At least seven people were injured when the four-story concrete facility -- which was under construction at Miami Dade College's West Campus -- collapsed just before noon Wednesday, The Miami Herald reported.
College spokesman Juan Mendieta said all the victims were employees of Ajax Construction, the lead contractor on the project. Mendieta said several subcontractors were working on the structure, which had been scheduled to open in December.
Miami-Dade Fire Rescue Capt. Louie Fernandez said rescuing the final trapped worker could take an extended period of time because of all the debris surrounding him, WPBF-TV, West Palm Beach, reported.
Rescuers had to wait to search for victims until portions of the structure -- which collapsed "pancake" style -- could be shored up, the Herald said.
"Right now, we're doing a head count to see how many people are missing," Doral Police Chief Ricardo Gomez said earlier. "The issue is the structural integrity of the garage has been compromised to the point that it's unsafe to get into the garage."
Miami-Dade Fire-Rescue was performing triage on-site and injured workers were treated for shock and trauma at Jackson Memorial Hospital.
The campus was evacuated and some roads in the area were closed, the newspaper said.