Two men in their 40s have been pronounced dead at the scene of a fiery collision on Highway 407 in Vaughan.

Ontario Provincial Police said a tanker truck and another vehicle collided on the highway, near Keele Street, at around 5 p.m. Wednesday.

The drivers of both vehicles, a 41-year-old man from Brampton and a 49-year-old man from Mississauga, were pronounced dead at the scene. Their identities have not yet been released.

The eastbound and westbound lanes of the highway have been blocked off between Dufferin and Jane streets as emergency crews respond to the incident.

“It looks like there were only two vehicles involved – the fuel tanker truck and another passenger vehicle,” OPP Sgt. Kerry Schmidt told CP24 from the scene.

For about two hours after the crash took place, the tanker truck remained fully engulfed in flames and heavy black smoke could be seen from quite a distance.

“It does appear that this collision was a crossover-type of collision, which is surprising on a highway that has concrete walls but you can see the damage and you can see the vehicles travel and obviously that is going to be part of the investigation,” Schmidt said.

“Witnesses have been reporting that a large vehicle went from the westbound lanes onto the eastbound sides and then caused a collision.”

The City of Vaughan said the tanker truck was “transporting a flammable liquid and caught fire.”

Schmidt said police are currently on the scene investigating the cause of the deadly crash.

“The investigators are on scene right now and as I was approaching the scene shortly after the collision took place, the sky was clear, there was no precipitation, the roads were dry, visibility wasn’t a factor so we’re going to be looking at all issues – whether or not it was human error, whether or not it was mechanical defect that may have contributed to the collision,” he said.

“The collision vehicles are now in the eastbound lanes but there is significant evidence on the westbound side and that’s why we have both directions of the highway shut down right now.”

Schmidt said the road closures will remain in place for “several hours.”

A spokesperson with York Region, Jennifer Mitchell, told CP24 in an email that three ambulances, a multi-patient unit bus, one platoon lead and one special response unit responded to the scene.

Vaughan Mayor Maurizio Bevilacqua tweeted about the incident shortly afterwards.

“As media reports unfold, our thoughts and prayer are with those impacted by the devastating accident on Highway 407,” he wrote. “We are grateful for the effort of our first responders battling the flames and bringing order to the situation.”