There's a midnight deadline for Enbridge to shut down its Line 5 pipeline in the Straits of Mackinac.
The company says they have no intention of shutting down.
Enbridge says only the federal government has the authority to order a shutdown.
The Canadian company and its supporters say doing so would risk the same fuel disruptions experienced on the East Coast following a cyberattack against a pipeline there.
Opponents say the two situations are different and accuse Enbridge of flouting the law.