Sarnia residents may notice high flaring at the local Imperial refinery Wednesday evening.
Imperial says an equipment outage has caused the flaring, as well as additional steam venting.
"Safety is our top priority as we work to bring our equipment back online and return the plant to normal operations," the company says in a statement.
Imperial says it is monitoring air conditions, as is a third-party company, to ensure safety.
Earlier Wednesday morning, Imperial restarted equipment at the refinery following planned maintenance. The company says the outage is a separate issue.
The Ministry of Environment and Climate Change has been notified of the situation.
No further information has been released at this time.