A vertical steel frame of a building collapsed this morning at a Science Park construction site, injuring four workers, one of whom was pinned to the ground by the fallen beam.

The New Haven Fire Department responded to the call and used training equipment to lift the beam off the worker, said city hall spokesperson Jessica Mayorga. That worker, along with two others, were transported to Yale New-Haven Hospital. The fourth worker, a female, was transported to St. Raphael’s Hospital.

Two of the male workers are currently listed in “critical condition,” while the other is in “serious condition,” said Yale-New Haven spokesperson Mark D’Antonio.

St. Raphael’s spokesperson Liese Klein ’88 said the female worker is currently in “stable” condition.

The frame, which collapsed around 10 a.m., was part of a chilling plant being erected by Shawmut Construction for Yale’s current expansion into Science Park. It is intended to provide 20,000 tons of cooling capacity for new Yale building projects in the area.

University spokesperson Tom Conroy could not be reached for comment.

This accident is the second construction mishap at the same site, Assistant Fire Chief Ralph Black said.