Terrance McGill, vice president of natural gas operations at Enbridge, said the company was investigating reports of a gas leak about 60 miles off the Louisiana coast in the Gulf of Mexico.
"If a leak is confirmed as a result of the diving activities, we will immediately begin repairs," he said in a statement. "We do not anticipate any potential business interruption to be material."
McGill said a dive team was dispatched to investigate following reports of a 3-foot-diameter patch of bubbles near the pipeline. Stingray can carry as much as 560 million cubic feet of natural gas per day.
The leak comes amid debates over plans by Enbridge to build the Northern Gateway pipeline from Alberta tar sands fields to the west coast of Canada.
The Canadian government complained "radicals" were behind plans to thwart the project that could ultimately feed energy-hungry Asia.
Critics complain Alberta crude is the dirtiest type of oil on Earth. Enbridge is still working to clean up a spill of Alberta crude from a pipeline that ruptured in southern Michigan in 2010.
The U.S. Department of Transportation's Pipeline and Hazardous Materials Safety Administration had no public comment available on the Enbridge incident in the Gulf of Mexico.