Line 5 pipeline issue overshadows tunnel permit process

July 8, 2020 By    

The National Propane Gas Association (NPGA) and the Michigan Propane Gas Association (MPGA) submitted comments to the Army Corps of Engineers as part of Enbridge’s permit application to build a tunnel through the Straits of Mackinac that would house the company’s Line 5 pipeline.

Enbridge Line 5 is an important piece of energy infrastructure for Michigan, the Midwest and the surrounding states, NPGA shares in its comments. Line 5 carries natural gas liquids and light crude oil to Sarnia, Ontario, Canada, where the feedstocks are refined and fractionated into propane and other energy commodities.

“The MPGA believes that the construction of this tunnel and the replacement of the segment of Line 5 ensures the safe transportation of the propane consumed throughout our state and region,” the MPGA adds in its letter to the Corps of Engineers’ Detroit District, noting how the state’s propane businesses sell about 500 million gallons of propane annually and service over 600,000 customer accounts.

Separately, the Michigan Department of Environment, Great Lakes, and Energy continues to review its application, Enbridge says.

The Great Lakes Tunnel Project would replace two existing segments of Line 5 with one new line contained in a tunnel under the Straits. Pending receipt of all necessary permits and approvals, Enbridge says it anticipates beginning construction of the Great Lakes Tunnel in 2021, with the replacement Line 5 segment operational in 2024.

Pipeline issue discovered

Separately, as part of its seasonal maintenance work, Enbridge discovered an anchor support issue on the east leg of the pipeline June 18 and reported it to Michigan officials.

According to Enbridge, a screw anchor assembly on the east leg had shifted from its original position, affecting only the anchor support assembly and not the pipeline. The company shut down both legs of the dual pipelines crossing the Straits as a precautionary measure.

Enbridge restarted the west leg a couple of days later after a review and consultation with the Pipeline and Hazardous Materials Safety Administration (PHMSA), according to the company. The decision to restart the west leg drew criticism from state leaders, who had sought more information and discussion about potential damage to the anchor support.

“We have been working very closely with the Pipeline and Hazardous Materials Safety Administration to ensure it is able to assess the safety of the dual pipelines,” says Vern Yu, Enbridge’s executive vice president and president of liquids pipelines in a company press release. “This included informing them of our completion of remote operated vehicle inspections of the west leg of the line, which confirmed there was no mechanical damage to the pipeline or any support anchors. We have also provided engineering assessments and other materials to state officials. We continue to work with PHMSA to answer their questions about our assessments of the dual pipelines.”

However, on June 25, the Ingham County Circuit Court in Michigan issued a temporary restraining order requiring Enbridge to shut down Line 5 through the Straits of Mackinac until a hearing on the state’s request for a preliminary injunction could be held. Michigan Attorney General Dana Nessel had filed the motions, asking the court to order Enbridge to provide all information related to the issue and to suspend pipeline operations until the state had time to review it.

“Enbridge is disappointed in the court’s ruling as we believe that Line 5 is safe; however, the west leg of Line 5 has been shut down,” says Yu, noting how the company already had shut down the east segment of the pipeline pending further review.

On July 1, the Ingham County Circuit Court amended its temporary restraining order that required Enbridge to temporarily shut down the west segment of Line 5. It allowed the company to resume partial operation of the line but under court orders to share information from further inspections. Pursuant to the court order, Enbridge says it will conduct an inline inspection tool run on the west segment and share its findings with the state.

“Today’s court decision allows the state to receive the vital information surrounding this incident that we need to complete an informed analysis of the damage and evaluate the threat this pipeline poses to our environment if left to operate in its current state,” Nessel says in a press release.

The east segment of Line 5 will remain shut down, Enbridge says, as the company works with PHMSA to ensure the safety assessments are complete and data provided prior to its restarting.

Enbridge says it is committed to sharing the information with state officials to keep it informed regarding inspections of the east segment.

“We remain willing to work with the state going forward to address issues of concern about the safety of Line 5 and its ultimate replacement with The Great Lakes Tunnel that will contain a new section of pipeline,” the company says. “Enbridge is currently seeking permit approval of the tunnel which, upon completion, will make a safe pipeline even safer.”

Featured image of the Mackinac Bridge: JamesBrey/iStock / Getty Images Plus/Getty Images

About the Author:

Brian Richesson is the editor in chief of LP Gas Magazine. Contact him at or 216-706-3748.

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