Two men in their 40s have died after a collision involving a fuel tanker truck and another vehicle on Highway 407 in Vaughan.

The incident occurred around 5 p.m. on the eastbound lanes of the highway, near Keele Street.

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.

Shortly after the collision was reported, Ontario Provincial Police Sgt. Kerry Schmidt said that one of the vehicles was “fully engulfed.” Heavy black smoke could be seen drifting over the highway.

Schmidt told CTV News Toronto that it appears the crash occurred after one of the vehicles crossed from the westbound lanes into the eastbound lanes through a concrete barrier.

Schmidt said that police are on the scene collecting evidence in order to determine the cause of the collision.

“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,” Schmidt said.

The highway was shut down in both directions between Jane and Dufferin streets as emergency crews responded to the incident.

Jennifer Mitchel, a spokesperson for York Region, said in an email that three transport ambulances, a multi-patient unit bus, a platoon lead and a special response unit responded to the collision.

The tanker truck was transporting "a flammable liquid and caught fire," the City of Vaughan said in a statement.

In a statement issued at 7:30 p.m., the city said that the fire was under control and that “all emergency response units are working to ensure the safety and security of all residents.”

The city said that the smoke from the fire is covering a local industrial area, but that residential areas are not being impacted. The Ministry of the Environment and Ministry of Labour will be attending the scene “as a precautionary measure,” the city explained

The mayor of Vaughan tweeted about the incident, thanking emergency crews for their efforts in battling the flames.

“As media reports unfold, our thoughts and prayers are with those impacted by the devastating accident on Highway 407,” Maurizio Bevilacqua said on social media.

Schmidt asked drivers stuck on the highway to stay where they are and not to use the shoulder to try and navigate through traffic.

“If you are in a vehicle stuck in this closure, stay in your vehicle. Don’t turn around or try to drive someplace until you are directed to by police.”

The roads are expected to remain closed for several hours, Schmidt said, as police investigate the crash.