A permanent shutdown of Enbridge Energy Co.'s Line 5 oil pipeline could have a major downstream impact on trade with Canada, energy supplies for multiple states and the price of jet fuel for airplanes at Detroit Metro Airport and residential propane in the Lower Peninsula.

Attorney General Dana Nessel has indicated she may go to court as soon as the end of this month to try to stop the flow of oil through Enbridge's 66-year-old underwater pipeline in the Straits of Mackinac.

Enbridge has separately sought a court order enforcing its deal with former Gov. Rick Snyder to build a tunnel under the environmentally sensitive waterway to house Line 5.

The Calgary, Alberta-based company took action after Gov. Gretchen Whitmer wanted to shut down Line 5 within two years — three years before Enbridge says a tunnel sitting 100 feet below the bottom of Lake Michigan could be completed.

"The enormous risk (of an oil spill) that we bear alone as the state of Michigan and the Great Lakes is one that I take very seriously, and it was important to me that have a date certain for shutdown," Whitmer said last week.

The increasingly heated rhetoric has set up a showdown between the Canadian oil pipeline giant and two Democratic statewide officeholders who made campaign promises a year ago to their party's eco-conscious base that they would shut down the underwater pipeline.

Here are five questions and answers about Line 5 and the potential impact of permanently shutting down the pipeline.

Article originally in Crain's Detroit by Chad Livengood

https://www.crainsdetroit.com/energy/qa-what-happens-if-state-shuts-down-line-5-oil-pipeline