A four-alarm fire continues to burn at a commercial building near Dupont Street and Dundas Street West after forcing some residents from their homes and students from a school, and closing several streets in the city’s west end earlier Monday.

Firefighters continue to battle the stubborn blaze from a defensive position outside the building, a self-storage facility located at 97 Pelham Ave. at Osler Street.

For a brief period, the fire was raised to five-alarm status.

Firefighters will remain on the scene through the night to battle small spot fires believed to be burning inside, Mike McCoy of Toronto Fire Services said.

A mayday radio call was made shortly after 2:30 p.m. after a firefighter fell through the third floor of the building.

He was taken to hospital as precaution, but his injuries are believed to be minor.

St. Josaphat Catholic School and some homes in the area were evacuated as a precaution. The school’s staff and students were moved to St. Luigi Catholic School at 2 Ruskin Ave.

The school will remain closed Tuesday as a precaution, a release from the Toronto Catholic District School Board said.

Parents may call 416-222-8282 ext. 5314 or 416-393-5291 for further updates.

Firefighters aren’t entering the building due to several concerns, including fears the building may collapse.

Fire crews encountered heavy smoke when they responded to the four-storey warehouse at about 6:15 a.m.

They soon encountered several challenges, including the building’s high security features and "deep-seated burning" of debris, which required foam to extinguish.

Foam is a wetting agent that helps to break down the surface tension of water and allows for deeper absorption by the burning materials, Toronto Fire Services said.

As the fire burned out of control, flames shot out of windows and a huge plume of smoke drifted into the sky.

Because of the blaze, Pelham Avenue, Osler Street and part of Uxbridge Avenue are closed.

No injuries have been reported.

The Office of the Ontario Fire Marshal has been notified of the fire, and will likely be on scene tomorrow morning, Toronto Fire Services Chief Bill Stewart said.

(Click here to view a photo gallery of firefighters battling the blaze)

GO Transit said service on its Kitchener Line has resumed following an earlier disruption that delayed a Toronto-bound train from Kitchener for about two hours.