Canada invokes pipeline treaty with U.S. in dispute over Line 5 pipeline

Canada is formally invoking a 1977 pipeline treaty with the United States in a bid to prevent Michigan from turning off the taps to Enbridge's Line 5 pipeline.

The dispute stems from a nearly year-old decision by Michigan Gov. Gretchen Whitmer to revoke a 1953 easement to allow the pipeline to cross the Straits of Mackinac connecting Lake Michigan and Lake Huron.

Whitmer cited environmental concerns about the impact a breach from the aging pipeline would have in the area and gave Enbridge six months to close it.

A U.S. federal court ordered the two sides to negotiate, but Michigan stopped participating in those talks in early September.

Canada's lawyer Gordon Giffin says in a letter to a Michigan judge Monday that further proceedings in the case should be halted because Canada is invoking the dispute mechanism of the pipeline transit treaty.