LANSING  - Michigan Attorney General Dana Nessel and Enbridge Energy have formally entered a legal battle that will determine the fate of the proposed Line 5 tunnel under the Straits of Mackinac.

The battle has been simmering for most of this year, with Nessel working to fulfill her pledge to shut down the pipeline tunnel and Enbridge filing its own lawsuit seeking enforcement of an agreement made late last year by then-Gov. Rick Snyder and the Michigan legislature that green-lighted the construction of the tunnel.

The proposed utility tunnel would be bored into bedrock under the Mackinac Straits, and encapsulate a 4.5-mile section of a vital petroleum and natural gas pipeline that runs the length of the Upper Peninsula from Superior, Wisconsin, through the Straits, then south and east to Sarnia, Ontario. Currently, dual steel pipelines placed on the lake bed from St. Ignace to Mackinaw City in 1953 perform that task, but they are unprotected from anchor strikes and no one is sure of their lifespan.

“I have consistently stated that Enbridge’s pipelines in the Straits need to be shut down as soon as possible because they present an unacceptable risk to the Great Lakes,” said Nessel when she made the filing on June 27 in Ingham County Circuit Court. “Governor Whitmer tried her best to reach an agreement that would remove the dual 20-inch pipelines from the Straits on an expedited basis, but Enbridge walked away from negotiations and instead filed a lawsuit against the state.  Once that occurred, there was no need for further delay.”

At the same time, Nessel filed a motion to dismiss Enbridge’s lawsuit in the Court of Claims on June 6 seeking to enforce agreements made in the last months of the Snyder administration that essentially authorized the Line 5 Tunnel, which transports millions of gallons of petroleum products daily.

An Enbridge statement on June 28 said that "we will respond in due course as part of the court’s process and we are comfortable with the case we can make as described in our filing June 6. These agreements were a major accomplishment for the State of Michigan and were only possible after extensive negotiations with State officials. They included various commitments by Enbridge and the construction of a $500 million tunnel at the Straits crossing to house a new Line 5. 

"This would further reduce the risk to the Straits to near-zero and provide for continued safe operation of the existing system until completion of the tunnel, thereby assuring undisrupted supply to Michiganders and surrounding regions." 

Construction of the utility tunnel would take an estimated five years and would be an unusually large, but welcome, project for that area of Michigan. The Michigan Building and Construction Trades Council supports the construction of the Line 5 Tunnel. 

Nessel’s summary of the lawsuit asks the Ingham County Circuit Court to find that Enbridge’s continued operation of the Straits pipelines under the easement granted by the State in 1953 "violates the public trust doctrine, is a common law public nuisance, and violates the Michigan Environmental Protection Act because it is likely to cause pollution impairment and destruction of water and other natural resources."

Her office, citing a State of Michigan-sponsored study of the situation in 2017 by Dynamic Risk Assessment Systems, Inc., identified an anchor strike as the most “dominant threat” to Line 5. "And it only takes one such incident to cause an environmental and economic catastrophe," Nessel said.

Enbridge has already initiated plans to built the tunnel. The energy company pointed out that for the existing pipelines, safety measures "include the use of extra heavy wall pipe (.812 inches); a robust cathodic protection system to prevent external corrosion; anchor devices to counter the effects of water currents; operating the crossing at less than 25 percent of maximum operating pressure to provide a significant safety margin well beyond normal pipeline operations; and frequent inspections, including the use of sophisticated in-line inspection tools, divers and remotely operated vehicles to confirm the integrity of the crossing."

There is significant debate about the economic effects to Michigan and the region of simply shutting down Line 5. According to the Michigan Oil and Gas Association, about 30 percent of the light crude on Line 5 stays in the state. The groups says the pipeline supplies 28 percent of the product taken in by Michigan's only petroleum refinery, the Marathon plant in Southwest Detroit. The pipeline also serves the BP Husky refinery in Toledo and refineries in Sarnia, Ontario. Opponents of shutting down Line 5 say that turning off the tap would result in a significant increase in rail car and truck transportation of petroleum products, a set up which offers its own set of real and potential environmental threats. 

In addition, the oil and gas association said Line 5 delivers 85 percent of the propane that heats Upper Peninsula and northern Michigan homes, whose supply would have to, again, be replaced by truck or rail cars.

Pushing for the closure of Line 5 is a group called "Oil and Water Don't Mix, who have repeatedly pointed out that the pipelines had no business being sited in the Straits of Mackinac because of the environmental sensitivity of the area.