TIVERTON — Nearly 200 teachers reported to work yesterday for the first day of classes in the new academic year, while union leaders scheduled a membership meeting for tomorrow after school to discuss the status of contract negotiations.

At the same time, the School Committee and the union fired salvos at each other while each side waited to hear about the start of a compulsory mediation process from the state Department of Labor and Training.

The School Committee has formally rejected a proposal of the National Education Association-Tiverton for an alternate health-care plan that features a high deductible and a health-care savings account, contending it would increase the cost to taxpayers.

The union has said its plan would save the district $186,000 in the first year, according to a statement issued by the committee yesterday, but it has offered no substantiation of possible savings in the second and third year.

Union spokesman Patrick Crowley replied, “It’s unfortunate that the School Committee has not taken the time to do the math accurately, and in addition to our mediation request we’re going to suggest that they get math remediation as well.”

He did not directly address the figures quoted by the School Committee.

In a statement, the committee chairwoman, Denise deMedeiros, said the union’s most recent proposal was discussed in a closed session Tuesday night.

The committee said it has asked the union to respond to the committee’s health-care plan, which would move from a flat rate contribution by each employee to a sliding scale payment based on salary.

Teachers at the lowest end of the 10-step pay scale would pay 15 percent of their health insurance premiums, teachers at the middle levels would pay 20 percent, and those at the high end would pay 25 percent, according to the committee statement.

The statement did not say that the committee’s health-care plan would save the taxpayers money.

Union spokesman Crowley, meanwhile, said the committee’s own fiscal analysis disproves its assertion that the union’s proposal would cost more.

Even if one accepts the committee’s calculations at face value — and the union does not — its own statement says that there is a minimum projected savings of nearly $24,000 in the teachers’ plan, Crowley said.

Crowley is deputy executive director of the National Education Association-Rhode Island, the state affiliate of the Tiverton teachers’ union.

Neither deMedeiros nor Schools Supt. William J. Rearick was available for questions last night about the committee’s statement.

Last week, Crowley said the union requested compulsory mediation to force School Committee members to come to the bargaining table. Rearick, the chief negotiator, has not had the authority to reach a tentative agreement, Crowley said.

In the statement, deMedeiros said the committee believes that the negotiation process has been “relatively smooth and very productive.”

The superintendent has done an excellent job in expressing our position to NEA–Tiverton and relaying their concerns to us,” she said.

gmacris@projo.com