A Montana pipeline burst sent as much as 50,400 gallons of oil gushing into the Yellowstone River, prompting the governor to declare a state of emergency.
Residents in nearby cities were told not to drink the tap water, which some said smelled like diesel.
The massive oil spill happened when the 12-inch pipeline, which crosses the Yellowstone River, ruptured Saturday about 5 miles upstream from Glendive, Montana's Department of Environmental Quality said. The Bridger Pipeline company shut down the pipeline.
Glendive City Council member Gerald Reichert was among the residents who noticed a disturbing odor in the drinking water.
"Suddenly at our house there was a definite smell. It was a diesel smell," Reichert told the Grand Forks Herald.
Montana Gov. Steve Bullock announced a state of emergency for Dawson and Richland counties.
And while officials wait for results from water sample testing, they're advising residents to use bottled water for drinking and cooking.
A host of agencies have responded to the oil spill, including the Environmental Protection Agency and the Department of Health and Human Services.
Adding to the problems, the weather: the Yellowstone River is partially frozen, making it difficult to clean up the mess.
This isn't the first major oil spill into the Yellowstone River -- the longest undammed river in the United States.
In 2011, up to 42,000 gallons poured out of a ruptured Exxon Mobil pipeline.
