Canada asked a federal court in Michigan to suspend proceedings involving a dispute between the state and Alberta-based Enbridge, owner of a dual natural gas and oil pipeline system operating under the Straits of Mackinac, after invoking a 1977 treaty with the U.S. to negotiate the disagreement stemming from the state’s demand that the line be shut down.

In a letter to U.S. District Court Judge Janet Neff, Canadian Counsel Gordon Giffin said the formal request invoking the treaty was presented to the U.S. through diplomatic channels and is a formal request for negotiations under the terms of the treaty.  

The treaty specifically says that “no public authority in the territory of either party shall institute any measures which are intended to, or which would have the effect of, impeding, diverting, redirecting, or interfering with in any way the transmission of hydrocarbons in transit,” Giffin said.

Under the treaty it is “neither necessary nor proper” for the court to make any determinations that could “undermine, conflict or interfere with the obligations and processes established by the treaty,” his letter says.

Michigan defended its order that a four-mile section of the pipeline on the Lake Michigan Lake Huron lakebed under the straits be shut down based on what it said are Enbridge’s “persistent and incurable violations of its responsibility to exercise due care” during operations. Enbridge sued the state, disputing its revocation of an easement to operate.

“I am profoundly disappointed that today the Government of Canada chose to invoke Article IX of the 1977 Transit Pipelines Treaty in a bid to help Enbridge, a private oil company, keep crude oil running indefinitely through Michigan's Straits of Mackinac,” Gov. Gretchen Whitmer said in a statement, claiming a threat of a catastrophic oil spill in the Great Lakes.

Enbridge is building an estimated $500-million tunnel up to 100 ft under the lakebed that will hold a new section of Line 5 and other future projects. Design and engineering by Arup is complete, company spokesman Ryan Duffy told ENR, and a preconstruction contract awarded last year to Jay Dee Contractors Inc., Livonia, Mich. and the U.S. unit of Japan's Obayashi Corp. ended earlier this year.

Duffy said the company hopes to release the RFP for a construction contractor in mid-October if given permission by the Mackinac Straits Corridor Authority.

There already is interest from a telecommunications company to also place fiber optic cable in the approximiate four-mile new tunnel, Duffy said. Since Michigan would take ownership of the tunnel when construction is finished, it would be able to negotiate with companies to place cable or pipelines inside the tunnel, he said.   

A decision in June by the US Army Corps of Engineers to perform a more rigorous environmental impact statement review rather than a shorter environmental assessment has delayed construction and estimated operations by about two years past the original 2024 date.

Enbridge has invested more than $100 million on safety enhancements to Line 5 and to better assure the safety of the dual pipelines until the tunnel is built, Duffy said.