MISSISSAUGA, Ont. -- Police west of Toronto say a 39-year-old man suffered serious but non-life-threatening injuries in a "major explosion" Sunday morning.

Peel Regional Police say two other people -- a 43-year-old woman and a six-year-old boy -- were taken to hospital with minor injuries, while a 50-year-old man and a young child were treated at the scene and released.

The blast happened at a commercial complex in Mississauga, where Fire Chief Tim Beckett said it caused a major fire that he expected would take a while to get under control.

Mississauga Fire tweeted Sunday evening that crews were still on the scene, and advised people to stay clear of the area.

Police say a number of families have been displaced from the neighbourhood, and it's not clear when they'll be allowed to return home.

There's no word yet on the cause of the blast.