A 29-year-old man is in critical condition after firefighters, police, and paramedics were called about a possible drowning at Canatara Beach on Sunday.
Sarnia Fire Rescue said crews were called to the beach at around 6 p.m.
When they arrived, they found an unresponsive person on the shore.
Firefighters immediately started CPR and continued to do so until the person was transported to Bluewater Health by emergency medical services.
Point Edward Fire & Rescue also sent its marine unit to assist with the call.
On Monday, Sarnia police said the man remains in intensive care.
On Tuesday, Sarnia fire confirmed that one of its off duty firefighters pulled the man from the water and started CPR.