A stretch of the Queen Elizabeth Way near St. Catharines remains closed in both directions after a four-vehicle crash early Thursday morning left two men dead and three others injured.

The incident happened at approximately 4 a.m., when two cars travelling on the QEW near Highway 406 in the Fort Erie-bound lanes collided with each other, Sgt. Dave Woodford told CTV Toronto.

"Two vehicles, a Mitsubishi and a BMW collided with each other," Woodford said.

Investigators are still probing the crash but say the collision set off a chain reaction, causing a tractor-trailer carrying steel coils to hit the Mitsubishi. The tractor-trailer then travelled across the median and went over the guard rail onto the Toronto-bound lanes of the QEW, spilling the coils onto the highway. A Toronto tanker carrying liquefied carbon dioxide then struck the coils.

A 20-year-old passenger in the Mitsubishi was pronounced dead at the scene. The 53-year-old driver of the tanker died from his injuries in hospital, OPP said.

The driver of the Mitsubishi and another passenger suffered life-threatening injuries and remain in critical condition. The driver of the tractor trailer suffered minor injuries.

Woodford said the liquefied carbon dioxide is not hazardous but officials continue to monitor the scene. He said the carbon dioxide is being transferred into another truck.

The force from the four-vehicle crash caused extensive damage, dislodging a 25,000 pound roll of steel that gouged the QEW.

The QEW is closed in both directions between Seventh Street and Hwy. 406 as police investigate the circumstances of the collision.

Woodford said Thursday afternoon that the OPP was in the process of opening up the Niagara-bound lanes of the QEW, but that the Toronto-bound lanes will likely not be opened until after midnight.

With files from CTV Toronto’s John Musselman and CP24