Whitmer's office has maintained that an oil spill would cause substantial harm to Michigan's economy and the Great Lakes. Last week, Ohio Attorney General Dave Yost filed an amicus brief asking a federal judge to block the shutdown order, arguing on behalf of Ohio refineries and the state of Louisiana that closing the submerged line would cause economic hardship beyond Michigan. Related stories: Republicans press Biden to keep Line 5 open Canadian minister: 'Operation of Line 5 is non-negotiable' Some propane suppliers switching to rail in Michigan Shutdown order 'creates a scenario' for stopping tunnel Line 5 shutdown order heralded as 'enormous victory' Possible Ice Age artifacts ignored by Line 5 tunnel survey Enbridge in Michigan: A timeline Fight to shutter Line 5 pipeline has waged for years Line 5 is bent, deformed where Enbridge wants to anchor it