Enbridge's successful high-pressure water test of one of its twin oil pipelines in the Straits of Mackinac indicates "the underwater pipe appears to be robust," according to an independent pipeline consultant who has blasted the company's pipeline safety in the past.
But the weekend safety test doesn't alleviate the concerns of some who think a potential oil spill in one of the most dynamic areas of the Great Lakes is too much of a risk to allow the 64-year-old, underwater pipelines to continue to operate.
Enbridge conducted a hydrostatic test on the west leg of its twin, 20-inch underwater pipelines, known as Line 5, on Saturday. The test involved clearing the pipe of the crude oil and natural gas liquids it typically moves; and then pressurizing the pipe with water inside it to 1,200 pounds per square inch — double its maximum operating pressure — for four hours, followed by another four hours at 700 pounds per square inch.
No leaks, stresses, corrosion or cracking in the pipe were discovered during the testing, said Ryan Duffy, spokesman for the Canadian oil transport giant.
"The hydrotest is an industry and regulatory accepted way of confirming that our past maintenance and inspection programs were and will continue to be effective in keeping Line 5 operating safely into the future," Duffy said.
Getting through the hydrostatic test with no issues indicates "you (can) have a high degree of confidence that the pipeline has decent integrity," said Richard Kuprewicz, president of Accufacts, a Redmond, Wash.-based pipeline consulting company.
Kuprewicz, who has been critical of Enbridge in the past, has more than 40 years of experience in the oil and gas pipeline industry. He is a certified safety management engineer with a special focus on proper design and operation of oil and gas pipelines in environmentally sensitive or densely populated areas.
Kuprewicz has on multiple occasions provided analysis on pipelines on behalf of concerned nonprofit environmental groups. And he has been highly critical of Enbridge in the past, concluding in a 2013 safety analysis of the company's oil pipeline project between Hamilton, Ontario, and Montreal that there was a "high risk the pipeline will rupture."
According to the U.S. Pipeline and Hazardous Materials Safety Administration, the federal government's pipeline regulator, hydrostatic testing of hazardous liquid pipelines requires testing to at least 125% of the pipe's maximum operating pressure for at least four continuous hours, with an additional four hours of pressure of at least 110% of maximum pressure if, like the Straits pipelines, the pipes are not visible. Enbridge's test Saturday exceeded those parameters.
Line 5 moves up to 23 million gallons per day of crude oil and liquid natural gas through the Upper Peninsula before splitting at the Straits into the twin underwater pipes for the more than 4-mile stretch between the Upper and Lower peninsulas. It then reunites into a single transmission line to move the products south through the state before reaching a hub in Sarnia, Ontario.
In the Straits, Line 5's normal daily operating pressure is 150 pounds per square inch, Duffy said.
There are things that a hydrostatic test can't tell you, Kuprewicz said.
"Hydrotests don't really test girth welds that hold pipe segments together," he said. "They will use other records to (assess) that. It also doesn't tell you about pinhole leaks."
The hydrostatic testing of Line 5 was required of Enbridge in its consent decree with the federal government over a July 2010 oil spill in Marshall, Mich., and another spill that year in Illinois.
In the Marshall spill — the worst inland oil spill in U.S. history — a burst Enbridge oil transmission line spilled up to 1 million gallons of heavy crude oil into Talmadge Creek and the Kalamazoo River, necessitating a more than four-year, $1-billion cleanup of more than 38 miles of river and banks.
Enbridge was also required to pay a $62-million federal penalty, another $5 million in reimbursement to federal agencies above the $58 million it had already paid, and another $110 million in required inspection and infrastructure improvements to the company's oil and gas transmission system.
It's that Marshall spill that keeps many concerned about Line 5's risks, along with recent revelations that the underwater Straits pipelines are losing their protective coating in a number of areas, and that previously undisclosed Enbridge inspections in 2003 found long spans of the pipeline improperly supported on the lake bottom, subjecting them to flexing from the turbulent currents of the Straits.
"They can run water through the pipeline as much as they want; it doesn't take away the concern about the pipeline's safety from the things that have come out recently," said Sean McBrearty, a program organizer with the environmental nonprofit Clean Water Action based in Lansing.
The Great Lakes are a public trust that state Attorney General Bill Schuette and Gov. Rick Snyder have a duty to protect, McBrearty said. And they already have enough information to support shutting down Line 5, he said.
"It's a corporation that can't be trusted; it's a pipe we know can't be relied upon, and the water test should not have any bearing on the decision-making about whether to shut down this pipeline," he said.
The state Pipeline Safety Advisory Board, appointed by Snyder, is awaiting reports from contracted studies looking at the worst-case scenarios of a Straits oil spill, and analyzing what alternatives exist to shipping oil and natural gas liquids without using the underwater pipelines.
Enbridge will conduct similar hydrostatic testing on the east leg of its twin pipes as soon as the end of this week, depending on water and weather conditions, Duffy said.
© 2017 Detroit Free Press