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Enbridge document shows areas of Line 5 pipelines where protective coating could be missing

Part of a map of the easternmost oil and natural gas liquid pipeline that shows areas of "coating delamination." The east line shows 11 such areas. The west line shows seven.
Enbridge document submitted to the EPA
Part of a map of the easternmost oil and natural gas liquid pipeline that shows areas of "coating delamination." The east line shows 11 such areas. The west line shows seven.

An Enbridge work plan document shows areas where a protective coating around its twin oil pipelines running through Lake Michigan might be failing.

Enbridge posted the document on its website last fall. It shows 18 specific areas along the pipelines where there is “coating delamination.” The 64-year-old pipelines were installed with a coating around them to protect for corrosion.

These areas are marked specifically on a map in the document.

Click hereto see a map of the easternmost pipeline under the Straits of Mackinac.

And click herefor a map of the westernmost pipeline.

Enbridge officials say the document is a testing plan they submitted to the Environmental Protection Agency. The company was compelled to do more testing on the condition of the pipeline through a consent agreement with the EPA that was reached after the company’s massive Line 6B spill in southern Michigan. This plan outlines testing the company will do to determine whether biota, like quagga and zebra mussels, are affecting the integrity of the pipeline.

The plan calls for testing areas where the coating is intact and for testing “holiday” areas – or places where the coating has failed.

From the work plan:

This Plan proposes to provide visual surveys and collection of biotic samples from locations representative of each zone of the Dual Pipelines, while also correlating those sampling locations with the limited numbers of areas of the pipeline where there is a loss of coating around the pipe (“holidays”). Pipeline sampling locations were selected near the mid-point of each zone or proximal to a holiday area.

The report also references testing places “where bare metal is exposed.”

Ryan Duffy is a spokesman for Enbridge. He says the areas identified in the document are areas where there is “hypothetical” coating loss.

“The plan is basically saying ‘if we find this, or if we find this, you know, we’ll test in those areas,’ those kinds of things,” says Duffy. “But we have not found any issue at all with the coating on the pipe.”

Duffy reiterated what the company has been saying all along - that the protective coating is in very good condition.

Environmental groups are skeptical of this answer.

Jennifer McKay is with the Tip of the Mitt Watershed Council and is a member of Michigan’s Pipeline Safety Advisory Board. She alerted state officials earlier this week after she read the document.

“It seems like they’ve identified them to me,” says McKay.

McKay says it raises a lot of questions about what the company knows about these so-called “holiday” areas.

“When were they identified? How long ago? How long have they known about it? How many of them are there? How large are they? To what extent are we seeing coating loss? Is it just a miniscule portion, or is it actually a complete loss of coating?” asks McKay.

Mike Shriberg of the National Wildlife Federation says the language used in the report is clear.

“That doesn’t, to me, say there’s a hypothetical or a potential to that. It says ‘where there is a loss of coating,’” he says.

The Pipeline Safety Advisory Board meets next on March 13th. The company will likely be pushed to provide more details about what they know about the condition of the coating.

*Editor’s Note: Enbridge Energy is a financial supporter of Michigan Radio.

Mark Brush was the station's Digital Media Director. He succumbed to a year-long battle with glioblastoma, an aggressive brain cancer, in March 2018. He was 49 years old.
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