TOWNSEND -- The North Middlesex Regional School District is one step closer to getting a new high school.

The proposed design for a new $89 million high school was approved unanimously by the Massachusetts School Building Authority this morning at its board meeting in Boston.

The MSBA is expected to reimburse about $40.2 million of the project cost, with the rest of the cost falling to district member towns Ashby, Pepperell and Townsend.

"When you put it in perspective, the MSBA just awarded our community a $40 million grant if the voters choose to go that way, which doesn't happen often," said Robert Templeton, chair of the high school building committee.

"It's a fantastic opportunity for the community to build something that's going to last for 50 plus years and really take the ability to educate our students to the next level. I'm thrilled for the district to get the opportunity," he said.

The approval was given after some adjustments were made in the project in recent months, including the removal of an expanded gym from the project upon MSBA request.

Templeton said the MSBA required that the expanded gym not be included as it did not have a direct impact on students' learning during the school day.

State treasurer Steven Grossman, who also serves as the chairman of the MSBA, said in a statement Wednesday that the project is a "down payment" on the academic excellence of North Middlesex students.

"Upon completion, this new school will provide a modern learning environment and create the space needed to deliver on the school district's educational commitments and goals," the statement read.

The project will now go before voters at a series of Special Town Meetings in March. Pepperell will vote on March 10, Townsend on March 11 and Ashby on March 15.

If each town passes the project with a two-thirds majority, a debt exclusion vote will then need to pass in each town's annual election on April 28 for the project to go forward.

"I'm confident that we can get the right amount of information out to make sure that the taxpayers of the district are well-informed of the project. I know that the real work starts now, but our job is to put the facts out there, and now it's up to the voters," Templeton said.

The building committee has sent mailings out to all households in the district with information about the project, and will be hosting a series of presentations on specific parts of the new building plan and tours of the existing high school in the weeks leading up to the Special Town Meetings.

A community forum will be held at North Middlesex Regional High School on March 5 at 7 p.m.

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