Enbridge Line 5 Tunnel

File No. LRE-2010-00463-56-A19

Project Update (3/7/2022)

The Corps of Engineers, Detroit District has selected Potomac-Hudson Engineering, Inc. (PHE) as the third-party contractor for preparation of the Environmental Impact Statement (EIS) for its permit review of Enbridge’s proposed Line 5 Tunnel under the Straits of Mackinac.  PHE will be paid by Enbridge but directed by the Corps.  The Corps is responsible for the scope and content of the EIS and will direct PHE in the EIS preparation.

In the coming months, the Corps will publish a Notice of Intent to prepare an EIS in the Federal Register, which will begin the scoping period for the EIS.  The Notice of Intent will invite public comment on the impacts and alternatives that should be evaluated in depth in the EIS.  Members of the public may request to be notified when the Notice of Intent is published by sending an email to  

The website for the Line 5 Tunnel EIS will soon transition to a website managed by PHE, and a link will be posted here when it is available.

Project Update (6/24/2021)

The Corps of Engineers will prepare an environmental impact statement (EIS) to evaluate the proposed Line 5 pipeline tunnel.  The EIS will provide for a thorough review of potential impacts and reasonable alternatives and will inform a permit decision on Enbridge’s application.  Details on the EIS development will be updated on this website when available.  More information on the announcement is available at:

Project Update (2/1/2021)

The U.S. Army Corps of Engineers, Detroit District, continues to conduct its independent review in accordance with federal regulations. There is no specific timeframe for the Corps' decision.

The Michigan Department of Environment, Great Lakes, and Energy (EGLE) issued an National Pollutant Discharge Elimination System (NPDES) permit and a draft permit under Part 303, Wetlands Protection, and Part 325, Great Lakes Submerged Lands, for the project on January 29, 2021.  EGLE permit decision documents can be found at:,9833,7-413-100616-550690--,00.html.  EGLE permit issuance is a prerequisite for Corps permit issuance.  USACE may use information generated for the EGLE permit reviews in our analysis.

Between our initial public notice and the comment period associated with our December 7, 2020 public hearing, we received over 15,000 comments.   We are reviewing the comments to help identify specific information needs that we will ask Enbridge to address.

Project Summary

Enbridge Energy, LP, has submitted an application for a Department of the Army (DA) permit to construct a pipeline tunnel under the bed of the Straits of Mackinac between Point LaBarbe, St. Ignace, Mackinac County, and McGulpin Point, Mackinaw City, Emmet County, Michigan.  The tunnel would house a new 30-inch pipeline for light crude oil and liquid natural gas which would replace the existing dual submerged Line 5 pipelines crossing the Straits of Mackinac.

A detailed project description is in our public notice.

The purpose of the proposed work is to transport light crude oil and liquid natural gas between the upper and lower peninsulas of Michigan.

Project Location

Contact Information

USACE Detroit District Regulatory Office

477 Michigan Avenue

Detroit, Michigan 48226

Related Sites

State of Michigan Line 5 Website