Enbridge Energy says one of the two oil pipelines running under the Straits of Mackinac was dented less than one inch in an apparent anchor strike on April 1st.
The Associated Press reports Enbridge on Monday told the Michigan Pipeline Advisory Board that the incident resulted in two dents -- one about 3/4 inch deep and another that was less than 1/2 of an inch deep.
The pipeline's walls are one-inch thick, but the dents did not cause a reduction in thickness.
The same incident caused damage to two electric cables int he water way, resulting a 600-gallon insulation fluid spill.