Imperial Oil emergency personnel were called to put out a minor fire in Area 2 at the Sarnia refinery Tuesday afternoon shortly before 1:30 p.m.
A Chemical Valley Coordinating Organization (CEVCO) notification was issued. Imperial says no injuries were reported and refinery operations continued without disruption.
Air monitoring in the vicinity and downwind of the incident was conducted and an all clear was issued at 2:01 p.m.
The Environment Ministry was notified and the exact cause is being investigated by Imperial Oil.