A 27-year-old man is in hospital with severe burns that he suffered before his roommate rescued him from a burning building early Monday morning.

The fire victim suffered third-degree burns to almost half of his body, a Toronto EMS spokesperson told CP24 after paramedics responded to the blaze on Queen Street West, just west of Spadina Avenue.

The two-alarm blaze broke out in a building at 410 Queen St. W., which is home to Jacobs Hardware and apartments, at about 6:15 a.m.

Pawel, a man who lives in the building, is being hailed by police for saving his roommate as the fire burned out of control on the third floor.

Pawel said the building was engulfed in flames when he and others ran outside, but he soon realized his roommate was trapped upstairs.

Pawel re-entered the burning building and found his friend at the doorway of their apartment.

"His legs were stuck on the beam of the doorway and the hallway, so I had to literally pull him and grab his legs, and pull him really hard and drag him down the stairs," Pawel told CP24 at the scene.

Firefighters arrived a short time later to extinguish the blaze and prevent it from spreading to neighbouring buildings.

Cause of fire may be electrical in nature

The cause of the fire is under investigation, but a preliminary investigation determined the fire may be electrical in nature, said Toronto Fire Services district chief Dan Sell.

Sell said investigators traced the origin of the fire to an overloaded power bar in a bedroom where the injured man was sleeping.

Sell said the building's smoke detectors weren't functioning when he arrived at the fire scene.

He said smoke detectors were installed in the hallways of the residential portion of the building, but not in the suites themselves.

This is at least the second fire in as many weeks to destroy or damage a building on Queen Street West near Spadina Avenue.

In late October, an early-morning fire destroyed a building at Soho Street that housed a Roots store, hair salon and tattoo shop.

With files from CP24 reporter Cam Woolley

@ChrisKitching is on Twitter. Don't forget, for instant breaking news, follow @CP24 on Twitter.