The Mackinac Bridge.

A break in the aging pipeline that crosses under the pristine waters of the Straits of Mackinac could be catastrophic for the Great Lakes. Is the old pipeline a threat? Elizabeth Brackett brought us the story in June. We take another look in this encore presentation.

The Great Lakes contain 90 percent of the fresh water in the U.S. and the Straits of Mackinac have some of the most pristine water in the Great Lakes. But underneath the water are more than 60-year-old pipelines carrying crude oil and natural gas. Elizabeth Brackett has the details.