PORTLAND – More jobs are at stake at military facilities in Maine than in any other state as the Base Realignment and Closure commission begins voting today on which installations nationwide will close and which will survive.

In a worst-case scenario, more than 9,500 jobs could be lost if the commission votes to shut down the Portsmouth Naval Shipyard in Kittery, the Brunswick Naval Air Station and the Defense Finance and Accounting Service center in Limestone.

Connecticut also faces a potential big hit if the commission closes the Navy submarine base at Groton, which has nearly 8,500 jobs.

Sen. Olympia Snowe, R-Maine, said it’s inconceivable from both military and economic perspectives that the commission will shut down all of the Maine facilities.

“In my view, and in the view of many experts, they are indispensable and irreplaceable,” Snowe said. “So it’s really hard to contemplate the worst-case scenario.”

Commissioners were scheduled to begin voting at 8 a.m. today and the votes were to take place over two to three days. The commission will forward its recommendations by Sept. 8 to President Bush, who has until Sept. 23 to accept or reject the list in its entirety.

The fate of the shipyard and the air station were expected to be decided today. A vote on the Limestone center was expected later.

Because the Defense Department recommended that Brunswick be realigned but not closed, it will take seven votes of the nine-member commission to shut down the facility. If that vote fails, the commission will vote on whether to scale back the base, which would take five votes.

If the base shuts down completely, it would result in the loss of more than 4,800 military, civilian and reservist jobs, according to base officials. If the base is scaled back, it would lose 2,400 jobs and its P-3 Orion planes would move to a base in Jacksonville, Fla.

If Portsmouth closes, it would result in 4,510 job losses, according to the Department of Defense. If the DFAS-Limestone closes, 353 jobs would be lost.

The shipyard, which is located on the Maine side of the Piscataqua River that serves as the Maine-New Hampshire boundary, has a civilian payroll of $318.3 million, according to the Seacoast Shipyard Association. About 60 percent of the shipyard’s employees come from Maine, and 40 percent come from New Hampshire.

Sen. Judd Gregg, R-N.H., said supporters have done all they can to persuade the commission that the shipyard should remain open.

“We’ve made what I believe is a very strong, substantive case and as a result I do remain cautiously optimistic,” he said. “But we’re all sitting, waiting with great anticipation for the big event.”

Maine officials have estimated losses of 12,000 direct and indirect jobs and $465 million a year in payroll in Maine alone if Portsmouth closed and Brunswick were downsized. The numbers would be even greater if Brunswick were closed.

Snowe said that today will be a day of “anxiety and prayer.” She can’t remember any time when so many jobs were hanging in the balance.

“It would take my breath away” if the commission shut down all the facilities, she said. “That would be of seismic proportions, no question, for Maine and America.”