Two people are dead and two others are in critical condition following a serious crash involving several tractor trailers near the town of Sutton.

According to Ontario Provincial Police, the crash unfolded on Highway 48 near Old Homestead Road in the municipality of Georgina shortly before noon.

The multi-vehicle crash involved three transport trucks carrying gravel, one commercial vehicle and one passenger car.

Two people were pronounced dead at the scene, according to OPP.

ORNGE Air Ambulance told CTV News Toronto that two helicopters were requested to attend the scene.

One air ambulance transported a child to Sick Kids Hospital in Toronto and a second air ambulance transported an adult victim to Sunnybrook Hospital.

Georgina Fire Chief Ron Jenkins said that at one point, firefighters required heavy machinery to help extricate at least one of the victims.

“Our crews had a very, very challenging rescue. They had to tunnel into the vehicles to get to the patients themselves,” Jenkins told CP24.

“The devastation and damage to these vehicles is extreme.”

Jenkins said the injured child was an occupant of the passenger vehicle. It’s not yet clear what vehicles the other victims were in at the time of the crash.

Two firefighters were also transported to hospital from the scene due to the heat and humid conditions, according to York Region Paramedic Services.

Video taken from the CTV News Chopper shows debris scattered across the highway and an adjacent grassy area.

OPP Sgt. Kerry Schmidt said the scope of the wreckage is “massive.”

“This is one of the most devastating crashes I’ve seen in a long time,” he said. “It is absolutely incredible the amount of trauma that these vehicles have sustained.”

Schmidt said investigators are now working to determine what led up to the multi-vehicle crash.

“There may have been construction up ahead. There may have been slowing traffic,” he said.

“There are still a lot of questions that need to be answered. I want to leave it to the investigators to ensure they get it right.”

Highway 48 has been closed between Old Homestead and Lartimer roads as emergency crews tend to the scene.

It’s expected the highway won’t reopen to traffic for another eight to ten hours.

“It was horrific,” Jenkins said of the scene.

“When you see the sheer force and damage that it can do to vehicles…It’s somewhat disturbing but that’s what we do on a day-to-day basis.”