Enbridge shuts down leg of Line 5’s dual Straits pipelines after discovery of anchor support damage

Enbridge has resumed normal operation of the west leg of the dual pipelines that make up the Mackinac Straits crossing portion of its Line 5 after discovering damage to an anchor support last week on the east leg.

After discovering the damage during a routine inspection on June 18, Enbridge initially shut down both legs as a precaution, reopening the west leg after further inspections found no issues with the pipeline itself. At press time this week, the east leg remains in shut down status as further assessment is being done as a matter of precaution.

As of Monday, June 22, Enbridge had completed an engineering analysis of the forces applied to the anchor support and an evaluation of the entire east pipeline for any potential damage. Remotely operated vehicle (ROV) inspections of the remainder of the east leg confirmed no damage to the remaining screw anchors and the pipeline itself.

To assure transparency and efficiency, Enbridge provided assessments on both the east and west pipeline legs to U.S. Department of Transportation’s Pipeline and Hazardous Materials Safety Administration (PHMSA) and the state of Michigan. Enbridge has stated it will not resume operation on the east leg without further discussion with the state of Michigan and approval from PHMSA.

Last weekend, the Michigan Gov. Gretchen Whitmer sent a letter to Enbridge CEO Al Monaco, requesting that the company immediately shut down the dual pipelines running through the Straits until damage is investigated, assessed and preventative measures are put in place.

On June 22, Michigan Attorney General Dana Nessel filed motions in Ingham County Circuit Court to suspend operations of Enbridge’s Line 5 pipeline until the state has conducted a full review of the information related to the incident. The Attorney General asked Court to order Enbridge to provide all of the information in its possession related to the nature, extent and causes of the newly discovered damage to Line 5. She also requested that the Court order operations of the pipeline be suspended until the state has conducted a full review of the information provided with the assistance of independent experts.

Gov. Whitmer subsequently issued a statement in support of Nessel’s actions on Line 5.

Links to the filed documents may be found at michiganoilandgas.org/blog.

In response, Enbridge said, “The temporary restraining order and preliminary injunction sought by the Attorney General of Michigan is legally unsupportable, unnecessary, and will be vigorously opposed” by the company.

“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," said Vern Yu, Enbridge executive vice president and president, liquids pipelines. "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."

The Michigan Oil and Gas Association will keep you updated as this story continues to develop.

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