Line 5 Pipeline: Michigan Tunnel

Line 5 crosses more than 280 rivers and streams, many of which are interconnected and flow to the Great Lakes and the Straits of Mackinac, and throughout which Bay Mills has treaty-protected fishing, hunting, and gathering rights. The Great Lakes are the largest source of surface fresh water in the world, supplying drinking water for 48 million people.

Case Overview

Earthjustice, in partnership with the Native American Rights Fund, represents the Bay Mills Indian Community in the Tribal Nation’s fight to protect the Straits and the Tribe’s treaty rights throughout waters in Michigan.

In 2020, Bay Mills Indian Community became the first Tribal nation to intervene in a proceeding before the Michigan Public Service Commission to contest Enbridge’s proposal to build and reroute the Line 5 oil pipeline with a tunnel in the Straits of Mackinac, a 4-mile-wide waterway that connects Lake Michigan and Lake Huron.

The Public Service Commission is one of the agencies that will determine whether Enbridge can build a massive tunnel to house a new segment of its Line 5 pipeline.

In 2010, Enbridge was responsible for the largest inland oil spill in our nation’s history when another of its pipelines (Line 6B) released nearly one million gallons of oil into Michigan’s Kalamazoo River.

In a related case, the Bad River Band of Lake Superior Chippewa is challenging the environmental review of a plan by Enbridge Energy to relocate part of the Line 5 pipeline where it runs through the Bad River watershed. Earthjustice is representing the Bad River Band in its legal fight.

Bob Gravelle, Bay Mills Tribal citizen, fishes on Spectacle Lake in Bay Mills.
Bob Gravelle, Bay Mills Tribal citizen, fishes on Spectacle Lake in Bay Mills. (Whitney Gravelle)

Case Updates

A group of people stand on the bank of a large body of water facing away from the camera, with a large bridge visible on the left of the frame. The shirt on the person on the right reads "NO LINE 5 OIL TUNNEL"
September 19, 2025 Press Release

Michigan Supreme Court Takes Up Challenge to Line 5 Oil Tunnel

Court will hear arguments by Michigan Tribes and environmental advocates

September 19, 2025 document

Line 5 Michigan Supreme Court Order on Application

The Michigan Supreme Court said it will hear a challenge brought by Tribal Nations located in Michigan and environmental advocates who argue that the Michigan Public Service Commission broke state laws in approving Enbridge’s proposal to construct a massive oil tunnel beneath the Straits of Mackinac.

August 29, 2025 document

Line 5 Oil Tunnel Comments to EGLE from Bay Mills Indian Community

Comment letter shared by President Whitney Gravelle of the Bay Mills Indian Community with Michigan’s Department of Environment, Great Lakes, and Energy (EGLE) in considering permits for Enbridge's Line 5 oil tunnel project.