The eastbound lanes of Highway 401 near Grafton were shut down for several hours on Monday afternoon following a crash.
It happened around 2 p.m. jut east of Lyle Street, and involved two transport trucks.
Witnesses say one of the trucks hauling bottled water was going slowly with its four- way lights on when it was rear-ended by another truck.
It then caused a small chain-reaction of collisions. One person was treated for minor injuries.
The crash caused oil and debris to spill across the highway.
One of the drivers suffered minor injuries.
No word on yet on if charges are pending.