Enbridge said about 750 barrels of oil spilled from its so-called Line 37 pipeline. The company said oil spilled into a small creak and unnamed lake about 44 miles southwest of Fort McMurray.
"No injuries or evacuations have occurred," the company said in a statement Sunday. "No potable water wells are affected by the release. No air-quality issues have been identified."
Line 37 is described as an 11-mile pipeline that connects to a larger system tied to oil sands production in Alberta. The type of crude oil extracted from Alberta is heavier than water, making it more difficult to remove from rivers and streams.
The company said it shut the pipeline down remotely within 10 minutes of spill detection. The site of the release is accessible only by helicopter and all-terrain vehicles.
"We are still investigating the cause; however, we believe that unusually heavy rains in the area may have resulted in ground movement on the right-of way that may have impacted the pipeline," the company said in a statement.
Parts of Alberta are in a state of emergency because of heavy flooding. Enbridge said its corporate offices were closed Monday because of the weather.