A draft environmental study finds that Enbridge's proposed Line 5 tunnel beneath the Straits of Mackinac would have mostly temporary environmental impacts, primarily during construction. Long-term, the tunnel is deemed to reduce oil leak risk, though some wetland loss is expected. A 30-day public comment period has begun, with a final decision expected this fall. Environmental groups oppose the project, citing the risk of a Great Lakes oil spill, while supporters highlight its economic importance. The study also analyzed alternatives, including doing nothing or covering the existing pipeline, finding the tunnel to be the safest option.

Prepared by Olivia Bennett and reviewed by editorial team.