A massive fire broke out at a construction site in front of a senior’s home in the Streetsville area of Mississauga, triggering explosions and forcing the evacuation of some residents for hours.

The three-alarm blaze started around 7 p.m. in the area of Tannery Street and Joymar Drive, near Queen and Thomas streets.

At the height of the blaze, approximately 15 fire trucks and 60 firefighters were battling the blaze, which destroyed a four-storey building under construction.

Residents say they heard several explosions and saw huge plumes of smoke fill the night sky.

Madalena Ferreira, who lives about one kilometre away, told CityNews she heard “bomb sounds.”

“I saw this huge ball of flames … it was one of those things you can’t believe when you see it,” she said.

“The whole sky was orange … it totally lit up the sky.”

Jennifer Lavergne was having dinner at a nearby restaurant when patrons began rushing to the windows.

“We looked out the window and saw clouds of smoke … and we heard a boom, an explosion kind of sound,” she said. “Within about 15 minutes it was fire, ambulance, police.”

The ruins of a building destroyed by fire is seen in Mississauga on March 3, 2018. CITYNEWS/Hugues Cormier

Late Saturday morning, Mississauga Fire Chief Tim Beckett said crews had to cut power to the area and were working to restore it by the early afternoon.

There were safety concerns due to possible structural collapse and live wires, he added.

A firefighter injured his hand when he slipped and fell on the ice, but there were no reports of any other injuries.

The cause is still under investigation.