Emergency crews received numerous calls around 5:45 a.m. from drivers on the DVP who reported a large area on fire west of Lake Shore Boulevard and the Don Roadway.
There were also reports of several propane canisters exploding, officials said.
A spokesperson for Toronto fire said it was difficult to access the scene of the blaze and it took crews nearly 30 minutes.
Firefighters ended up using a bike path to access the scene and the fire was then quickly extinguished, the spokesperson said.
Four people were injured in the blaze, two of whom suffered mild smoke inhalation, the spokesperson said.
There is no word on the severity of the other two victims’ injuries.
Crews remained at the scene into the morning Sunday as they investigated what led to the blaze.