One construction worker died and three others were injured after a steel beam collapsed at a Yale construction site in Science Park on Monday morning.

The deceased worker, whose name has not been released, spent most of the day in critical condition at Yale-New Haven Hospital but died late Monday night, hospital spokesman Mark D’Antonio said. The accident was the second in five weeks to occur at 275 Winchester Ave. — the future site of a Yale chiller plant, which, when completed, will provide 20,000 tons of cool air to nearby Yale facilities.

The New Haven Fire Department responded to an emergency call, received at about 10 a.m. Monday, and used pressurized air-bags to lift the fallen beam off one of the workers at the site, City Hall spokeswoman Jessica Mayorga said. The pinned worker, along with the two other male workers, was transported to Yale New-Haven Hospital, and the fourth worker, a female, was transported to St. Raphael’s Hospital on Chapel Street.

D’Antonio said early Tuesday morning he did not know whether the deceased worker was the one who had been pinned by the beam. He added that one of the injured male workers remains in critical condition while the other is in “serious” condition.

St. Raphael’s spokeswoman Liese Klein ’88 said Monday evening that the female worker was in stable condition and was discharged from the hospital at about 4 p.m. The injured workers’ names were not released publicly, and Klein added that privacy laws forbid hospital officials from disclosing the type of injuries patients sustain.

The federal Occupational Safety and Health Administration office will investigate the incident within the next six months to see whether the site was in compliance with federal work-site safety regulations, said acting OSHA area director Paul Bernor. He said the agency is also investigating last month’s accident; if OSHA discovers that violations occurred in either case, the agency will issue citations to the parties found responsible, Bernor said.

Kelli McLeod, a spokeswoman for Boston-based Shawmut Design and Construction, the company erecting the building for Yale’s current expansion into Science Park, said Monday night that Shawmut did not have the information to be able to say what caused the beam to fall.

Shawmut CEO Tom Goemaat said in a statement Monday, prior to the news of the one worker’s death, that his company’s primary concern is the well-being of the injured workers.

“Our thoughts are with them and their families,” he said. “Job site safety is always our top construction priority, and we will cooperate fully with OSHA and local authorities in reviewing this very serious matter.”

University spokesperson Tom Conroy, reached by e-mail early Monday evening, called the incident “tragic” but said Shawmut is still a “reputable” firm that has done other projects for Yale. He declined to comment further at the time.

Richard Charney, whose company, New Haven-based Charney Architects LLC, designed the chiller plant, said Monday afternoon that he was waiting for the injured workers to receive treatment and for investigations to conclude before revisiting the construction site and assessing what went wrong.

Russell Hentz, a printing assistant at Yale Printing and Publishing Services, witnessed the accident and said he saw a male construction worker lose his footing while on top of the steel structure.

“He just went over backwards,” Hentz said. “He went, and the girders all came after him.”

Hentz said he saw another worker trapped in a cherry picker at the construction site when the beam fell.

Last month, another cherry picker tipped over in the basement area of the construction site, injuring another construction worker.

New Haven Assistant Fire Chief Ralph Black said that having two similar accidents within one month’s time is “concerning.”

U.S. Rep. Rosa DeLauro, who represents New Haven, released a statement Monday evening about the morning’s incident.

“My thoughts and prayers go out to the injured workers and their families,” DeLauro wrote.

Conroy did not immediately respond to a request for comment Monday night about whether the incident would delay construction on the chiller plant, which is part of the University’s plan to develop the Science Park area.

Massachusetts-based real estate investment firm Winstanley Enterprises purchased the site of the chiller plant, as well as the adjoining 25,000 square foot parking garage and office space, from BioMed Realty Trust for $14.5 million in 2007.