Almost 70 people - most of them children - were sent to hospital after two school buses caught fire on a highway near St-Eustache on Tuesday morning.

The fire started after an accident involving the two buses and another vehicle on Highway 640.

A Toyota Corolla on the highway slowed down and a school bus travelling behind it rear-ended the car, according to the Surete du Quebec, who said a 911 call was placed at 10 a.m.

A second school bus then collided with the first bus. A fire erupted that severely damaged both buses.

"We were inside and we heard the boom. We saw the smoke. We ran outside. We saw it was two busses," said Marios Kafrouni who works at a nearby car dealership. "We ran outside to rescue the poor kids. We got bottled water and took them to (the dealership). After that, we heard the boom. It was the tire I guess."

Police said the children on board the buses managed to get out safely but 69 people were taken to hospital. Officials said the injuries were minor. 

Some of the children were taken into the car dealership following the accident.

The buses were carrying 83 children between the ages of five and 12 to a day camp in Brossard, a spokesman for the city told The Canadian Press.

The drivers of the two buses and car were not injured. 

The 640 West was closed to traffic in the area.

St-Eustache hospital spokesperson Myriam Sabourin said they issued a code orange alert, meaning extra staff rushed to the health facility to help, including emergency room workers and teams from other regions.