Environmental activists and Native American tribes attempting to permanently shut down the Dakota Access Pipeline scored a major legal victory on Tuesday as the Supreme Court declined to hear an appeal from the pipeline’s developers. That rejection means the court will let stand a lower court ruling which called for a more thorough environmental review and rejected an important federal permit granted to Energy Transfer Partners, the pipeline’s developer.

A July 2020 district court ruling determined a federal permit granted to Energy Transfer by the Army Corps of Engineers was in violation of the National Environmental Policy Act. Energy Transfer asked the Supreme Court to reverse that decision, claiming the lower court’s ruling would put the pipeline “at a significant risk of being shut down,” according to the Associated Press.

Though environmentalist groups welcomed the Supreme Court’s decision Tuesday, it renewed calls by some to force the pipeline to halt operations until the new environmental review is complete.

“The litigation concerning the pipeline is over, but the fight continues,” Earthjustice attorney Jan Hasselman said in a statement. “We call on the administration to close the pipeline until a full safety and environmental review is complete. DAPL never should have been authorized in the first place, and this administration is failing to address the persistent illegality of this pipeline.”

Activists and members of the Standing Rock Sioux Tribe have spoken out against the roughly 1,134-mile pipeline intended to transport crude from the Bakken oil fields in northwest North Dakota. The heart of the issue revolves around a 2-mile segment of the pipeline that runs underneath Lake Oahe, crossing about half-mile north of the Standing Rock reservation. Opponents of the project worry a leak or spill (which has happened before) could seep into the Missouri River, ultimately contaminating the tribes’ primary water source. Members of the Standing Rock Sioux Tribe claim the pipeline could damage or destroy nearby sacred burial sites.

The lower court’s 2020 ruling against the pipeline came in response to a 2016 lawsuit filed by the Standing Rock Sioux Tribe amid an outpouring of activism against the pipeline. Though construction efforts were temporarily frozen under the Obama administration, that abruptly changed in the first weeks of the Trump presidency, thanks to an executive memorandum aimed at accelerating the pipeline’s construction.