After a long and cold night, Toronto firefighters spent Thursday putting out the smoldering remains of a stubborn five-alarm fire that broke out at an East York frozen foods warehouse.

At the height of the raging blaze, officials considered evacuating the area because of fears the ammonia used to keep food cold was burning or could explode.

The measure wasn't necessary as a tanker truck arrived and workers siphoned off ammonia from several storage tanks. Residents who live near the facility, however, were told to stay in their homes and keep windows and doors closed.

The all clear was given Thursday morning after officials reassessed the situation.

The fire broke out at 209 Wicksteed Ave., in the Eglinton and Laird area, just before 7 p.m. on Wednesday night.

More than 100 firefighters and 25 fire trucks responded. Frigid temperatures added another problem as water turned to ice quickly, making it a slippery scene.

"We were doing some regular maintenance work and I saw the fire, so we tried to stop it, but it didn't stop, so we ran in and called the fire department," Matthew Alexander, whose family owns the cold storage facility, told reporters.

Three firefighters were treated for minor smoke inhalation.

Initial estimates put losses to the building at $3 million and lost product at $10 million. But investigators now believe those numbers will climb considerably.

The cause of the fire is not yet known.

The Ontario Fire Marshal's office is investigating.

With a report from CTV's Jim Junkin