A breach at the Poplar pipeline in eastern Montana spilled 50,000 gallons of oil Saturday morning into the Yellowstone River.
Bridger Pipeline, the operator of the pipeline, confirmed that between 300 to 1,200 barrels of oil was released from the pipeline.
No injuries were reported.
Government officials said there is no threat to public health or safety.
Wyoming-based Bridger shut the Poplar pipeline down shortly before 11 am. Saturday after the spill was detected.
An unknown amount of oil reportedly reached the water although the river was frozen at the time of the spill.
A spokesman for Montana governor Steve Bullock said the frozen water could reduce the impact of the release.
“We think it was caught pretty quick, and it was shut down,” the governor’s spokesman told the AP.
A Bridger spokesman said the company is working quickly to minimize the environmental impact of the spill.
“We’re going to do whatever we have to do in order to clean this spill up,” Bridger told KULR8.
The Environmental Protection Agency and the Montana Department of Environmental Quality are investigating the incident.
The cause and the exact size of the spill has not been determined yet.