The fire with three alarms was first reported around 3:40 p.m.  at a company near Racine Road and Brydon Drive, close to Kipling Avenue and Rexdale Avenue.
Fire Chief Matthew Peg said on arrival the crews encountered “a strong fire that hit a series of propane and compressed gas cylinders outside the building” and immediately took up a defensive position.
He said the fire eventually spread to several parked vehicles, but crews were able to bring it under control before it spread to the building itself.
“These are very complex, complicated and dangerous fires for our crews, as they have to get close enough to develop ground-based monitors – unmanned water flow monitors – and overhead towers, the main goal of which is to keep these cylinders cool.” he said.  “I am pleased to say that the fire is now under control and there are no reported injuries.”
Pegg said he was told some of the propane tanks outside the business weighed up to 100 pounds.
There were reports of explosions as the fire was burning, although crews have not yet determined whether any of the propane tanks actually burst.
The cause of the fire itself remains unclear.
“It is very difficult to tell when the incident is alive, whether it is an explosion or the relief of a pressure relief valve.
Police are at the scene of the fire and explosion in Etobicoke.  (Sean MacInnes / CTV News TOronto)
Any flammable gas cylinder or compression cylinder is equipped with a pressure relief valve, so in the event of heat impact, the pressure relief valve will release.  “It will release gas, there will be ignition of this gas, but it is designed to prevent the actual explosion of this cylinder,” Pegg said.
“So it is very likely that initially there was gas evaporation, there would be several sounds that sounded like an explosion and part of our responsibility as soon as we completely extinguish the fire will be to make the source and trigger an investigation to determine if there was an explosion or not, but it’s too early to confirm. “
At the height of the fire there were about 30 different devices and 100 firefighters at the scene, but Pegg said the response has since been reduced.
He said it was a “very provocative incident” that could have been “very important” had it not been for the actions of Toronto firefighters.
“It was absolutely well managed and it was brought under control very quickly,” he said.
Racine Road remains closed between Martin Grove Street and Kipling Avenue as a result of the fire.