In a one-two legal punch, Michigan Attorney General Dana Nessel has responded to a lawsuit filed by Enbridge Inc. in June and simultaneously has taken the first step to decommission the Calgary operator’s 66-year-old dual oil pipelines that run through the Straits of Mackinac.

Nessel filed a lawsuit in Ingham County Circuit Court to prepare to decommission the system, and she filed a motion to dismiss Enbridge’s case filed in the Michigan Court of Claims. Enbridge is seeking to enforce agreements made in the waning months of Republican Gov. Snyder’s administration, which authorized Enbridge to build a tunnel below the bottom of the channel between Lake Huron and Lake Michigan as a safety measure, and allowing it to continue to operating Line 5.

Gov. Gretchen Whitmer and Nessel, both Democrats, took office in January after campaigning in part to shutter the oil system. Whitmer, acting on a memorandum by Nessel, in March ordered state agencies to stop all actions regarding the tunnel.

“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,” Nessel said. “Gov. Whitmer tried her best to reach an agreement that would remove the 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.”

The state’s lawsuit asks the Ingham County 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.”

The lawsuit identified a “potential anchor strike” as the most significant risk to Line 5. In 2017, the state’s contractor, Dynamic Risk Assessment Systems Inc., identified an anchor strike as the most “dominant threat” to the pipeline.

“The location of the pipelines, which carry millions of gallons of oil each day and lie exposed in open water at the bottom of the Straits, combines great ecological sensitivity with exceptional vulnerability to anchor strikes,” said Nessel.

“This situation with Line 5 differs from other bodies of water where pipelines exist because the currents in the Straits of Mackinac are complex, variable, and remarkably fast and strong.”

The continued operation of Line 5 “presents an extraordinary, unreasonable threat to the public because of the very real risk of further anchor strikes, the inherent risks of pipeline operations, and the foreseeable, catastrophic effects if an oil spill occurs at the Straits.”

The state is seeking a court order to shut down and decommission the pipelines as soon as possible after a reasonable notice period to allow orderly adjustments by affected parties.

Nessel also filed a motion for summary disposition in the Court of Claims arguing that Michigan’s Public Act (PA) 359 passed in 2018 under the former governor to create a Straits Corridor Authority (SCA) was unconstitutional.

The agreements “purported to give Enbridge the right to build a tunnel and continue operating Line 5 in the Straits for the estimated seven to 10 years it would take to build the tunnel are invalid.”

Nessel’s office has informed all state agencies, including the SCA, that PA 359 and any agreements relying on the statute are unenforceable.

“The debate over Line 5 has been raging for over five years,” said Nessel. “Real-world events have shown me we can’t wait another five to 10 years for Enbridge to build a tunnel. We cannot prevent accidental or emergency anchor deployments in one of the busiest shipping channels in the Great Lakes. And it only takes one such incident to cause an environmental and economic catastrophe. That is a risk no one should be willing to take.”

Enbridge said Friday it would “respond in due course” to the legal actions. However, management also said it shared the “governor’s vision of protecting the Great Lakes and reducing the risk to the Straits of Mackinac. Enbridge remains fully committed to moving forward in a constructive manner with the administration to reach our mutual objective of replacing the existing Line 5 crossing as soon as possible.

“We believe that the most effective path forward is to work expeditiously toward permitting and construction of the tunnel, rather than through the courts. Evidence of our commitment to work collaboratively includes continuation of our $40 million 2019 engineering and geotechnical program, which will allow us to maintain the earliest possible in-service date for the crossing.”

In the meantime, Enbridge said it would “continue to assert its rights in the courts to ensure we safely meet the critical energy needs of Michiganders.”