Many pipelines carrying oil and other hazardous materials have been found to be at risk of failure throughout Montana and Wyoming.
The susceptible sites include seven major river crossings as well as hundreds of smaller crossings. Federal inspectors and state officials took note after an Exxon Mobil pipeline broke in July, spilling about 1,000 barrels of crude oil into the Yellowstone River.
Governor Matt Mead says the state is working with companies to figure out where the problems are.
"We have not addressed that in a regulatory way. Our approach so far has been working with the companies that have pipelines and asking them what the status of them is. So it has been a voluntary effort in terms of knowing what the pipelines…where they are and what the conditions are."
Most of the pipelines are owned by Exxon Mobil, CHS and ConocoPhillips. Many were installed decades ago and have since been exposed through erosion.
Some repairs are already underway. If they aren’t completed by spring, companies will face enforcement actions. .