Six people were injured after two vehicles collided on Highway 40 between Chatham and Wallaceburg.
The incident happened just before 4 p.m. on Wednesday, resulting in Elgin County Ontario Provincial Police (OPP) closing off the road for several hours.
An 80-year-old passenger from Chatham-Kent (CK) suffered serious, life-threatening injuries. The driver, an 87-year-old from CK, suffered serious but non-life-threatening injuries. Both were taken to hospital for treatment.
The driver of the other vehicle, a 67-year-old from CK, and three passengers, aged 41, 19, and 14, suffered minor injuries.
The investigation into the cause of the accident is ongoing.