The Suncor refinery responded an incident involving the St. Clair River on Wednesday night.
An alert was issued just after 7:30 p.m., reporting a spill to the river. The notification added that the spill was contained at the time, and that the suspected chemical involved was hydrocarbon.
Community members may notice increased activity and an odour coming from the St. Clair River as a result.
If community action is required, instructions will be issued by the municipality.