A four-alarm fire broke out in a food processing plant in the East York area of Toronto Wednesday evening, worrying emergency crews due to concerns about a potential ammonia leak at the scene.

Firefighters reported just before 7 p.m. that the fire was in the ceiling of the plant, which is in the Eglinton and Laird area. Flames could not be seen from the outside but a large amount of smoke was billowing from the plant.

Firefighters battled the blaze in the building's north end and tried to get their bearings due to heavy smoke at the scene. They also reported seeing a large quantity of food inside the structure.

Ammonia, which is used as a coolant in the plant's refrigerators, caused emergency crews to bring a hazardous materials team to the scene.

An evacuation of the area was not ordered while fire crews tried to determine if ammonia was leaking. However, firefighters asked that trains scheduled to run along a nearby railway line be rerouted.

With a report from CTV's John Musselman