Lambton OPP, fire and EMS responded to a crash with serious injuries south of Watford just before noon on Friday.
The OPP says a vehicle traveling south on Nauvoo Rd. suddenly veered off the road and rolled over in the east ditch, just north of LaSalle Line.
Two people were transported to hospital by ambulance with life threatening injuries.
The OPP's Technical Traffic Collision Investigators were dispatched to the scene.
Nauvoo Road between Lasalle Line and Churchill Line was expected to be closed until sometime Friday night.
Anyone with information is asked to call OPP.
