A man who survived a two-alarm fire at his downtown Toronto apartment is likely only alive because of his quick-thinking roommate, who ran barefoot into the burning building to save him.

The fire closed a section of Queen Street West to traffic Monday morning and sent one resident to hospital with second- and third-degree burns to 45 per cent of his body.

The fire broke out just after 6 a.m. on the third floor of a building on Queen Street West just west of Spadina Avenue, near Cameron Street.

"I ran downstairs. I didn't even have time to think, man. No shoes, no shirt, nothing," Pavel Tosiek, who lived in the apartment, told the CBC's Trevor Dunn. But after he escaped the blaze, he heard "really loud screaming."

One of Tosiek's roommates was in the building. Tosiek ran barefoot back inside the burning building, and he found his friend barely conscious, his clothes still on fire.

"And he was struggling, but he was stuck, so I grabbed him and pulled him and I yanked him and I dragged him down the stairs," Tosiek said.

Tosiek says his friend's nylon shirt was melted to his skin.

'He could very well be a hero'

"He could very well be a hero," said Toronto district fire chief Dan Sell. But he cautioned that it isn't always a good idea for civilians to enter a burning building.

In this instance, Sell said, a life was saved.

"[The burn victim] would have been a fatality right off the bat," he said.

Toronto firefighters say the victim's injuries could have been avoided.

Early investigation shows the cause of the fire was an overloaded electrical outlet, and the apartment had no working smoke detectors.

The building, located adjacent to the Cameron House bar, houses a hardware store at street level and apartments on the floors above.

The fire was contained shortly after 7 a.m. on Monday.

The TTC diverted streetcars around the area in both directions before Queen Street was re-opened to traffic shortly before 8:30 a.m.