November 2017 The Nebraska Public Service Commission approved (3–2) the construction of the pipeline, albeit through an alternative route which is longer, but deemed to have the least environmental impact compared to two other routes that were considered. This proved to be a major setback for TransCanada since they would have "years of new review and legal challenges". TransCanada asked Nebraska to reconsider this decision and worked with Pipeline and Hazardous Materials Safety Administration (PHMSA) to determine the structural cause of a leak in South Dakota on November 21, 2017.