GLENDIVE, Mont. — Sonar indicates part of an underground pipeline that spilled almost 40,000 gallons of oil into Montana's Yellowstone River and fouled a local water supply is exposed on the riverbed.
The pipeline is exposed for about 50 feet near where the breach occurred Jan. 17, according to a news release from public agencies involved with the response.
The pipeline had been buried at least 8 feet under the riverbed, and the depth was last confirmed in September 2011.
The cause of the spill remains under investigation. It prompted a five-day shutdown of drinking water services for 6,000 people in the city of Glendive after oil got into a treatment plant.
Prior accidents, including a 2011 Exxon Mobil pipeline spill on the Yellowstone near Billings, have demonstrated that pipelines beneath bodies of water can quickly become exposed by floodwaters or other natural forces.
The 193-mile Poplar Pipeline delivers crude from the Bakken oil patch of North Dakota and Montana to a terminal in Baker, Montana, about 55 miles south of Glendive. It was built in the 1950s and has a capacity of 42,000 barrels of oil a day.