MACKINAW CITY, Mich. (AP) — Officials say a multi-agency effort to mitigate potential pollution after a suspected boat anchor strike damaged underwater electric cables and oil pipelines in the waterway that connects Lake Huron and Lake Michigan has wrapped up.

A team led by the U.S. Coast Guard announced the update Tuesday evening. The Coast Guard continues to investigate the cause along with the National Transportation Safety Board, although the state attorney general says a tugboat anchor was dragged across them April 1.

About 600 gallons of mineral oil insulation fluid leaked from two electric cables. Crews finished capping and sealing the cables last month. After the leak was discovered, the multi-agency team responded and surveyed the Straits of Mackinac for pollution.

Also damaged were two oil pipelines and out-of-service electric cables.