Canadian oil transport giant Enbridge knew a section of the required protective coating on its twin, underwater oil pipelines in the Straits of Mackinac was damaged in 2014 — but did not make state officials aware of it until this August.

The revelation further fuels controversy about the pipelines, with critics saying that the continuing to ship 23 million gallons of crude oil and natural gas liquids through the 64-year-old Line 5 is too great of a risk to the Great Lakes and shoreline communities.

And it signals an even further deterioration of trust between state regulators and Enbridge.

“We are deeply disappointed that Enbridge did not tell the Pipeline Safety Advisory Board in March the whole story about Line 5 coating deficiencies," said Valerie Brader, executive director of Michigan Agency on Energy and co-chair of the Pipeline Safety Advisory Board, in a statement.

"Enbridge owes the people of Michigan, the Advisory Board and the State an apology. This issue is too important to the people of Michigan to not tell the truth in a timely manner, and right now any trust we had in Enbridge has been seriously eroded."

Enbridge spokesman Ryan Duffy in late August described areas of exposed bare metal on the underwater pipes as "Band-Aid sized." But inspection reports Enbridge shared with the state in September, in response to requests for more information about the lost coating, show eight areas on the twin lines where bare metal is exposed to the elements. All but one measures 7 inches or more in diameter.

The missing enamel coating was discovered during pipeline inspections required in a 2016 consent decree between Enbridge and the federal government, part of a settlement stemming from a massive oil spill from an Enbridge oil transmission line near Marshall, Mich., in July 2010 that fouled more than 35 miles of the Kalamazoo River and prompted a four-year cleanup that cost more than $1 billion. Enbridge was fined $61 million as part of an overall $177-million settlement that required improvements to its pipeline networks.

The protective coating is required on the pipeline as part of a 1953 easement between Enbridge and the state of Michigan, allowing the pipelines on the Straits bottom lands.

State officials on Friday announced Enbridge possessed information about the damage to at least one area of pipeline coating in 2014 and failed to disclose it to state agencies. The coating damage occurred when Enbridge was installing required anchors meant to better secure the pipeline to the lake bottom.

Duffy, in an emailed statement Friday, said engineers in Enbridge’s pipeline integrity department have been aware of the coating damage since it occurred in 2014 and continued to monitor affected areas.

"The coating damage was determined not to present any threat to the safety of the pipeline at any time," he said.

When Enbridge officials in March told the state Pipeline Safety Advisory Board that the company was not aware of any areas of bare metal on the Straits pipelines, those "statements were accurate to the best of their awareness," Duffy said. He called the failure of some Enbridge officials to know what some company engineers knew "an internal reporting issue."

State Attorney General Bill Schuette, in a statement, blasted the disclosure about the missing pipeline coating.

"This latest revelation by Enbridge means that the faith and trust Michigan has placed in Enbridge has reached an even lower level," he said. "Enbridge needs to do more than apologize, Enbridge owes the citizens of Michigan a full and complete explanation of why they failed to truthfully report the status of the pipeline.”

The Michigan Department of Environmental Quality is considering an Enbridge permit to install 22 additional anchor supports on the underwater pipeline, as missing supports have created gaps beyond what's allowed in the easement with the state.

"The DEQ is going to take this revelation very seriously and will conduct a thorough assessment of the information to consider during our continued review of the permit application,” said agency Director C. Heidi Grether in a statement Friday.

Enbridge vows to change how it shares what it knows, Duffy said.

"As our dialogue with the state continues, Enbridge has come to recognize that issues which do not present a threat to the safety of the pipeline can still present a strong concern to Michigan, and we are adjusting our communication approach accordingly," he said.

"We regret that this miscommunication may have caused confusion for state officials and the public. We are committed to being transparent on all matters related to the safe operations of our pipelines in Michigan."

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