Homes and businesses near an asphalt factory had to be evacuated Saturday as fire crews battled a potentially toxic blaze since the early morning.

"Now this has been quite a challenge because we're dealing with toxins that are potentially going up in the air," said CBC's Ivy Cuervo from outside the Oshawa, Ont., warehouse — located east of Toronto.

Oshawa fire services received a call about a fire at McAsphalt Industries, which contains rubber and plastic products, shortly after 5 a.m. ET. An internal alarm notified the firefighters, who arrived on scene shortly afterward.

Black, thick, billowing smoke from the fire could be seen kilometers away, blowing across Highway 401 and drifting towards Oshawa, and the nearby communities of Courtice and Bowmanville.

A view of the smoke from a fire at an Oshawa, Ont., industrial plant from a car heading westbound on Highway 401. (Twitter)

Darren Carl, who was driving on the 401 told CBC News he could see the smoke as far away as Bowmanville. Asked to describe the smell he said it's a very "thick odour" and it smelled like burning asphalt or rubber.

Officials from the Ontario Ministry of the Environment were on scene to test the air quality.

As health officials warned the smoke could contain carcinogens, local residents were asked to close their windows as a precaution. Homes and businesses directly in the smoke's path had to be evacuated.

Firefighters will likely be battling the fire throughout the night and into Sunday, said Oshawa Fire chief fire prevention officer Susan King.

"As long as the fire is burning there will be smoke," King said.

The McAsphalt plant is at the corner of Farewell Street and Harbour Road. It is located near the GM plant and an animal sanctuary.

There have been no injuries reported, and it is currently unclear what caused the fire.