The National Energy Board said it was responding to a release of crude oil near Sarnia, Ontario. The NEB said it wasn't able to determine the volume of the release though absorbent booms were deployed in the river as a precaution.
NEB said the spill was situated between two oil terminals in Ontario along a right-of-way for pipelines shared by Plains Midstream Canada, Imperial Oil and Enbridge Pipelines Inc.
The NEB said all pipelines associated with the area were closed to prevent an additional release of oil. The agency said an excavation team would be required to determine the source of the leak.
"There is no immediate safety concern for local residents and precautions are being taken to ensure continued public safety," NEB said Tuesday. "There is no indication that any oil has entered the St. Clair River."
NEB said its emergency response personnel were working with the oil companies, first responders and the Ontario Ministry of Environment to address the incident.
None of the oil companies involved in the incident published public comments about the release.