Office tower OK’d for Hood Milk plant site in Charlestown

An artist’s endering of a proposed office building on Stack Street in Charlestown, on the former Hood site.SMMA

The huge former Hood Milk plant in Charlestown could soon become a hub for a new industry.

The Boston Planning & Development Agency on Thursday approved plans for a 232-foot office tower on Stack Street in the complex between Rutherford Avenue and Interstate 93. It would will likely house a major expansion by Indigo Ag, a fast-growing plant-science company that occupies a smaller building on the site.

Indigo hasn’t yet signed a lease for space in the building, but executives with the company spoke in support of it at BPDA’s board meeting Thursday, saying the tower would give them room to keep growing in Boston.

“We’re very excited about it,” said Larry Weiner, head of global real estate for Indigo Ag, which has about 400 employees in Charlestown and last year raised $250 million to fund continued expansion.”We’re growing very quickly, and we need someplace to go.”

The office tower, which could break ground later this year, is the next step in a full-scale makeover of the former milk plant that shuttered in the 1990s into a 20-acre campus of housing and office buildings, park space, and a hotel. Developer Catamount Management is planning eight new or expanded buildings with about 1.1 million square feet of new development in all, plus an apartment building and garage already under construction.

It considers the campus — close to downtown, near an Orange Line stop and in a corridor of the region between North Station and Assembly Row that’s undergoing rapid growth — a potential destination for growing companies.

“We’re really trying to transform the nature of Hood Park,” said Mark Rosenshein, who’s working on the project for Catamount.

The BPDA Thursday also approved Catamount’s latest version of the broader Hood Park plan, which will enable taller buildings along Interstate 93 but also open more space at the street level, including a one-plus-acre park, dubbed Hood Green, on D Street.

As part of the plan, Catamount also agreed to make a variety of improvements to the site. The company will contribute roughly $2.2 million in transportation funding for the area, including new bike lanes and an improved crossing for cyclists and pedestrians on busy Rutherford Avenue. It will also raise the ground level at the site — which is vulnerable to flooding from sea level rise — by two to five feet, and plans to install electric cogeneration.

In addition, Catamount said it will add affordable housing in excess of the city’s required 13 percent for new units, and will fund a variety of community programs.

Other projects to win BPDA board approval Thursday included a 254-unit building in West Roxbury, a 228-unit apartment and condo building in Brighton, and smaller residential buildings in East Boston, South Boston, Jamaica Plain, and Hyde Park.

The board also gave its blessing to redevelopment of the long-vacant Alexandra Hotel in the South End as a boutique hotel, though more approvals remain for that project.