Police and ambulances were on the scene early Sunday after a major collision on Highway 15 North in Laval, near the intersection of de la Concorde Boulevard.
All lanes on the northbound side of the highway were closed until around 1 p.m. and a detour was set up on the service route near Cartier Street, according to provincial police.
All the lanes have since been reopened.
According to initial investigations by provincial police, one vehicle going south on the highway crossed the median and hit another vehicle, which then struck a third vehicle.
Three vehicles were involved in the crash — a tanker truck, and two small vehicles.
Three people were injured — one is seriously hurt, but police say the person's life is not in danger.
A small amount of gas leaked out of the truck's motor, and Urgence-Environnement was at the scene, police said.