An ExxonMobile pipeline spilled as much as 42,000 gallons (1,000 barrels)  of crude oil into the Yellowstone River near Billings, Montana on Saturday, Jul 2. No cause has yet been identified for the oil spill. The Yellowstone River is a tributary to the Missouri river, leading to fears that the oil could end up entering the Missouri river.

According to ExxonMobile Pipeline Company, the pipeline pumps were turned off within seven minutes after the pressure loss was detected to minimize the amount of oil released into the river. Oil has been found as far as five miles downriver of the spill, and pipeline executives on Sunday said that the oil was confined to a ten mile section of the river.

About 140 local residents were evacuated, but were allowed to return home on early Sunday.

The Billings Gazette reports that local farmers have spotted oil in their fields, carried from the Yellowstone river by flood waters and that the smell of oil was pervasive in several areas.

The pipelines company promised to clean-up the oil spill completely. In a statement on their website, ExxonMobil Pipeline company said: