CALGARY, Alberta—Canadian pipeline company Enbridge Inc. said on Sept 24 it has received a permit from the U.S. Army Corps of Engineers to install 54 steel supports along its underwater Line 5 pipeline in Michigan's Straits of Mackinac.

Line 5 ships 540,000 barrels per day of light crude oil and propane and is a critical part of Enbridge's Mainline network, which delivers the bulk of Canadian crude exports to the United States.

However the Michigan is suing Enbridge in a bid to have the underwater portion of the 66-year-old twin pipelines, which run beneath the straits where Lakes Huron and Michigan meet, decommissioned to remove any risk of a leak.

In August Enbridge identified a span, or gap between the pipe and the lake bed, exceeding 75 feet, which under easements granted by the state of Michigan is the limit for each span.

Company spokesman Ryan Duffy said Enbridge had started work immediately to install a support at that span.

"We expect that weather permitting, we will complete work on the span measuring more than 75 feet later this week," he added in an emailed statement.

Onshore