Michigan's Governor Gretchen Whitmer said on Nov. 13 she was revoking a nearly 70-year-old easement that could force Canada's Enbridge to shut down a pipeline that delivers fuel and oil to the U.S. Midwest.

The move would require the line to be shut by May 2021. Whitmer said that Enbridge has failed to protect the U.S. Great Lakes, where the pipeline runs, by preventing the line from being damaged.

The Enbridge Line 5 pipeline runs under the Straits of Mackinac, where Lakes Huron and Michigan meet, and ships 540,000 bbl/d of light crude oil and propane, serving both retail customers and refiners in Michigan and Ohio. It is a critical part of the company's network that delivers the bulk of Canadian crude exports to the U.S. and eastern Canada.

"Transporting millions of gallons of petroleum products each day through two 67-year old pipelines that lie exposed along the entire span of a busy shipping channel presents an extraordinary and unacceptable risk," Whitmer's office said in a statement.

A legal notice filed by state Attorney General Dana Nessel cites Enbridge's "violation of the public trust doctrine” and noncompliance with easement conditions as reasons for the revocation.

It is unclear if Whitmer's move will succeed in getting the line shut. Enbridge had reached an agreement with her predecessor, Rick Snyder, to build a tunnel surrounding the existing pipeline to protect against leaks that could contaminate the waters. A state court upheld that agreement

“The governor is holding [Enbridge] accountable for their irresponsible behavior that threatens the Great Lakes every single day," said Sean McBrearty, campaign coordinator for regional environmental group Oil & Water Don’t Mix.

Enbridge said in a statement it is currently reviewing the legal notice, adding that there is no credible basis for terminating the easement.

“This notice and the report from Michigan Department of Natural Resources are a distraction from the fundamental facts,” said Vern Yu, president of Liquid Pipelines at Enbridge.

"Line 5 remains safe, as envisioned by the 1953 easement, and as recently validated by our federal safety regulator."

Whitmer created a task force in 2019 to explore alternative supply sources; her statement Nov. 13 says the plan is to find an "orderly transition" to find other energy sources.