State officials say the flow of crude oil through twin underwater pipelines has been halted temporarily because of high winds and waves in the channel where Lakes Huron and Michigan meet.
The Michigan Agency for Energy says the temporary shutdown of Enbridge Inc.'s Line 5 is in keeping with a November agreement between the state and the Canadian oil transport company.
Under the deal, operation of the line will stop when bad weather causes wave heights of 8 feet (2.4 meters) or higher for longer than an hour.
Waves exceeded 9 feet (2.7 meters) Tuesday.
The state agency says Enbridge shut down the lines at 11:37 a.m. EST and will resume the oil flow when conditions improve.
Line 5 carries oil from Superior, Wisconsin, to refineries at Sarnia, Ontario.