Exxon Mobil Silvertip Pipeline Oil Leak on the Yellowstone River

Section of Silvertip Pipeline

Exxon Mobil Corp.’s oil leak into the Yellowstone River could extend far beyond a 10-mile stretch of the waterway and the company has intensified its cleanup of tens of thousands of gallons of spilled crude.  Exxon Mobil has estimated that up to 1,000 barrels, or 42,000 gallons, of crude oil spilled Friday night before the flow from the damaged pipeline was stopped.  The 20-year-old Silvertip pipeline delivered 40,000 barrels a day to a refinery in Billings along a route that passes beneath the river.

The leak from the 12-inch pipeline caused the temporary evacuation of some area residents. Local officials have said that flooding has hampered the cleanup work, and that some of the leaked oil could reach the Missouri River, of which the Yellowstone is a tributary.

People near the area with acute hydrocarbon exposure are experiencing dizziness, nausea and trouble breathing. The Environmental Protection Agency is still taking air and water samples to determine the impacts.  The cause of the Montana spill has not yet been determined. Company and government officials have speculated that high waters in recent weeks may have scoured the river bottom and exposed the pipeline to debris that could have damaged the pipe.

The U.S. Department of Transportation, which oversees pipelines, notified Exxon Mobil in July 2010 of seven potential safety violations and other problems along the pipeline. Two of the warnings faulted the company for its emergency response and pipeline corrosion training. The company also was cited for “probable violations” in a February letter. Those included inadequate pipeline markers in a housing development, a section of pipeline over a ditch covered with potentially damaging material and debris, vegetation in a housing area that covered a portion of line and prevented aerial inspections, and a line over a canal not properly protected against corrosion.

More than 280 people were involved in the response and cleanup and more than 9 miles of absorbent booms are being deployed. (Wash Post, 7/4/2011, NY Post, 7/4/2011))