Mattapoisett selectmen are concerned about a multimillion-dollar liability at the Old Rochester Regional and are hoping Rochester and Marion will collaborate with them on a solution.

According to Town Administrator Mike Gagne, the school has a $21.3 unfunded health insurance liability, commonly called other post employment benefits or OPEB. Gagne said, the liability has grown by $8.2 million since 2013. All three towns already have trusts set up to address their own OPEB liabilities, and last year Mattapoisett set aside funds for its portion of ORR’s liability.

One issue, however, is that there’s no clear understanding of how the three towns should divvy up that responsibility. Selectmen are also concerned with ORR's general budget, including the teacher contract approved by the School Committee last year.

The committee says teachers only received a two percent increase, but Selectman Paul Silva said ORR teachers also get a pay raise every year for their first 12 years, along with pay increases for things such as increasing their education.

“They only talk about their contract increase,” Silva said. He said the pay increase averages to four percent. “Some people are getting more than four, some are just getting two.”

ORR School Committee Chair Tina Rood recently said that the salary increases at ORR are below the state average, and that in the previous teacher negotiations, faculty took a hit by seeing more of an increase in their health insurance costs than they did in their salaries.

She’s also maintained that it is the job of tri-town selectmen to improve the town’s tax base, thereby reducing the budgetary strains.

On Tuesday, Gagne suggested that the towns hire a third party to evaluate the school’s finances from the past five years, and going forward, set out guidelines for benefits, salaries and funding the OPEB liability.

He proposed the towns appropriate $10,000 each at their upcoming town meetings to hire an advisor.

“I think it’s well advised,” said Selectmen Chair Tyler Macallister. “We need to start taking a look at the OPEB liability but also getting the business of the school functioning healthy again.”