Increased flaring and noise may be noticeable from Shell's Sarnia Manufacturing Centre in Corunna Thursday afternoon.
The company reported a unit upset at the site at 12:50 p.m.
Shell said safety precautions and standard regulatory protocols were being followed as crews work to return the unit to service.
The company said the Spills Action Centre (SAC) and Community Awareness Emergency Response (CAER) would be notified as needed.