By Tim Logan

It looked like smooth sailing for a bill that would allow more shadow on Boston Common and help clear the way for a new downtown skyscraper. Until Secretary of State William F. Galvin spoke up during a State House hearing Tuesday.

Galvin asked lawmakers to delay for at least two weeks a vote on changing the existing shadow law — until the Massachusetts Historic Commission, which he oversees, has time to study the building’s impact on the Common, Public Garden, and other historic downtown sites.

“This is not something that should be done recklessly,” he said. “It’s a very significant piece of legislation.”

After the meeting, the chair of the committee considering the bill agreed to the delay, slowing what had looked like a fast track to approval for the bill, which is key to Millennium Partners’ billion-dollar tower proposal for the site of the Winthrop Square Garage — and the $153 million the developer has agreed to pay the City of Boston to buy it.

But it’s still unclear whether the powerful Beacon Hill insider’s concerns amount to a speed bump or become a bigger obstacle for the complex project.

Galvin said the Historic Commission hasn’t had time to review shadow impact studies it received late last week. He also said he’s hesitant to undo a law that has protected the historic parks for more than 25 years. His agency has broad latitude to review development projects that affect historic buildings. During his tenure Galvin, has occasionally held up projects for that reason, sometimes for years.

The Winthrop Square tower, however, appears to enjoy broad support, especially since the Boston City Council approved changes to the shadow laws by a 10-3 vote in April. Once vocal critics of the project — Friends of the Public Garden and Neighborhood Association of the Back Bay — have adopted a more neutral tone. Key state lawmakers, previously noncommittal, havesponsored the shadow measure. And a parade of supporters testified at the public hearing Tuesday about the jobs, affordable housing, and revitalization opportunities the project would create.

Millennium and city officials have spent months cultivating support for the tower, especially sinceit became clear in November that they would need to change state laws governing shadows cast on public parks. The Walsh administration has earmarked most of the $153 million sale proceeds for funding parks and public housing across the city.

After the months of public discussion, Brian Golden, director of the Boston Planning & Development AgencyQ, said he was surprised that Galvin is only now airing his concerns. Golden said he would be glad to share any information that the secretary of state requests.

Joe Larkin, the Millennium executive who’s leading the project, said he, too, is willing to meet with Galvin to address any issues.

“We’ll sit with him, show him our studies and what we want to do,” Larkin said. “I’ve never actually met the man. I look forward to it.”

Comment