Gas Leak that Occurred on Enbridge's Line 5 Largest Oil Spill in Wisconsin

Thursday, September 10th, 2026 -- 9:00 AM

(Danielle Kaeding, Wisconsin Public Radio) A gas leak that occurred last month on Enbridge’s Line 5 is the largest oil and gas pipeline spill reported in Wisconsin in more than 50 years, according to a WPR review of federal data.

According to Danielle Kaeding with Wisconsin Public Radio, WPR analyzed hazardous liquid accident data submitted to the federal Pipeline and Hazardous Materials Safety Administration and data submitted by Enbridge and its predecessor Lakehead Pipe Line Company since 1970.

The data represents reporting for pipeline facilities used to transport hazardous liquids that include crude oil and natural gas liquids. Federal data indicates the Aug. 25 leak in Iron County that released 31,000 barrels, or 1.3 million gallons, of natural gas liquids is the company’s largest release reported to federal regulators.

Line 5 remains shut down. Enbridge has said the leak occurred after a subcontractor’s unoccupied flatbed truck rolled into an open excavation site for a Line 5 valve project, striking the pipeline and releasing mainly propane and butane into the atmosphere.

“The vast majority of the remaining two thousand barrels of liquid initially contained within the excavation site, have now also vaporized and dispersed. Today crews continue working on removing the remaining liquid from the trench,” said Enbridge spokesperson Juli Kellner in a statement.

Environmental groups are urging the Wisconsin Department of Natural Resources to do more in response to the spill, including demands for an independent investigation and revocation of permits for Enbridge’s $1 billion reroute of Line 5. Evan Feinauer, senior staff attorney for Clean Wisconsin, said he hopes the agency is actively exploring its options.

“The number of issues have now started to add up to a point where it’s problematic and concerning about what are other issues that are going to happen as they continue construction, both at the valve site where they had the leak and the other areas as well as on the reroute itself,” Feinauer told WPR. 

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