Noted environmental attorney Jim Olson educated us on the Enbridge Line 5 pipeline under the Straits of Mackinaw.  Jim is the founder and President of FLOW ("For Love of Water"), the non-profit whose mission is to advance public trust solutions to save the Great Lakes.
Under the Public Trust Doctrine, waters within Lake Michigan and other lakes within the State are held in trust by the State on behalf of the public.  Thus, when Canadian oil company Enbridge built its Line 5 pipelines in Lake Michigan in 1953, it could do so only after obtaining an easement from the State subject to the Public Trust Doctrine.
While Enbridge has a large network of pipelines in the state, there was little public concern about their safety until 2010, when there was a breach in Enbridge Line 6B, resulting in a massive spill in the Kalamazoo River.  Since the two 20" pipelines in Line 5 are more than 50 years old and are completely covered by zebra and quagga mussels, their structural integrity is suspect.  Furthermore, a spill at the bottom of Lake Michigan would be far worse than one occurring on land. Consequently, FLOW and other non-profit advocacy groups have been getting out the facts surrounding Line 5.  FLOW believes that if they get out the facts and the legal principles, the advocacy will speak for itself.
Recognizing that the State has jurisdiction of this issue, Attorney General Bill Schuette has appointed a task force looking into the safety of Line 5.  The Public Safety Advisory Board is to study this issue and issue its report within a year.  This should include an independent risk analysis and a determination of appropriate insurance coverage based on a worst case scenario.  Enbridge has agreed not to ship heavy crude via Line 5 but has not been forthcoming regarding its own study of alternatives.  FLOW believes that in the meantime there should be no flow over Line 5 in the winter (since cleanup in the winter would be impossible), as well as a return to the original flow rates.
In conclusion Jim urged us to contact the Attorney General and Governor with respect to this issue.