One person was left in critical condition after four vehicles collided north of Toronto on Highway 50 near Langstaff Road.
The collision occurred shortly before 3 p.m. and an Ornge air ambulance was called to transport one patient who may have life-threatening injuries, police said.
The 28-year-old man has serious injuries to his leg and was to be taken to St. Michael's Hospital, an Ornge spokesperson said.
Two others were taken to a trauma centre by ambulance and four others were taken to a local hospital, police said.
Police have closed Highway 50 between Zenway Boulevard and Rutherford Road as they investigate the collision.
The highway will remain closed for several more hours, police said.
