Seven people were sent to hospital following two crashes on Highway 115 near Pontypool on Sunday night
Whitby OPP say around 6:45 p.m. a car first rolled in the southbound lanes just south of Boundary Road. Moments later three other vehicles collided.
Police say the driver of the rolled car was air lifted to a trauma centre and a passenger taken by ambulance to hospital, both with possible life-altering injuries.
Paramedics transported three other passengers with non-life threatening injuries.
Two passengers in the second collision were transported with minor injuries.
All southbound lanes were closed at Boundary Road until about 2 a.m. Monday.
OPP are appealing to witnesses as they continue to investigate.