Largest onshore crude pipeline spill in nine years in rural Kansas creek raises questions about operation of Keystone pipeline by Canada company TC Energy.
More than two dozen Democrats in Congress are demanding the White House pause construction on the Line 3 project and carry out new environmental studies.
Critics say officials are ignoring the potential threat to wildlife and the environment.
The congressman urged state officials to think about climate change, pollution and Native American rights.
They fear the pipeline will jeopardize drinking water and sacred sites.
Standing Rock Sioux Reservation members are running 2000 miles to deliver a petition to lawmakers, asking them to stop an oil pipeline that risks polluting their ancestral lands.