Michigan regulators approve Enbridge Line 5 tunnel permits Updated Jan 29, 2021; Facebook Share LANSING, MI — Michigan environmental regulators have approved several permits that Enbridge Inc. needs to build a tunnel underneath the Straits of Mackinac that would house a replacement section of the Line 5 oil pipeline. The Michigan Department of Environment, Great Lakes, and Energy (EGLE) said today that it approved applications to discharge wastewater into the lakes and perform construction work in protected wetlands, which are among the authorizations Enbridge needs to build its proposed $500 million utility tunnel next to the Mackinac Bridge. The permits are not the final word on the tunnel project, which still needs to clear similar federal approvals and must yet get through a lengthy review by the Michigan Public Service Commission (MPSC).