BOSTON — A building partially collapsed at a Boston construction site Wednesday afternoon, injuring at least three people, one of them seriously, authorities said.

The collapse, with multiple people trapped, was reported around 1:45 p.m., a Boston police spokesperson said. The fire department’s technical rescue team also responded.

It occurred at a closed power plant in South Boston that is being redeveloped.

Boston Emergency Medical Services said in a tweet that two people were taken to the hospital and a third person, still being extricated, was also being treated.

“We have multiple units on scene for the structural collapse at the Edison Power Plant building in South Boston,” the agency tweeted.

Police said the injuries to one person were considered life-threatening.

The 15-acre site in South Boston is being redeveloped into a mixed-use property that includes residential, office, research and retail space, a hotel, and nearly 6 acres of new public open space, according to the Boston Planning and Development Agency.

The federal Occupational Safety and Health Administration is also going to the scene, a spokesperson said.

It was the second collapse at a Boston construction site this year. A construction worker died in March when a parking garage being demolished collapsed.