Motorists were advised to avoid the area of London Line and Mandaumin Road after a tanker and a transport truck collided at the intersection Tuesday.
Sarnia Police, Sarnia Fire and Rescue and Lambton EMS responded to the scene at around 12:20 p.m.
The tanker entered the ditch, and the transport landed onto its side.
Cst. John Sottosanti said there were long traffic backups reported in the area.
He said both drivers were transported to hospital with serious but non-life threatening injuries.
The roadway was expected to be closed for several hours, and detours were in place.