By Jim Bloch
Enbridge, the Alberta-based oil and gas transportation giant, is gearing up to construct a 3.9 mile tunnel under the Straits of Mackinac to relocate a portion of its controversial pipeline known as Line 5.
Using horizontal directional drilling machinery, the tunnel will be bored as many as 370 feet below the bottom of the Straits.
As part of the boring process, the company is planning to discharge billions of gallons of wastewater into Lake Michigan.
Organizations and tribes fighting the project are urging residents in the Great Lakes Basin to submit comments to the Michigan Department of Environment, Great Lakes and Energy opposing the permit that would allow the discharges.
EGLE’s public comment period closes June 30.
The permit would allow Enbridge to dump billions of gallons of wastewater – the equivalent of nine Olympic-sized pools a day, according to the environmental group FLOW Water Advocates – into the lake and to withdraw two million gallons of lake water per day.
The discharges would include chemical additives, chlorides, solids, and pollutants from heavy machinery, FLOW said.
The EGLE form on which to leave comments is available at: https://mienviro.michigan.gov/ncore/external/publicnotice/info/4645993131151403844/comments
“A proposed project like this requires several state and federal permits,” said FLOW on its website. “You may have already commented on a previous permit application, but it’s important to comment on this new permit application, too. This is likely our last chance to tell EGLE and Governor Whitmer to reject Enbridge’s dangerous and unnecessary tunnel project, and deny Enbridge permission to pollute the Great Lakes.”
In the process of excavating the tunnel beneath the lake bottom of the straits, Enbridge will remove 364,000 cubic yards of earth and rock, about 27,000 dump truck loads.
Line 5
The 645-mile Line 5 begins in Superior, Wisconsin and travels through the Upper Peninsula as a 36-inch pipe. It separates into two 20-inch pipes that rest on the silty lake bottom and on stanchions along the floor of Straits. The two pipes recombine as a 36-inch pipe for its journey through the Lower Peninsula – through Indian River, Lewiston, West Branch, Bay City and North Branch — to Marysville, where it dips under the St. Clair River enroute to Chemical Valley in Sarnia, Ontario.
Line 5 can handle as many as 540,000 barrels per day of light crude, light synthetic crude and natural gas liquids, which are refined into propane; there are 42 gallons in a barrel. The pipeline provides 65 percent of the UP’s propane and 55 percent of Michigan’s propane, according to the company.
The 73-year-old pipeline is nearly 25 years past its engineered life expectancy.
University of Michigan researcher Dave Schwab’s computer simulation in 2016 found that a worst-case spill in the Straits could pollute 720 miles of shoreline in Lake Michigan and Lake Huron, impacting Beaver Island, Bois Blanc and Mackinac Island and extending down Lake Huron as far south as the northern tip of Saginaw Bay.
“More than 15% of Lake Michigan’s open water (3,528 square miles) and nearly 60% of Lake Huron’s open water (13,611 square miles) could be affected by visible oil from a spill in the Straits,” according to the Graham Sustainability Institute at U-M.
A pledge to clean the wastewater
Enbridge plans to build a temporary water treatment facility to filter out oils, construction material and grease before discharging the water back into Lake Michigan. The firm said that the resulting discharges will meet all the regulations of the National Pollutant Discharge Elimination System.
“The temporary water treatment facility is a central feature of the Great Lakes Tunnel Project construction,” said Paul Meneghini, Enbridge’s community engagement manager for Michigan, in a statement on the firm’s website. “Meeting strict environment standards, the goal is straightforward: Take in water, use it safely, monitor rigorously, treat thoroughly and return it the lake.”
Can Enbridge be trusted?
Organizations such as FLOW, Oil and Water Don’t Mix, and the National Wildlife Federation say no.
They point to U.S. Army Corps of Engineers determination that building the tunnel will result in the loss of wetlands and wildlife habitat; pose a danger of drilling fluids being released into the environment; create six years of traffic, construction noise, light pollutions and vibrations; limit recreational opportunities in the area; destroy archaeological resources; and negatively impact property values and tourism.
“The State of Michigan is the legal trustee of the Straits and has the power and duty to protect them for the benefit of Michiganders and future generations,” said FLOW.
The organization claims that residents of the Great Lakes Basin should not trust Enbridge to protect their water.
The company’s Line 6B spilled a million gallons of heavy crude oil into Talmadge Creek near Marshall, Michigan in 2010, which eventually flowed into the Kalamazoo River. It was one of the worst inland spills in U.S. history. The National Transportation and
Housing Board said the spill was triggered and worsened by “pervasive organizational failures” at the firm.
FLOW counted 34 oil spills, amounting to 1.3 million gallons, from Line 5 in Michigan and Wisconsin. The most recent was a 70,000-gallon spill in Jefferson, Wisconsin, in 2024.
That was the same year that the federal government ordered Enbridge to repair cracks in Line 5 and “employ more comprehensive methods to assess cracks in the line,” according to FLOW, arguing the firm should have done that on its own.
The organization called Enbridge “unaccountable.”
“In 2020, an Enbridge internal investigation revealed that an Enbridge-contracted ship likely dragged an anchor and damaged Line 5 in the Mackinac Straits,” said FLOW on its website. “Enbridge later admitted it failed to notify the state as was required.”
Jim Bloch is a freelance writer based in St. Clair, Michigan. Contact him at bloch.jim@gmail.com.
