A breached oil pipeline in Montana has spilled as many as 50,000 gallons of crude oil in and around the Yellowstone River, according to the state. Bridger Pipeline LLC has yet to determine the cause, but has claimed the public is in no immediate danger.

Cleanup crews were at work on Monday to address the mess, which emanated from a break in the Poplar Pipeline system about 9 miles upstream from Glendive in eastern Montana.

Bridger Pipeline said the rupture in the 12-inch steel pipe occurred early Saturday and lasted for one hour, dispensing no more than 1,200 barrels, or about 50,000 gallons, of crude oil.

Oil has been reported as far as 25 miles downstream from Glendive, according to company spokesman Bill Salvin. Some of the crude is trapped under ice.

"Oil has made it into the river," Salvin said, according to AP. "We do not know how much at this point."

While Bridger has claimed no immediate danger to the public, others are not so sure.