A coalition of environmental groups is challenging the federal permit for the Keystone XL oil pipeline in court because they say additional environmental scrutiny is needed.
The Sierra Club joined with several other environmental groups to file the federal lawsuit Thursday in Montana.
Other groups include Northern Plains Resource Council, Bold Alliance, Center for Biological Diversity; Friends of the Earth and the Natural Resources Defense Council.
"The Bold Alliance is proud to stand with the millions of people our organizations represent in this challenge to the State Department’s flawed approval process for the KXL pipeline.," said Ken Winston, the legal counsel for Bold Alliance.
"We stand for the rule of law and protection of the air, the lifegiving water and land that sustains us. We stand against eminent domain for private gain. KXL still has no legal route through Nebraska; TransCanada has the burden to prove their proposed route is in the public interest."
The proposed pipeline that TransCanada wants to build would carry crude oil through Montana, South Dakota and Nebraska where it would connect with an existing Keystone pipeline network that moves crude to Texas Gulf Coast refineries.
The environmental groups say the initial environmental review completed in 2014 is inadequate and outdated.
The U.S. State Department issued a permit for the project earlier this month, although Nebraska regulators still must review the proposed route there. Officials with the State Department and TransCanada declined to comment on the lawsuit.