Crews continue oil removal at Straits of Mackinac

Beth LeBlanc
The Detroit News

Crews continue to remove the remaining mineral oil from two damaged utility lines beneath the Straits of Mackinac.

About 250 of the roughly 800 gallons of remaining mineral oil have been vacuumed from the 3.5-mile utility line since last week, according to the U.S. Coast Guard. The oil occupies a less than one-inch diameter space in the cable and is used as an insulator.

The utility lines, owned by Pewaukee, Wisconsin-based American Transmission Company, were shut down on Tuesday after they had leaked an estimated 600 gallons of the coolant fluid into the straits.

Experts with the Coast Guard and environmental and wildlife agencies have yet to see evidence of an oil sheen at the site, nor any apparent impact to surrounding wildlife, the Coast Guard said in a Monday statement.

The two utility lines are among six that create two circuits that carry power between the state’s two peninsulas.

Lt. (junior grade) Sean Murphy, a spokesman for the U.S. Coast Guard, said the agency continues to investigate the damage to the lines, which officials believe may have been caused by “vessel activity.”

Murphy said two other companies who own lines crossing the straits — Enbridge Energy and TransCanada — were told to check their infrastructure for similar damage. Murphy said ATC, Enbridge and TransCanada operate a total of nine utility and transmission lines beneath the straits.

ATC spokeswoman Jackie Olson said the company is working to put a remote-operated vehicle into the water to inspect its utility lines.

Murphy said crews have not yet obtained visuals of the lines beneath the straits, but the damage is believed to be limited to the two ATC utility lines.

“They’ve checked their infrastructure and they have no reason to believe there is any other damage,” Murphy told The Detroit News.

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