The Wisconsin Department of Natural Resources has ordered Enbridge to stop construction on a temporary bypass for its Line 5 pipeline after the company began the work without state approval following a major spill in Iron County. The Aug. 25 spill near Saxon released about 1.3 million gallons of natural gas liquids, making it the largest spill in Enbridge’s history, according to the DNR. The release occurred when an unoccupied truck struck a valve during construction work. After the incident, Enbridge began working to bypass the damaged valve so Line 5 could resume transporting Canadian oil and gas. On Wednesday, the DNR issued the company a notice of noncompliance, saying the bypass work was proceeding without permits that could be required from the state, Iron County and federal agencies. DNR Secretary Karen Hyun said the agency had warned Enbridge three times that it could not begin the work without authorization. The notice says the construction includes placing mats in wetlands near Spoon Creek, a navigable waterway regulated under state law. Hyun said she was “deeply concerned and incredibly frustrated” by Enbridge’s actions and by what she described as additional environmental discharges connected to the company’s recent work. She specifically cited volatile organic compounds, pollutants that can pose risks to human health and the environment. “Enbridge has continued to add to the growing list of environmental concerns and violations,” Hyun wrote, saying the company’s actions showed disregard for environmental protections, public health and the DNR’s legal authority. Enbridge spokesperson Juli Kellner said the company is working around the clock both to clean up and control the spill site and to complete the temporary bypass. She said the work is intended to help restore service and address energy supply disruptions. “Line 5 is critical infrastructure delivering energy to millions of people in the Midwest and Great Lakes regions,” Kellner said. She added that Enbridge is working with the DNR on permitting and separately on environmental conditions at the spill site. The spill and the bypass dispute have intensified opposition to the Line 5 reroute, which would move the pipeline off the Bad River Band’s reservation in northern Wisconsin. The project has faced challenges to state and federal permits, as well as opposition from tribal members, environmental groups and elected officials in Wisconsin and Michigan. Rob Lee, an attorney with Midwest Environmental Advocates who has challenged Enbridge’s Line 5 permits, said the company cannot place the goal of returning the pipeline to service above state environmental law. “Enbridge knew it needed authorization before it started this work. The DNR told the company that repeatedly. Enbridge went ahead anyway,” Lee said. He said the company had moved earth, crossed waterways and disturbed wetlands without permits, and urged the DNR to consider revoking permits for the reroute if violations continue.