The U.S. Army Corps of Engineers, Detroit District published the Line 5 Tunnel Project Draft Environmental Impact Statement (DEIS) May 30, 2025.

The Detroit District is conducting a 30-day public comment period on the DEIS from May 30 to June 30, 2025. The public and concerned parties are welcome to provide comments using the following methods:

• Written comments (post marked by June 30, 2025) mailed to:

Line 5 Tunnel EIS

6501 Shady Grove Road, P.O. Box 10178

Gaithersburg, MD 20898

• On the Line 5 Tunnel EIS website 

• Virtual public meetings scheduled for Wednesday, June 18, 2025, 1-4 p.m., and Wednesday, June 25, 2025, 5-8 p.m.

“Public participation is an important part of the National Environmental Policy Act (NEPA) process to ensure a thorough environmental analysis, and an effective, consistent and well-informed decision,” Detroit District Commander Lt. Col. Wallace Bandeff said.

All submitted comments are included in the Detroit District’s administrative record, analyzed and considered in the preparation of the Final EIS and other parts of the District’s review, as applicable.

“Even when operating under emergency procedures, the Detroit District remains committed to following the NEPA process,” said Lt. Col. Wallace Bandeff.

The Line 5 Tunnel Project is a proposal by Enbridge Energy, Limited Partnership (Enbridge) to construct a tunnel beneath the Straits of Mackinac in Lake Michigan. The tunnel would house a replacement segment of Enbridge’s Line 5 pipeline, which transports crude oil and natural gas liquids. The Detroit District is reviewing Enbridge’s permit application (File LRE-2010-00463-56-A19) pursuant to Section 10 of the Rivers and Harbors Act of 1899 and Section 404 of the Clean Water Act for a Department of the Army permit.

The EIS assesses the potential impacts of the Line 5 Tunnel Project and project alternatives (including the No Action alternative, an alternative that would install a protective gravel/rock cover over the existing Dual Pipelines in the Straits, and multiple pipeline decommissioning sub-alternatives, if the proposed tunnel were to be permitted) to land use and recreation; aesthetics; water resources; biological resources; cultural resources; geology; soils; transportation and navigation; air quality; noise and vibration; socioeconomics; and reliability and safety.

In addition to its consideration of cultural resources in the EIS, the Corps of Engineers is separately evaluating impacts to historic properties, as well as impact avoidance, minimization and mitigation measures, in accordance with Section 106 of the National Historic Preservation Act

The Corps of Engineers is also conducting a treaty rights analysis in consultation with federally recognized Tribes to determine if the proposed Line 5 Tunnel Project would impinge upon or abrogate treaty rights. Findings of the Section 106 process and treaty rights analysis will be presented in the Record of Decision following release of the Final EIS.

The Record of Decision date is anticipated in fall 2025.