BELFAST, Maine — After nearly two and a half years of contract negotiations, RSU 20 directors and the teacher’s union are no closer to a resolution — and Superintendent Bruce Mailloux said Monday that the protracted dispute is “like a cancer.”

“It eats at your district,” he said. “Morale, attitudes, all of that. It’s in everybody’s best interests to get this done.”

Because the members of the Education Association by the Bay at the end of February voted down a proposed contract settlement, the dispute now will be addressed in arbitration — the last step in a state-mandated contract resolution process.

Betty Lu Brown, president of the 180-member association, said the vote was nearly unanimous not to accept the contract. The sticking point, she said, is that this contract would be the first to unite teachers from the former SAD 56 in Searsport and the former SAD 34 in Belfast, which were brought together under Maine’s school consolidation law. The consolidated district includes the communities of Belfast, Belmont, Frankfort, Morrill, Northport, Searsmont, Searsport, Stockton Springs and Swanville.

Salaries for SAD 34 teachers were generally much higher than the salaries for SAD 56 teachers.

The rejected contract would have placed all teachers from the two former districts on the same salary scale by the 2013-2014 school year, according to a statement from the school board that was issued last week.

The scale would have ranged from $31,310 for a first-year teacher with a bachelor’s degree to $54,630 for a 15-year teacher with a master’s degree.

Brown said that left “quite a few” of the former SAD 34 employees without a salary increase, or even with a decrease when considering that teachers do have to pay part of the cost of their insurance and that portion is going up, too.

“Nobody’s going to agree to less take-home pay,” she said.

But Mailloux disagreed with this assessment, saying that no one would “go behind” in salary in the contract although some teachers might have spent two years without a step increase. There are 16 steps altogether.

“The initial goal for everybody was to create equity across the region,” he said, adding that it’s common right now for medical insurance costs to go up. “That’s happening everywhere.”

Brown said teachers just want to be treated equitably.

“We understand that there’s not all this money out there,” she said. “But we did expect there to be some fairness.”

Mailloux said he took issue with the idea that the rejected contract wasn’t fair.

“The goal … is to bring all teachers up to a common salary. In order to do that, some people are not going to get as much of an increase as other people,” he said. “I think this board has gone way out of its way to try to be fair.”

According to Mailloux, the three-member panel of arbitrators would bring together someone representing the association, someone representing the administration and a neutral party.

He said if things move quickly, the contract might be resolved in a month and a half. It is the first time in recent memory that the contract negotiation process has had to go to arbitration.