Highway 401 near Cambridge was closed during Thursday morning’s commute after a rear-end crash sent seven people to hospital, one of whom suffered critical injuries.

OPP say shortly after 3 a.m. an SUV slammed into the back of a five-tonne truck in the eastbound lanes of the 401 near Highway 6.

Police believe the truck was travelling east in the middle lane when it was rear-ended by the SUV, which they say may have been speeding.

Police say the truck then spun onto the right shoulder of the highway, where it got caught up in the guardrail.

Five people were travelling in the SUV and two people were in the truck. All of them were taken to hospital.

Police say one of the SUV passengers was ejected from the vehicle.

“The woman being ejected we are looking at seatbelt use on that,” said OPP Sgt. Kerry Schmidt. “Alcohol may be a factor as well, we’re looking into that, and whether distraction or inattention may have played a part.”

There was a significant amount of debris at the scene and two lanes of the eastbound 401 were shut down for several hours, backing up traffic.

All lanes reopened late in the morning.

Police said it was too early in their investigation to comment on any possible charges.

With reporting by Alexandra Pinto