A small fire has been reported at the Shell plant in Corunna.
A Code 8 was issued for the plant at 150 St. Clair Parkway at around 8:42 p.m. on Thursday.
The Aamjiwnaang Notification System reported a "small fire in process 2".
The all-clear was issued just before 10:30 p.m.
The company said as a result of the upset, elevated flaring is possible. They say regular air monitoring is occurring and safety precautions and protocols are being followed.