LANSING - A 4.5-mile long utility tunnel under the Mackinac Straits to encapsulate the Line 5 petroleum pipeline will be constructed, said an Enbridge Energy Co. spokesman last month.

No it won't, said Michigan Attorney General Dana Nessel and then Gov. Gretchen Whitmer on March 28, at least not under the terms of how state lawmakers and Governor Rick Snyder approved the mechanism to make it happen. Nessel issued an opinion - which is essentially law unless a court says it isn't - that invalidated legislation passed by the GOP-led state Legislature and signed by Snyder to create an authority to build and operate the tunnel exceeded 

Nesssel' argument against the validity of the law, which was adopted last December in the prior legislative term, is a technical one. Her opinion said the law "exceeds the scope of what is generally reflected in the title," violating the state Constitution. The law in question, Public Act 359 was hastily written in the Legislature's lame duck session. It created the Mackinac Straits Corridor Authority to authorize the tunnel's construction, but the amended title of the act did "not provide ‘fair notice’ of an imminent tunnel agreement authorizing the construction of a utility tunnel," Nessel wrote.

Whitmer immediately issued her statement on the matter: “I agree with the conclusion reached by Attorney General Nessel. The Great Lakes are our most precious resource in Michigan, and because of their significance, I’ve instructed state departments and agencies to halt any actions in furtherance of this law.”  

A statement from Enbridge said it was “surprised and disappointed” by Nessel’s opinion and said the line "will continue operating safely as it has for more than 60 years." The company said it will ask the Whitmer administration to clarify the "path forward.”

The courts will almost certainly have the final say on the impasse. Here's the back-story on Line 5 and the proposed tunnel:

There isn't much controversy over the vast majority of Line 5, the Enbridge Energy Co.'s 645-mile, mostly 30-inch-diameter pipeline that travels from Superior, Wisconsin and terminates in Sarnia, Ontario. 

But the 4.5-mile long section under the Straits of Mackinac between St. Ignace and Mackinaw City is a completely different story. Years of environmentalists'  protests over the continued operation of the Line 5 pipeline's dual 20-inch steel lines that sit atop the Straits' lake bed led to a landmark agreement late last year between Enbridge and the state Legislature and governor.

Enbridge agreed to build a new utility tunnel just west of the Mackinac Bridge, 100 feet through bedrock below the Straits, and encase replacement petroleum pipelines as well as conduit for other utility lines like telecommunications and electrical grid cables. There are still regulatory, and certainly legal hurdles that will slow the construction of the tunnel, but Enbridge's Peter Holran told a building trades audience last month that the obstacles will be overcome. "We're very cognizant of what is in front of us," Holran said. "We're very thoughtful about how we will be moving forward. But let me say, we are going to build the tunnel. We are going to build the tunnel."

Holran, Enbridge's director of external affairs, addressed an audience of building trades delegates on March 6 at the 60th Legislative Conference of the Michigan Building and Construction Trades Council. Construction of the tunnel, which could cost $500 million, would create hundreds of building trades jobs in a region of the state that is traditionally sorely lacking in major building projects.

The timeline for the project was already in full swing, Holran told delegates, although Nessel's opinion has thrown a wrench into the works. Enbridge has been waiting on permits from the state Department of Environmental Quality, and the Army Corps of Engineers, and had hoped to have them approved this month. The company then expected to start to perform geological pre-engineering work and then design the scope of the project, a process which Holran said should be complete by mid-2020. 

Barring delays in permitting or legal action - and delays are even more likely now -  the company would then enter into a contract with a tunneling company. "Enbridge does pipelines, we don't do tunnels," Holran said. Once the design and tunneling contracts are in place, which is expected by the end of 2020, it is expected to take the next two years to get permits to assemble the equipment, to stage the job, and to be prepared to get to work.

"There's no such thing as 'boring machines are us.' You just don't go out and buy a boring machine, especially when you're building a 12- or 15-foot tunnel. They have to be specially made," Holran said. "Every one is unique, for the rock it's going through, for the environment it's in, for the construction that's going to take place. What I'm told is if we find the rock formation we believe is down there it should take about two years to drill the tunnel, about 40 feet a day is what the machine can do. 

"It moves along, methodically, and what the boring machine will do is actually bore out the tunnel and the cement lining is going to be built in behind the tunnel as it moves through. Very sophisticated machines."

Holran added: "We firmly believe we can have (the tunnel) in place by the end of 2024."

While the dual Line 5 pipelines under the Straits of Mackinac have never leaked, there is growing clamor about their age (they were placed in 1953) and a rupture from a ship's anchor strike or some other accident. A major petroleum leak, of course, would be devastating to the Great Lakes. 

There is a strong environmental lobby that not only wants Line 5 replaced, but shut down. Their concerns are being heard by Whitmer and others, especially given Enbridge's responsibility for one of the nation's worst inland oil spills, a 2010 pipeline break that that fouled a 40-mile stretch of Michigan's Kalamazoo River. The company's $1.2 billion cleanup effort took nearly five years. 

But proponents of the new tunnel point to the increased safety factor of getting the pipelines out of the water. Businesses and residents in the Upper Peninsula utilize Line 5 for delivering a significant portion of their propane. And if the pipeline were to be re-routed, where would it go?

Whitmer told the same building trades audience last month that she had not taken a position on supporting the tunnel's construction. 

"Now I have not come out against a tunnel. I have not come out in favor of a tunnel," Whitmer told the trades delegates. "I have simply said if we are going to go that route, or if we are going to get that line out of the water, we have to have a plan to deliver energy to the U.P. and we have to have a real process where we hear from labor, we hear from the company we hear from the residents and we have a real transparent conversation about it to make the right decision. I don't know what is the right decision. But I want the time and the information so that we're making one. You guys will have a seat at that table when we do it. But I do know that line in the water I think is precarious, and I think the last administration moved forward in this fashion."

Upper Peninsula State Rep Sara Cambensy (D-Marquette) in December helped round up several Democratic votes to help make the House vote to create a Line 5 tunnel authority a bipartisan one. "We knew the Line 5 vote was going to be controversial,"  she said. "The Anti-Line 5 people were so in our face." She cited the importance of the building trades jobs that would be created.

"None of us want oil and water to mix," she told building trades delegates. "But none of us rode horses here. We have a duty to do this right." She received a round of applause for getting an amendment inserted in the legislation that puts a priority on using Michigan labor for the Line 5 Tunnel project. 

Holran later paid tribute to Cambensy, former State Rep. Scott Dianda and Michigan Building and Construction Trades Council President Steve Claywell for their work on supporting the Line 5 legislation. He told the delegates that "Enbridge didn't need that amendment, but we welcome it. Enbridge's commitment is that we are going to hire local labor, we are going to hire local companies. We are going to hire the local talent necessary to build our project. We want the best talent, and that's represented by the folks here in this room. We know that."