AMHERST — Town officials will have until the end of March to hire a general contractor to handle the $46.1 million expansion and renovation of the Jones Library.

The Massachusetts Board of Library Commissioners voted unanimously Thursday to approve a request from Austin Sarat, the president of the Jones Library trustees, and Town Manager Paul Bockelman to give the town time to get through a mandated federal historical review known as the Section 106 process.

The only commissioner who spoke before the vote, George Comeau, cited the support for the extension from state Sen. Jo Comerford, D-Northampton, as well as state Rep. Mindy Domb, D-Amherst, and what he characterized as unusual advocacy by U.S. Rep. Jim McGovern.

“What swayed me the most was the local leaders who stepped forward in the last 48 hours, the state senator stepping forward — this is where we derive our support in the Legislature, it’s where we derive out support in Congress,” Comeau said.

But he also acknowledged the 135 pages of emails supporting and opposing the project.

“It’s a spirited debate, as is pointed out,” Comeau said. “But our work here is to move libraries forward.”

The request for the extension came following a series of cost-cutting measures over the summer, and a recently received $35.77 million construction bid from Fontaine Brothers Inc. of Springfield, for the $46.1 million project. The low bid is $231,000 below the advertised cost of the work and, factoring in project expenses to date and contingency costs, the low bid places the total project cost about $1.6 million under the bond cap approved by the Town Council.

The appeal from town officials for the extension references the Section 106 process that’s required to access federal grants for the project, including a Challenge Infrastructure and Capacity Building grant from the National Endowment for the Humanities and an Economic Development Initiative grant from the U.S. Department of Housing and Urban Development. The Section 6 review is also needed for the project to secure a hazardous waste removal permit from the Massachusetts Department of Environmental Protection.

The federal Section 106 review considers the impact to historical features of the existing library. The expansion project calls for removing some of the building’s historic millwork and several staircases, and altering other historical features.

Comeau said he is comfortable that the Massachusetts Historical Commission, which is participating in the federal review, is doing its due diligence, refuting concerns from some opponents. He also said the MBLC is not putting public money at risk, calling that “an unfounded allegation.”

In a unanimous vote in June, the MBLC granted an extension to the deadline for hiring a contractor for the project through the end of the year after the initial bids came in at least $6.5 million beyond what the town could afford for enlarging the building from 48,000 square feet to 63,000 square feet, overhauling mechanical systems and doing other renovations.

Andrea Bono-Bunker, a consultant for the MBLC, explained that a second payment for the project was withheld because a milestone in the project’s development was missed. But she said a double payment owed to Amherst will come now that it has secured a bid within the funding authorization.

This is the last opportunity to make that double payment without compromising the MBLC’s building program’s fiscal health, she said.

No Amherst officials spoke during the meeting, though numerous officials were present virtually, including Library Director Sharon Sharry and Town Council President Lynn Griesemer.

Sharry, participating via Zoom, could be seen silently clapping following the tally of the vote.

Scott Merzbach can be reached at smerzbach@gazettenet.com.