For a crude oil pipeline carrying 760,000 barrels a day, a “pinhole leak” is bigger than it sounds

Enbridge Line 3 could spill up to 7,600 barrels a day without triggering leak sensors

One of the difficulties writing about the proposed Enbridge Line 3 crude oil pipeline is that one gets buried by thousands of pages of documents, much more than most people have the time to read. There’s testimony, briefing papers, the environmental impact statement, administrative law judge analysis, permit applications, permit decisions, legal appeals … you get the picture.

There are many important stories hidden in these documents. I haven’t scratched the surface. I depend on people who have done the deep dive, people like Nicolette Slagle, Honor the Earth’s research director. She put me onto the “pinhole leak” story. It sounds small enough until you get into the details.

Honor the Earth and its consultant CJE did important work pointing out flaws in Enbridge’s pinhole leak analysis. Stunningly, state regulators failed to acknowledge any of them in Line 3’s final environmental impact statement.

This story is too late to affect change in the Line 3 environmental impact statemenet. But it raises larger questions about state regulators’ ability to effectively review future proposals of similar harmful projects.

File photo of pipeline protest.

Stantec, an Enbridge consultant, submitted a 50-page report on pinhole leaks in 2017 as part of the debate over Line 3’s environmental impact statement. It begins by noting: “there is no formal industry definition for a pinhole release.”

Enbridge then offers its own generic definition, calling a pinhole leak: “a slow and small leak of crude oil from the proposed pipeline … that might not be immediately detected by the leak detection systems.”

So how big could a Line 3 “pinhole” be and still avoid detection? Stantec said Line 3’s sensors would detect leaks of approximately one percent of the pipeline’s crude oil flow.

At 760,000 barrels per day — Enbridge proposed capacity for the new Line 3 — a one-percent leak equals 7,600 barrels a day (or nearly 320,000 gallons a day). (For comparison, that’s almost 36 tanker trucks of crude oil or 11 rail cars.)

At even half that rate, that’s no pinhole leak.

Honor the Earth hired CJE to critique Stantec’s analysis. This blog draws heavily on its work.

CJE’s faults Stantec’s work on many grounds. We’ll focus on three issues:

1. Enbridge’s consultant asserted unrealistic spill response times: The Stantec report says that if a one-percent leak happens — 7,600  barrels per day — Enbridge would respond and shut it down in two hours. That seems very optimistic given that the pipeline senors wouldn’t detect the leak; it would require someone to see the leak, report it, and get it shut down.

By Stantec’s analysis, a 7,600 barrel-a-day leak would get such a fast response that the total spill would be a mere 633 barrels. The CJE report says Stantec offered no studies to justify such a fast response time.

Pipeline operators typically conduct aerial or ground patrols, and cover the entire route every two weeks, Stantec said. That seem to indicate a pinhole leak could go undetected for quite some time. Stantec asserts that most pinhole leaks on the larger end, spills of 1,000 barrels or more, would occur near construction sites or maintenance facilities and workers would spot it right away.

For a scientific report, saying “most leaks” would occur near construction sites is pretty vague. How many of these larger pinhole leaks could happen in remote areas and not get detected for up to two weeks?

2. Enbridge’s consultant failed to analyze the harm done from so-called pinhole leaks: As CJE puts it, nowhere in Stantec’s 50-page report does it discuss the real life impacts of spills at specific sites, such as sensitive wetlands, fens, and peatlands.

Because Stantec’s analysis doesn’t discuss site-specific damage, “it is not an adequate assessment of the impacts of a crude oil release,” CJE wrote.

3. Enbridge’s consultant used suspect data and failed to justify it. Stantec’s report estimated how fast a Line 3 pinhole leak would rise to the surface so that it could be seen and reported. But CJE said Stantec’s numbers were pulled from an analysis done for the Keystone XL project. Stantec didn’t show that conditions along the Keystone XL route are similar to the Line 3 route. Further, Stantec doesn’t analyze the leaks of greatest concern, those in sandy soil where oil would seep into the ground more quickly, making the leak more difficult to detect.

“This combination of errors grossly underestimates the volume of crude oil that would infiltrate the soil,” CJE wrote.

State regulators ignored Honor the Earth’s critique

The Minnesota Department of Commerce wrote Line 3’s final environmental impact statement and the Minnesota Public Utilities Commission approved it. Chapter 10, the section dedicated to accidental crude oil spills, dedicated less than one page to pinhole leaks.

That discussion acknowledges in general terms that undetected pinhole leaks could result in something approaching a large spill.  “Unnoticed pinhole leaks can lead to the infiltration of crude oil … and result in contact with the water table and surficial groundwater aquifer,” it said

That sounds bad. But the environmental impact statement stops there and fails to go any deeper. A mere two sentences later, the state closes the pinhole leak discussion by vaguely dismissing the problem. Pipeline monitoring systems, it said “greatly lower the potential for long undetected releases.”

The environmental impact statement doesn’t acknowledge the problems cited by Honor the Earth’s consultant, and let’s Stentac’s analysis stand.

Comment: Enbridge’s consultants fudged numbers to benefit their client and our state regulators seem incapable of calling it out.

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