Neighborhood group, developers close to agreement on 15-acre Union Square project

A rendering depicts the first phase of a massive development proposed for Union Square in Somerville, along Prospect Street, — near the MBTA Green Line station that is scheduled to open in 2021.Union Square Associates

The developers behind the long-planned redo of Union Square in Somerville might finally be making peace with their new neighbors.

The real estate firm US2 and negotiators for the Union Square Neighborhood Council said this week that they have agreed in principle on a broad package of community benefits tied to the 15-acre project — including affordable housing, hiring rules, and public space.

If the broader council — whose members include people who live or work in Union Square — votes to approve the deal, it could kick-start more than $1.5 billion worth of development around a new MBTA Green Line station on the east side of Somerville.

Neither party would discuss terms of the deal until it is made public at a meeting later this month, but they said it will spell out US2’s obligations across a wide range of areas, including union labor rules, workforce training, and opportunities for small businesses. It has been hammered out in a series of closed-door meetings over more than a year. Negotiators said they were hopeful the agreement would address an array of concerns residents of the fast-changing neighborhood have about the project.

“We’re not yet at the end of the road,” said Ben Bradlow, an elected member of the Neighborhood Council’s board who served on its seven-member negotiating committee. “But this is pushing toward what would be the culmination of many years of activism in the community, and a process whereby the neighborhood council engaged over 150 residents, and a wide range of organizations, to develop the priorities that guided the negotiating team.”

The neighborhood vote, which may come in early fall, could also free US2 to start building — more than five years after the Chicago company won development rights for Union Square.

Several members of Somerville’s City Council have blocked the transfer of a key piece of land to US2 until a community benefits agreement is ratified, and the project remains before the city’s Planning Board, with a meeting on it scheduled for Thursday night.

Amid the delays, US2 has pushed ahead with planning for a three-building first phase, which last week won state environmental approval. It has lined up investors and signing partnerships with the development company Skanska USA and Cranshaw Construction. It would like to start work this year, a spokeswoman said, and aims to have buildings done around the time the Green Line extension reaches Union Square in 2021.

“We are excited that we have come to an agreement in principle and look forward to finalizing the details and a community vote in the very near future,” said Greg Karczewski, president of Union Square Station Associates.

An affirmative vote, however, is not guaranteed.

While benefits packages for big developments are typically negotiated by city officials, in this case Union Square activists successfully lobbied Mayor Joe Curtatone to let the newly formed Neighborhood Council take the lead, and to put the final package up for a vote of its membership. It includes a broad coalition of longtime Somerville residents, newcomers, business owners, labor activists, and environmentalists. Bradlow said the negotiating committee worked hard to craft a deal that will appeal to all of them, while recognizing they couldn’t get everything they wanted.

“We’ve been quite explicit about the need to negotiate an agreement that we feel can be approved by our members,” he said. “We’ve made that very clear.”