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State Questions Enbridge on Coating Gaps

Wednesday, September 20, 2017

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Michigan officials appear to be growing impatient with Canadian energy firm Enbridge Energy after they say the company downplayed the size of gaps in the protective coating on its Line 5 liquids pipeline under the Straits of Mackinac.

Initial reports from Enbridge said that there were two small areas of coating loss on the twin underwater pipelines, plus a third spot that merited further investigation; the company said the gaps were likely caused by anchoring work done on the pipeline. The company referred to one coating gap as being the size of “a Band-Aid.”

Mackinac Straits
ElementBroccoli, CC BY-SA 4.0, via Wikimedia Commons

Enbridge's Line 5, which runs under the Straits of Mackinac in Michigan, has at least five areas of coating loss, two of which are at least one square foot in area.

Now, local media are reporting that Enbridge has told state officials there are five areas of coating loss, and two are at least one square foot in area. According to The Detroit News, Michigan Department of Environmental Quality Director Heidi Grether said at a public meeting Monday that the company was untruthful with the state in its original statement on the matter.

“This troubled us greatly when we learned about this,” Grether said, according to the newspaper. “And frankly I think that we really need to know that what Enbridge is telling us is the truth and that it is accurate because we were not told the truth nor was it really accurate.”

Enbridge officials have held that the identification and subsequent repair to the coating gaps shows that its process it working correctly.

“There is no safety issue—there is no metal loss, no corrosion in these areas,” Enbridge spokesperson Ryan Duffy said at Monday’s pipeline-safety meeting, according to the Detroit Free Press. “And now we’re going to start the coating repairs. We’re ready to go; we have the barges, the divers, in the Straits, ready to start the repairs.”

Risk Assessment Head Named

At the same meeting, the state’s pipeline safety panel voted to have Guy Meadows, a member of the panel, oversee a team of independent researchers who will put together a risk analysis of Line 5. The local press quickly noted that Meadows, director of the Great Lakes Research Center, at Michigan Technological University, has worked for Enbridge in the past.

Earlier this year, a risk assessment for the pipeline was cancelled by the state when officials discovered that an employee of the inspection contractor, Det Norske Veritas, had taken a contract job with Enbridge.

Pipeline Under Fire

The 64-year-old Line 5, which conveys crude oil and natural gas liquids from Alberta to Sarnia, Ontario, crossing through Michigan en route, has never experienced a leak. But the aging pipeline has come under fire from environmentalists, residents and state officials in recent years, especially after the 2010 rupture of Enbridge’s Line 6B, which released more than 843,000 gallons of oil, much of it into the Kalamazoo River.

Line 5 map

Line 5 carries crude oil and natural gas liquids from Alberta to Sarnia, Ontario, supplying 65 percent of the propane used on Michigan's Upper Peninsula on the way.

Earlier this year, a state lawmaker proposed legislation that would require a third-party assessment of the pipeline, and would shut it down if the assessment determined there was sufficient risk. In July, an assessment performed by Dynamic Risk Assessments Inc. held that there was no indication of coating delamination on the pipeline.

Enbridge has held, and Dynamic Risk Assessments agreed, that the coating on the 193 pipeline is coal tar enamel. A report authored by engineer Edward Timm and released by the National Wildlife Federation called that assumption into question earlier this year, though.

Timm said in his report that while coal tar enamel was called for in the order for the pipeline, it’s not clear that that’s what was ultimately used to coat the pipe. Timm concluded it’s more likely it was “a solvent-based asphalt primer, two layers of asphalt-saturated glass fiber fabric and a white protective overlayer of white craft paper bonded with asphalt enamel.”

In June, the pipeline passed a pressure test in which it was subjected to pressures of 1,200 psi, eight times its normal operating pressure.

In addition to crude oil destined for Sarnia, Enbridge says Line 5 supplies 65 percent of the propane used on Michigan’s Upper Peninsula.


Tagged categories: Coating failure; Government; NA; North America; Oil and Gas; Pipeline; Quality Control

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