Fire departments were called to the Bay Village Condos, a 129-unit complex in Irondequoit where two construction workers were injured, one of them seriously.
The Irondequoit Fire District says a 40-by-150 foot wooden structure collapsed while it was being used in work on a two-level parking garage.
Two workers were trapped and were freed by the time first responders got there.
One worker was treated on scene and went back to work, but the other suffered traumatic injuries and was sent to Rochester General Hospital.
No residents of the complex were affected by the accident, which is being investigated by the town engineer.