MACKINAW CITY, Mich. -- The Coast Guard Unified Command approved a plan to cap and seal two severed utility cables in the Straits of Mackinac on Wednesday, May 2.

On Thursday, a barge, tugboat, and remotely operated submerged vessel initiated efforts to cap the ends of the two severed ATC utility cables.

The ends of the severed cables will be individually lifted to the surface of the water, to be soldered and have a permanent cap affixed onto them.

During the operation, a back pressure will be applied to the shore sided ends of the cables in order to prevent any further spillage of mineral oil into the Straits of Mackinac.

According to an environmental report, nearly 615 gallons of mineral oil have been extracted from the two severed cables in an ongoing effort to clean up the Straits. The two affected cables hold a maximum of 800 gallons of mineral oil combined.

The cables were installed in 1956 but were deenergized and put into retirement in 1990.

There is an ongoing investigation by the Coast Guard marine casualty investigation into vessel activity that may have initiated the mineral spill.