One person is dead in a three vehicle crash on the 401 westbound at Whites Road, in the collectors.
OPP say all lanes of the collectors needed to be closed for the investigation and the cleanup.
"We're dealing with a considerable debris field," says Acting OPP Sgt Dan Hunter.
As for what happened, at around 10 o'clock on Friday morning, a vehicle stalled in the second lane of four. That's when the SUV was struck from behind by another vehicle that was travelling at highway speed. The SUV then burst into flames.
Two other peope have been sent to hospital with minor injuries.
Hunter couldn't say whether or not charges would be laid, but added the investigation was just starting.
Jennifer Williams