Shortly before 2 p.m., Quebec provincial police received a call from a driver who said a vehicle was spilling oil on Highway 15 North, near the 117 exit.
Police tracked down the flatbed truck, which was leaking oil from one of the five transformers it was carrying.
Workers used a back-hoe to remove the leaking transformer.
Environment Quebec said it recovered at least 200 litres of the oil.
Officials said there is no danger to the public, but they will have to wait for test results to determine the exact contents of the oil.