Six minutes later, at the Exxon Mobil control room in Houston, workers used remote devices to shut down the pipeline’s pumps, reducing the flow. A valve near the refinery was closed, reopened, then closed again. Finally, 55 minutes after the pressure drop, the crucial valve on the other side of the river was closed.
Exxon Mobil estimates that in the interim as many as 42,000 gallons of crude oil spilled into the fast-flowing Yellowstone River, which is swollen with melted runoff from heavy winter snowfalls. The river, surging over its banks, snakes its way through Montana into North Dakota and empties into the Missouri River.
Suddenly, images familiar from last summer’s much bigger Gulf of Mexico spill are back: Workers mopping up oil with absorbent pads and laying plastic booms near shorelines. Soiled grasses and breeding grounds. Apologies from a big oil company. And an angry governor.
Montana Gov. Brian Schweitzer (D), who has a master’s degree in soil science, vowed to “stay on this like smell on a skunk until it’s cleaned up.” He added: “Exxon Mobil? They’re going to pay for it. I promise you this right now. Yellowstone is cleaned up when the state of Montana says it’s cleaned up, not some bureaucrat from Washington or the state of Texas.”
If Exxon’s estimate is correct, this spill would be just a fraction of 1 percent of the size of BP’s spill in the gulf last year. But the company said it had already spread nearly 20 miles, and others said it stretched twice that far. Schweitzer said flooding had carried the oil into eddies and wetlands that he called “the health and wealth of a river.”
Moreover, the spill raises questions far beyond the banks of the Yellowstone River: How can the nation’s 2.3 million miles of aging gas and hazardous-liquid pipelines be safely maintained? Exxon Mobil’s pipeline subsidiary alone has 8,000 miles of lines. Was there sufficient regulatory oversight? And how can a big company make sure that decisions in far-flung corners of its bureaucracy don’t end up causing a disaster?
Exxon now in spotlight
In the wake of the BP spill last year, Exxon Mobil executives said the 1989 Exxon Valdez tanker accident off the coast of Alaska taught them to control risks. Yet environmental groups said Exxon had failed to take measures that might have prevented the Yellowstone River spill.
The Transportation Department’s Pipeline and Hazardous Materials Safety Administration said it is looking into Exxon’s handling of the pipeline shutdown as well as its maintenance of the line’s other river crossings.
This past fall, officials from PHMSA had met with residents from the nearby town of Laurel because people there were worried that flooding from heavy snowmelt could erode the soil above the pipeline and expose it to damage from debris.