisco Bay Area Rapid Transit’s largest unions and management returned to the bargaining table Sunday in an 11th hour attempt to avoid a potential strike.

Representatives from Service Employees International Union Local 1021, Amalgamated Transit Union Local 1555 and BART were scheduled to begin negotiations Sunday afternoon as the unions’ contracts are set to expire at midnight.

The meeting comes nearly 24 hours after union negotiators said they would likely strike, which would cripple the region’s Monday morning commute.

As the deadline nears, both sides say they are far apart on key sticking points including salary, pensions, health care and safety. Anticipated around-the-clock negotiations had fallen apart Saturday as the unions packed up and left after talks stalled.

Sunday’s last-ditch talks also come after Gov. Jerry Brown’s secretary of the Labor and Workforce Development Agency, Marty Morgenstern, requested the parties continue negotiating to prevent a work stoppage of the nation’s fifth-largest rail system.

“Our team is not encouraged by BART’s proposal, but we are going to bargain at the request of the labor secretary in good faith as we have all along,” said Josie Mooney, an SEIU chief negotiator. “But if BART continues to do ‘surface bargaining,’ then we will not come to an agreement.”

Brown spokesman Evan Westrup said Sunday that the governor will not call for a “cooling off period at this time” as state mediators will continue assisting the negotiating parties.

“BART and its labor unions owe the public a swift resolution of their differences,” Westrup said. “All parties should be at the table doing their best to find common ground.”

The unions want a 5 percent raise each year over the next three years. BART said Saturday that train operators and station agents in the unions average about $71,000 in base salary and $11,000 in overtime annually. The workers also pay a flat $92 monthly fee for health insurance.

BART spokesman Rick Rice said BART’s latest proposal offered a total of an 8 percent salary raise over the next four years, instead of its original offer of a total of 4 percent over the same period. The proposed salary increase is on top of a 1 percent raise employees were scheduled to receive Monday, Rice added.

The transit agency also said it offered to reduce the contribution employees would have to make to their pensions, and lower the costs of health care premiums they would have to pay.

“They are not straight across-the-board raises. They haven’t provided us with the information that we need, numbers on the budget are bouncing all over the place, they change almost daily,” ATU Local President Antonette Bryant said Sunday. “We can’t bargain with incorrect or misinformation.”

Rice said Sunday that BART’s latest proposal may not be its best last offer.

“We need to have some substantial discussions,” Rice said. “I hope we can make some progress.”

Mooney, the SEIU’s chief negotiator, said Saturday after talks stalled that there was “a 95 percent chance” that the unions would strike, after claiming that the unions have met with BART’s management for only 10 minutes in the past 36 hours.

The two unions, which represent nearly 2,400 train operators, station agents, mechanics, maintenance workers and professional staff, had no plans to meet with BART on Sunday.

But, with a walkout that could affect every mode of transportation, clogging highways and bridges throughout the Bay Area, the governor’s office request may salvage talks.

BART’s last strike lasted six days in 1997. On Friday, other area transit agencies urged commuters to consider carpooling, taking buses or ferries, working from home and, if they must drive to work, to leave earlier or even later than usual.

A strike would be “an absolute nightmare,” said Jim Wunderman, president and CEO of the Bay Area Council, a business advocacy organization.

“Our transportation system simply does not have the capacity to absorb the more than 400,000 BART riders who will be left at the station,” Wunderman said Saturday. “There will be serious pain.”