Michigan attorney general calls for shutdown of oil pipeline under Straits of Mackinac

Michigan Attorney General Bill Schuette said Thursday it’s time to begin the process of shutting down the twin 64-year-old oil pipelines that run across the bottom of the picturesque Straits of Mackinac.

The announcement came after the Republican reviewed a new study funded by the pipeline owner but overseen by the state of Michigan that examines alternative ways to deliver the nearly 23 million gallons of Canadian crude and propane that the lines carry each day. That study, more than a year in the making, claimed the pipelines could continue to operate indefinitely.

“The Attorney General strongly disagrees,” states a Thursday news release from Schuette’s office.

“A specific and definite timetable to close (the pipelines) under the Straits should be established.”

The news was welcomed by conservationists who worry that the aged “Line 5” is a threat to the entire Great Lakes basin, home to 20 percent of the world’s surface freshwater.

“The Mackinac Straits oil pipeline poses an unreasonable and existential risk to the Great Lakes and clearly cannot operate forever,” said Mike Shriberg, Great Lakes regional executive director for the National Wildlife Federation. 

One option Schuette said he would consider is a new pipeline system that tunnels under the Straits, which are the waters that connect Lakes Michigan and Huron and home to some of the most wicked currents in all the Great Lakes. 

Unlike the controversial Dakota Access Pipeline that crosses approximately 100 feet below the Missouri River bottom in North Dakota, the twin Mackinac pipelines are not buried. They lie exposed — to shipping mishaps, quagga mussel clustering and the currents ripping through the Straits.

The lines, operated by a subsidiary of Canadian pipeline giant Enbridge, Inc., carry Canadian crude, but also a significant amount of propane that heats homes in Michigan’s Upper Peninsula. Some of the crude is delivered to a U.S. refinery in the Detroit area, but much of the oil runs back into Canada, where it is refined or potentially shipped overseas.

Exactly where the oil and gas in Line 5 flows is difficult to ascertain, even for Michigan’s political leaders.

 “I’ll be honest with you, (they) haven’t been forthcoming,” Michigan Senator Gary Peters, a Democrat and pipeline critic, said of Enbridge in a June radio interview with Michigan’s WDET.

But Peters said he has learned enough to believe that “most of the oil that goes through that pipe ... is Canadian oil that goes to Canadian refineries from the West Coast to the East Coast. We’re just the transfer point through Michigan.”

Schuette acknowledges the value of the products the Line 5 system delivers to Michigan, but said it should not trump the health of the world’s largest freshwater system.

“The safety and security of our Great Lakes is etched in the DNA of every Michigan resident, and the final decision on Line 5 needs to include a discussion with those that rely on propane for heating their homes, and depend on the pipeline for employment,” Schuette said in the news release. “One thing is certain: the next steps we take should be for the long term protection of the Great Lakes.”  

The pipelines have been in the crosshairs of environmental groups and Michigan politicians from both parties since the 2010 spill on a separate Enbridge-owned line into a tributary of the Kalamazoo River in southwestern Michigan. That was the worst inland oil spill in U.S. history, unleashing 1.2 million gallons of Canadian tar sands crude into a Lake Michigan tributary. The cleanup lasted years and cost more than $1 billion.

That pipeline, constructed in the 1960s, has since been replaced.

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The twin Mackinac pipelines, part of the Line 5 route that runs 645 miles from Superior, Wis., through Michigan and into Sarnia, Ontario, were constructed in 1953. Line 5 is a single pipeline for most of the route, but it forks into two smaller lines at the approximately 4 mile-wide Straits crossing. 

The worry is if either one of those underwater pipes suffered a leak it could expose hundreds of miles of Great Lakes shoreline to oil slicks because of the volume of water that moves through the Straits — the equivalent of some 10 Niagara Falls — and the fact that the current can flow either east or west, depending on winds and other weather conditions.

One prominent hydrodynamics expert from the University of Michigan calls the Straits  the “worst possible place” in all the Great Lakes for an oil spill.

The alternative route study was one of two Line 5 reports that the state of Michigan ordered last year and that were supposed to be released this summer. A separate study looking at the economic risk of a spill in the Straits hit a snag earlier this month after the state of Michigan learned that one of the people working for the firm doing the study also worked on a project for Enbridge — a violation of the conflict of interest terms in the state’s contract with the firm doing the study.

“The evaluations of Line 5 were supposed to be independent, not tainted by outside opinions or information,” Schuette said in a statement last week. “But that’s not what happened. Instead, our trust was violated and we now find ourselves without a key piece needed to fully evaluate the financial risks associated with the pipeline that runs through our Great Lakes, this is unacceptable.”

An Enbridge spokesperson said Thursday morning corporate officials were still digesting the release of the alternative delivery report, but that the company has no plans to shut down the lines.

“Enbridge remains committed to protecting the Great Lakes and meeting the energy needs of Michigan through the safe operation of Line 5,” the statement said. “We have never wavered from that commitment. That’s our focus, day in day out.”

Enbridge has long maintained that its meticulous maintenance program means the pipelines can continue to operate indefinitely, like the nearby Straits-spanning Mackinac Bridge that opened the same decade as the pipelines.

But there is evidence that suggests the company has not always tended to the pipelines with the rigor required by its state of Michigan permit to cross the publicly owned lake bottom.

It turns out the pipelines operated for years well beyond the state’s permit that forbids unsupported spans of more than 75 feet across the undulating lake bottom.

The 75-foot limit was intended to keep the nearly inch-thick pipes from suffering metal fatigue caused by sagging under their own weight and from being stressed by the ever-changing currents ripping through the Straits of Mackinac.

In the first decade of their operation there were no apparent violations of that 75-foot limit, but work began in the mid 1970s to fortify the lines with man-made supports after the Straits' currents began to erode the lake bottom across which the pipes are laid. Pipeline operators initially fixed the emerging gaps on the lake bottom by propping the lines up with sacks of cement-like grout. Eventually engineers began using giant screws drilled into the lakebed that support brackets to cradle the pipes.

The pipeline operators contend that these supports were just conservative maintenance projects, and that their own engineering studies showed the lines were safe even if they were left unsupported for spans up to 140 feet. 

But it was not until this summer that the public became aware that over a decade ago the pipes had for a time been left unsupported at distances far greater than that. 

As part of its settlement with the federal government following the 2010 spill in lower Michigan, Enbridge agreed to do a safety analysis of other lines in its vast U.S. network. And part of that analysis involved a historical assessment of the span problem on Line 5. 

That report was completed in 2016, though it was based on investigations done over a decade ago. It revealed that a survey done around 2003 showed there were 16 spans on the lines that exceeded the company’s own 140-foot safety figure. The longest on the eastern pipe was 224 feet. The longest on the western pipe was 286 feet. Those spans have since been remedied with the installation of additional supports. 

The report further revealed that Enbridge had apparently decided on its own not to follow the state of Michigan’s requirement of no spans greater than 75 feet. As that report states: “A span of 140 ft was established by Enbridge as a criterion for taking corrective action.”

Yet another study required by the settlement over the 2010 spill required Enbridge to study the impact that clustering invasive mussels and other aquatic creatures could have on the line. That report, finished in September 2016, made mention of 19 areas on the two pipes where underwater video footage showed protective “coating delamination” on the pipe. The worry is that exposed pipeline will corrode, a leading cause of pipeline ruptures. 

Schuette demanded answers from Enbridge earlier this year about the delaminated sections and the company acknowledged 18 areas where “the pipelines’ outer wrap appeared to have anomalies,” though the company said no video footage appears to show exposed metal and that more studies are needed.

That work is under way. 

Enbridge, meanwhile, recently completed a pressure test on the Mackinac pipes by emptying the oil and putting water into them and cranking up the internal pressure to 1,200 pounds per square inch, well above its normal operating pressure of about 150 pounds per square inch.

The company announced earlier this month that those tests were a success, and that they are evidence that the lines remain fit for service. 

“The hydrotest is an industry and regulatory way of confirming that our past maintenance and inspection programs were and will continue to be effective in keeping Line 5 operating safely and reliably into the future,” the company said in a statement. 

Schuette’s office had a different take in its news release Thursday: “Nothing lasts forever.” 

Dan Egan is the Brico Fund Senior Water Policy Fellow in Great Lakes Journalism at the University of Wisconsin-Milwaukee School of Freshwater Science. In this role, he will report on pressing issues facing the Great Lakes. Editorial content is controlled by Egan and Journal Sentinel editors.