Officials are still investigating what caused a blaze inside a north side ice plant Wednesday evening.

Firefighters were called to the Arctic Glacier plant at about 7:20 p.m. Wednesday, after a passerby noticed smoke rising from the building, located at 121 Avenue and 121 Street.

Crews arrived to find black smoke pouring out of the building – and crews had a difficult time getting into the building to find the source of the blaze.

“Due to the type of business this is they have extra insulation inside there,” District Fire Chief Bill Brown said on the scene, he said there’s a chance some new equipment could be to blame.

“Some new air conditioning and freezing units on site might have been the cause, we’re not sure.”

Brown said the blaze was contained to a packing area where plastic packaging is kept.

As a result, the smoke from the blaze was considered toxic, and residents living within a few blocks of the building were evacuated for about two hours as a precaution.

“[There were] a lot of polymers burning inside the building, we were worried about the plastic packaging they use to package up the large ice blocks,” Brown said.

On Thursday morning, an Edmonton Fire Rescue spokesperson told CTV News the cause of the blaze is still under investigation, although much of the fire was concentrated in foam insulation in the building’s walls and ceiling.

Damage was pegged at $500,000.