LANSING — Public comment for the state’s environmental review of the Line 5 tunnel project ends on Friday, Aug. 29 — and one Michigan expert is raising concerns about the safety of the effort.
Brian O’Mara, a geological engineer with decades in the tunneling industry, says he’s concerned with some of the data he’s seen regarding the rock quality of the Great Lakes bottom lands.
The results are found in a 2020 study from WSP, an engineering consulting company who was contracted by Enbridge.
O’Mara says that over a quarter of those samples fell into the “very poor” category, closer to gravel than to stable rock.
“You could either have a disaster while they’re constructing the tunnel because of a sinkhole that develops under the existing pipeline, or you can have a fire and explosion that leads to a loss of secondary containment of the pipeline and a release of that oil and gas out into the Straits of Mackinac,” O’Mara said.
Enbridge spokesperson Ryan Duffy pushed back on O’Mara’s claims, saying in a statement that the tunnel project would “effectively eliminate” the risk of a safety incident.
“These issues on ground conditions were thoroughly reviewed by the Michigan Public Service Commission in its approval process,” Duffy said. “Tunneling experts retained by the Mackinac Straits Corridor Authority have confirmed the ground conditions are adequate for tunneling.”
The Michigan Public Service Commission didn’t comment on the claims due to a lawsuit challenging their 2023 approval of the project.
The Mackinac Straits Corridor Authority did not respond to a request for comment.
Duffy also pointed to a 2017 report commissioned by the state which concluded that “good rock conditions and minimal water inflow are anticipated at the Straits and no adverse geotechnical conditions are known to exist which would negate tunneling as an option.”
The Department of Environment, Great Lakes and Energy says their reviews do not concern these factors or tunneling operations.