U.S. News » A judge has told federal officials to go back and review documents related to the disputed Keystone XL oil pipeline after environmentalists accused the government of withholding details on the project’s approval. U.S. District Judge Brian Morris in Montana said Wednesday that the government must provide any relevant documents by March 21 or explain why they should be withheld. The ruling came in a lawsuit from environmentalists seeking to stop the 1,179-mile pipeline from Canada’s oil sands region to U.S. refineries.