FARGO, N.D. (AP) — A federal judge has ordered the Dakota Access pipeline shut down pending a more thorough environmental review. The ruling Monday hands a victory to the Standing Rock Sioux Tribe three years after the pipeline first began carrying oil following months of protests.

U.S. District Judge James Boasberg wrote that he was “mindful of the disruption” that shutting down the pipeline would cause, but that it must be done within 30 days. Tribal Chairman Mike Faith called it a historic day for the Standing Rock Sioux. The tribe worries an oil spill could pollute the Missouri River. Texas-based Energy Transfer has insisted its pipeline is safe.