Under the Straits of Mackinac, a single 30-inch pipe splits into two 20-inch lines. That is Enbridge’s Line 5 where it crosses the water, a stretch of roughly 3.7 miles lying on the lakebed at depths of up to about 240 feet, according to the U.S. Army Corps of Engineers.
The line itself is much longer. It carries light crude oil and natural gas liquids 645 miles from Superior, Wisconsin to Sarnia, Ontario. Enbridge applied to state and federal regulators in April 2020 to replace the aging crossing, and environmental groups objected from the start, citing possible violations of the Michigan Environmental Protection Act.
Permits granted, then questioned
The Michigan Department of Environment, Great Lakes, and Energy and the state Department of Natural Resources approved two environmental permits for a replacement tunnel in July 2026, after environmental assessments and public hearings. Less than two weeks later, the Michigan Supreme Court ruled 6-1 that state regulators had not fully weighed the project’s environmental effects. The Michigan Public Service Commission now has to reevaluate Enbridge’s proposal before construction can proceed.
The federal side moved the other way. On a Wednesday in August, the Army Corps issued the permit for the 3.6-mile tunnel, the last federal approval the Canadian company needed. “This has been a very carefully weighed decision,” said Lt. Col. Donald K. Lew, the Detroit District Commander.
Whitney Gravelle, president of the Bay Mills Indian Community, welcomed the court’s decision. “The Straits of Mackinac are not simply a route for an oil pipeline to be abused,” she said. “They are sacred waters, the heart of creation for Anishinaabe people, and a source of life for millions.”
Washington against Lansing
Politics hardened in September. Writing in Forbes, Daniel Markind reported that EPA Administrator Lee Zeldin voiced support on September 26 for the tunnel at an energy roundtable with Michigan oil and gas industry figures. His remarks followed Governor Gretchen Whitmer’s announcement that state regulators would reconsider a key state permit. Whitmer has called the line “a ticking time bomb in the heart of the Great Lakes.”
Markind also pointed to the stakes of a shutdown, which he said could hit natural gas availability in Michigan and jet fuel supplies to Detroit Wayne County airport and Toronto’s Lester Pearson. He noted a separate Line 5 problem in Wisconsin. On August 26, a flatbed truck improperly entered an evacuation site in Iron County, and about 1.3 million gallons of natural gas spilled a few miles from the Bad River Band’s reservation. The tribe and others asked Governor Tony Evers to declare an emergency.
Sources
- Line 5 Pipeline Remains Buffeted On All Sides (Forbes, Daniel Markind)
- US Army Corps of Engineers approves federal permit for Line 5 tunnel in Straits of Mackinac (ClickOnDetroit)
