Firefighters said Wednesday that they would let the fire burn through the night. (CBC)

Two people were killed in a fiery crash between a tanker truck and a pickup truck on the Trans-Canada Highway in northern Nova Scotia early Wednesday afternoon.

Police, paramedics and several fire departments were called to the scene of the crash, which occurred on Highway 104 near Kenzieville in Pictou County.

It's believed the trucks collided head on, setting fire to the used motor oil the tanker truck was carrying in the process.

Both drivers were killed, but no details about them have been released. The body of one of the drivers was found in the woods near the highway.

A cloud of dark, black smoke could be seen billowing from the crash site from several kilometres away.

A hazardous waste team was brought in from Truro, but firefighters said they will not put water or flame retardants directly on the fire for fear that the oil could flow into the nearby Barneys River.

The fire was still burning late Wednesday afternoon and could continue to burn through the night. It is being monitored to ensure it does not spread to nearby trees.

Highway 104 is closed between exits 27 and 29 and will remain closed overnight. The Department of Transportation is re-routing traffic along Highway 4.

Explosions from the fire could be heard from kilometres away and the smoke was so thick and intense the tractor-trailer wasn't even visible in the bushes at the side of the road.

The smoke from the fire could be seen in three surrounding counties.

Merigomish Fire Chief Paul Schnurr said he was worried about the contents of the smoke, so crews were trying to stay upwind of it.

Police will investigate the collision but won't be able to do so until the fire burns out.