This Groundwork op-ed first published in the Detroit Free Press.

The oil company Enbridge wants to move its Line 5 oil pipeline from the Straits of Mackinac into a tunnel beneath the lake, and the Michigan Public Service Commission recently signed off on this plan, issuing Enbridge a site permit. Encasing Line 5 in concrete and burying it deep beneath the Great Lakes may sound like a reasonable idea, given that Line 5 currently lies exposed on the bottomlands of the Straits of Mackinac, just one anchor strike away from an environmental disaster.

Believe it or not, that decision could actually make things worse.

Transporting propane and crude oil involves highly hazardous, volatile substances that always bear an inherent risk of explosion. That’s just one reason why four tribes and numerous Great Lakes advocates are contesting the commission’s decision in the Michigan Court of Appeals. In their testimony to the commission, highly qualified experts spoke out safety concerns on behalf of the Bay Mills Indian Community against Enbridge’s tunnel design. Commissioners should have listened. 

We need Line 5 out of the Great Lakes all together — not in a tunnel, not on the lake bottom. This permit should be revoked, and President Joe Biden should revoke the presidential permit that has allowed Line 5 to operate since 1953.

One geological engineer and tunnel expert, Brian O’Mara, the founder and Principal of Agate Harbor Advisors LLC, identified three potential explosion scenarios for the proposed tunnel. The first could happen during the tunneling process, when highly explosive dissolved methane could enter the tunnel. After construction, due to the immense pressure under the Straits, groundwater containing methane could enter the tunnel. (Enbridge has already found dissolved methane in 20% of groundwater samples taken during geologic surveys.) Finally, an explosion could be caused if the crude oil itself leaked from Line 5 itself.

In any of these scenarios, O’Mara testified, a single spark would cause the pipeline to detonate like a bomb. O’Mara noted, chillingly, that “the spark generated between a person’s finger and doorknob after walking across carpeting on a dry day produces significantly more energy than required to ignite a methane/air explosion.” This becomes even more worrisome when you consider that Enbridge is still exploring ways to include other third-party utilities in the tunnel, like proposed fiber optics facilities and others.  

Another pipeline safety technical expert, Richard Kuprewicz, president of Accufacts Inc., pointed out that the design is also “unusual and especially risky” because it allows the pipeline to move in such a way that it will create abnormal loading on the seams where the segments of pipe are welded together, or adjacent areas that may have been weakened or stressed by the heat of the welding process. Ultimately, he testified, this could “result in full bore pipeline rupture.” 

If you think our regulators won’t let this flawed design proceed, you’re sorely mistaken. No one agency has complete oversight over its approval — not Michigan’s Department of Environment, Great Lakes and Energy, nor the U.S. Army Corps of Engineers. Even the federal administrator charged with pipeline oversight, the Pipeline and Hazardous Material Safety Administration does not have authority to avert disaster. According to Kuprewicz, “Compliance with PHMSA regulations does not assure that a pipeline will not fail; if that were true, we would not see pipeline rupture failures happening across the country, but we do.” 

And that’s the larger problem with the entire tunnel approval process — it is happening piecemeal, with no single agency held to account for the full impact of the project.

And no, we can’t trust Enbridge to avert a spill using the best available technology. For example,  O’Mara stated, “Enbridge has no active fire suppression system for the Line 5 tunnel and relies only on passive fire-resistant concrete and stopping ventilation.” He went on to testify that the plan to seal both ends of the tunnel would likely make a potential fire burn hotter. 

Let’s review the company’s history, starting with the catastrophic 1991 Line 3 rupture in Grand Rapids, Minnesota, when Enbridge adopted its so-called “10 minute rule” — if operators can’t figure out why monitors indicate a problem, they shut down the pipeline after 10 minutes. However, experience tells us that Enbridge doesn’t play by its own rules. Take, for example, the $1.2 billion dollar Line 6B spill in Marshall, Michigan, in 2010. Operators were alerted to a problem, yet allowed the pipeline to continue to run for 17 more hours, as thick oil blanketed 40 miles of the Kalamazoo River.

There’s more. In 2021, Enbridge made maritime navigational history when its own contractor managed to actually hit the iconic Mackinac Bridge. The company has failed to prevent three known anchor strikes in recent years, plus one instance where its contractor lost a 15,000-pound anchor in the Straits. Enbridge also has failed to prevent 35 oil spills, releasing over a million gallons of fuel from Line 5 during its 70-year life span.

In short, this Canadian company cannot be trusted. 

So, now what? The Public Service Commission has approved the tunnel permit, but the appeal process still looms long. In the meantime, Line 5 will keep pumping crude oil through aging pipes strung atop the bottomlands of the Mackinac Straits, making Enbridge an estimated $1.8 million per day. Make no mistake, Enbridge will continue to run this pipeline — and pitch this tunnel pipe dream at all costs.

Biden should revoke the Line 5 presidential permit now. That would shutdown the existing 645-mile-long pipeline, and eliminate any future debate about the oil tunnel once and for all.

Ashley Rudzinski, Climate & Environment Program Director
ashley.rudzinski@groundworkcenter.org