Two men were taken to hospital just after 9 p.m. on Friday after being hit and trapped by a light standard at Woodbine Park during the Beaches Rib Fest.
Firefighters removed the light standard and debris, and freed the two men.
One man is believed to be in his 40s and the other in his 30s, according to Toronto Fire District Chief Stephan Powell.
One of the victims was conscious and breathing and the other was slipping in and out of consciousness.
Police believe the high winds and thunderstorms may be a factor in the incident.
"The storm kind of rolled out of nowhere and the wind blew over the stage," said Chris Sullivan, who saw the incident. "The crew that was cleaning up the performer's instruments ... somebody got crushed under it."