The public hearing last night in downtown Brooklyn over the Atlantic Yards project was intended to solicit comments on the proposed scope of a state environmental impact statement.

But the packed, and sometimes emotionally charged auditorium also served as an echo chamber for many of the arguments both for and against developer Forest City Ratner’s $3.5 billion proposal to erect more than a dozen offices, residential towers, a hotel, and a basketball arena in Prospect Heights.

Critics of the plan, who outnumbered supporters at the hearing, charged that the project is out of scale with the neighborhood’s character, and that it will increase noise, traffic congestion, eliminate open space; and limit parking, light, and air quality. They said the project would lengthen the emergency response times by police and firefighters and make the area more vulnerable to terrorist attacks.

Opponents asked that more criteria be included in the scope of the impact study, and that its area be expanded to include neighborhoods outside of the development’s 22-acre footprint.

Nearly an hour and a half elapsed before the first public supporter of the project, Reinaldo Torres, a representative of the sheet metal workers union, spoke. His message was simple, and caused loud rumbles of support from a group of union members gathered in the back of the auditorium. “Jobs,” Mr. Torres said. “We have a tremendous unemployment problem in this city. This Forest City Ratner, it’s the right way to go. He builds union 100% of the time.”

Another supporter, a black Brooklyn resident, Kwan Lewis, said he endorsed the project based on the jobs and housing it would provide for the black community. Brooklyn borough president, Marty Markowitz, called himself “a huge fan of the project,” but he cited concerns about the increased traffic and the project’s scale.

Council member Letitia James, of Brooklyn, an outspoken critic of Atlantic Yards, said, “This project is not about the economy. It’s about a developer, his investors, and their economy.”

The state agency in charge of producing the impact study, the Empire State Development Corporation, extended the hearing well beyond its scheduled 8 p.m. finish.

Based on the public comments, the ESDC will make revisions to the scope of the environmental impact statement. That statement, when completed, will outline necessary state and city approvals, predicted environmental impacts, and measures to mitigate those impacts. It will also list any unmitigated or unavoidable impacts and alternatives to the project.