Photograph by Matthew Brown, Associated Press

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Cleanup workers cut holes into the ice on the Yellowstone River near Crane, Montana, Monday after a pipeline spill that released up to 50,000 gallons of crude.

Photograph by Matthew Brown, Associated Press

Oil Spills Into Yellowstone River, Possibly Polluting Drinking Water

The spill, area's second in four years, won't affect the upstream Yellowstone National Park.

The scenic Yellowstone River has suffered its second sizable oil spill in four years, prompting truckloads of drinking water to be shipped into the eastern Montana city of Glendive. The latest spill is not expected to affect Yellowstone National Park, about 350 miles upstream.

Some oil from the weekend spill got into a water supply intake along the river that serves about 6,000 people in Glendive, according to preliminary tests at the city's water treatment plant. The sample showed elevated levels of volatile organic compounds, predominantly benzene, that would explain the odor in tap water, officials at the plant said. The potential health risks are uncertain until further testing is complete, they said.

"There will be more sampling from more points along the system," says Bill Salvin,  spokesperson for Wyoming-based Bridger Pipeline, a subsidiary of True companies that is responsible for the spill. In the meantime, he says, "we are bringing in water to the city of Glendive" and will continue to do so until the weekend.

A breach along the Poplar Pipeline caused a spill of up to 50,000 gallons of oil produced in the Bakken shale fields of Montana and North Dakota, Bridger Pipeline announced Saturday.

"There's no way we're going to see an impact on the park," Salvin says of Yellowstone National Park. Though the park is located southwest of the spill, Salvin says the 692-mile-long Yellowstone River flows northward from the park through Montana into North Dakota. (Take the quiz: "What You Don't Know About Oil Spills.")

Another spill into Yellowstone River occurred 235 miles southwest of Glendive in July 2011, when an ExxonMobil pipeline broke near Laurel, Montana, and released 63,000 gallons of oil that washed up along an 85-mile stretch of riverbank.

After the latest spill, initial water tests showed no evidence of oil, but residents soon complained that their tap water had an unusual odor. An advisory against using it was issued late Monday by the city's treatment plant. (See related story: "Q&A: What Federal Ruling Against BP Means for Oil Drilling's Future.")

Bridger Pipeline said the break in the 12-inch steel pipe happened in an area about five miles upstream of Glendive, an agricultural community in east-central Montana near the North Dakota border. An Environmental Protection Agency official said an oil sheen was detected near Sidney, about 60 miles downstream.

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A section of the Yellowstone River appears in 1997, not far from where a 2011 spill would leak 63,000 gallons of oil into the water.

"This is a significant spill," the EPA said in a statement Monday night, adding the oil "threatens downstream water users, including drinking water supplies, agricultural uses, and wildlife." The EPA said it was working with Bridger, local and state officials as well as the U.S. Fish and Wildlife Service and the U.S. Department of Transportation to contain the spill. It said responders are placing containment structures across the Yellowstone River at Sidney, Montana, about 30 miles downstream of the spill.

The river is partially frozen, complicating the cleanup effort. "These are horrible working conditions to try to recover oil," Paul Peronard, the EPA's on-scene coordinator, told CBS News, as crews chopped holes into the ice to clean up the crude. "Normally you at least see it, but you can't see it, you can't smell it, " he said. "We're going to have to hunt and peck through ice to get it out." (See related story: "What Happens When Oil Spills in the Arctic?")

The Poplar Pipeline, which runs from Canada to Baker, Montana, carries crude oil from the Bakken oil fields. It remained closed Monday as crews worked to pump out any oil left in the section where the breach occurred. It cannot be restarted until it receives approval from the U.S. Department of Transportation's Pipeline and Hazardous Materials Safety Administration, which dispatched inspectors to the area. (See related story: "Oil Spill Spotlights Keystone XL Issue: Is Canadian Crude Worse?")

For its 2011 spill into Yellowstone River, ExxonMobil faces state and federal fines of up to $3.4 million as officials seek damages for injuries to birds, fish, and other natural resources. The company has said it spent $135 million on cleanup efforts.

The EPA says 14,000 oil spills are reported each year, but it says many are small enough to be cleaned up by the company that caused them.

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The story is part of a special series that explores energy issues. For more, visit The Great Energy Challenge.