The two oil pipelines that run under the Straits of Mackinac are not unique.
The National Wildlife Federation says there are 5,110 locations across the United States where oil pipelines run through or under navigable waters.
The group says by law, the operators of those pipelines must file an emergency spill response plan with the U.S. Department of Transportation.
The law, the Oil Pollution Act, was passed after the Exxon-Valdez disaster in Alaska.
The NWF filed a lawsuit today alleging that for 20 years, the U.S. DOT has failed to enforce the law, which also requires the agency to approve the plans. The plans must include a worst-case scenario for a spill.
"Oil pipelines can and do rupture," says Neil Kagan, the NWF's senior counsel. "There have been in fact hundreds if not thousands of spills over the years, and so – we need to be prepared. There have been spills from pipelines in the water in Texas, California, Nebraska, Kentucky. This is a nationwide problem."
Enbridge Energy recently conducted an emergency spill response drill at the Straits of Mackinac.
The NWF's Mike Shriberg says if Enbridge did in fact file an emergency response plan with the U.S. DOT for Line 5, it was on a voluntary basis, and the plan may not have even been reviewed by the agency.
He says his group has sent divers and cameras under the Straits to obtain photos of the pipelines, and discovered some supports had broken, indicating corrosion, and there was debris lying over sections of the pipe.
Enbridge maintains that the pipeline is in excellent condition.
A spokesperson from DOT did not respond to a request for comment.