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Questions remain a year after 400,000 gallon South Dakota oil spill

Questions remain a year after 400,000 gallon South Dakota oil spill

  • Updated

The nation’s seventh-largest onshore oil or gas spill was discovered a year ago this month when the Keystone Pipeline leaked an estimated 407,400 gallons of crude oil into a field in rural Marshall County in the northeast corner of South Dakota near the North Dakota border.

The resulting problems have been mitigated, but what cracked the pipe has yet to be determined, at least with certainty.

Twelve months after the leak, Marshall County Commission Chairman Doug Medhaug realizes things could have been worse.

As bad as it was, the timing was fortuitous, and the response couldn’t have gone smoother, he said.

Medhaug said he doesn’t think the pipeline will leak again in the county.

There’s no way to know for sure, though.

“Good thing was when it happened it was cold and frozen,” Medhaug said.

Had temperatures been warmer, the melting ice and thawed ground would have made the cleanup process a lot messier and more expensive, he said.

As things were, the spill cost TransCanada $9.57 million, according to the federal Pipeline and Hazardous Materials Safety Administration.

“The roads were cold and didn’t get beat up,” Medhaug said.

He said TransCanada, the company that built and owns the pipeline, was generous when covering the damages on county roads used by the cleanup crews. The company paid the county $350,000.

The Keystone Pipeline carries crude oil more than 2,600 miles from eastern Alberta, Canada, to Oklahoma and Illinois. The pipeline passes through eastern North Dakota and South Dakota. There have been 14 leaks since it was commissioned in 2010, according to a federal spill database. Most have been fairly minor, including one in southeast South Dakota.

TransCanada deployed hundreds of workers to the scene within a day of the Marshall County leak being confirmed. Within two weeks, the pipeline had the go-ahead to start back up after a temporary stoppage.

In less than six months, the spill site was free of oil contamination and seeded — just in time for spring.

But a year after the leak, a final investigation report from the federal Pipeline and Hazardous Materials Safety Administration has yet to be released.

Gary Hanson, a state utilities commissioner, has been more critical of TransCanada than was Medhaug. He previously questioned whether the company followed the conditions required by the state permit, but admitted it would be nearly impossible to prove violations during construction.

So far, no federal or state reports have indicated that there were any violations, Kristin Edwards, a PUC attorney, said Thursday.

“We are kept informed every step of the way, even though all of the information goes to a different agency. (Because the reports are done by different agencies and sent elsewhere), I do not have any physical reports to share with you,” Edwards said.

A year after the spill, TransCanada acknowledges the problem as it did the day after.

“While we firmly believe no incident is acceptable and deeply regret that this occurred, our teams executed our emergency response and cleanup procedures effectively, in close cooperation with regulatory agencies, community members and landowners,” said Robynn Tysver, a spokeswoman for TransCanada.

“Today, the site has been cleaned. Going forward, we remain committed to achieving our goal of zero incidents and we are focused on finding ways to reach that level of performance in all areas of the organization,” Tysver added.

TransCanada has taken measures to improve control over the Keystone Pipeline’s quality. For example, it unearthed a section of the line 15 miles north of the rupture site in order to perform maintenance on its coating.

Workers also unearthed other sections of the pipeline in the area to perform similar maintenance work.

Oil started flowing through the pipeline on Nov. 28, 2017. Before Nov. 16, 2017, the pipeline had not been inspected for potential leaks or cracks using in-line tools that pass through the pipeline, according to a National Transportation Safety Board report issued in July. It notes pressure in the pipe through Marshall County increased when an inspection device passed through.

According to the safety board report, which is different than the expected Pipeline and Hazardous Materials Safety Administration report, the pipeline’s strength was compromised because it was damaged during installation in 2008. It’s suspected that happened when a metal-tracked vehicle drove over it, and it caused the pipeline to fatigue and crack over time.

The weakened section of pipeline finally gave out and ruptured around 5:33 a.m. on Nov. 16 of last year.

The field is not near a populated area, and the land was enrolled in the Conservative Reserve Program, which means the landowner did not suffer any crop losses.

The rural setting and dry weather conditions allowed TransCanada clean up crews to begin removing any contaminated soils relatively easily.

The report indicates that the pipeline’s control center, in Calgary, Alberta, noticed the pressure had increased to 1,352 pounds per square inch when the inspection device passed. The maximum pressure allowed by a state permit is 1,440 pounds per square inch.

Then, a significant decrease in pressure and an increase in the flow rate prompted a shutdown of the pipeline at 5:36 a.m., according to the report.

TransCanada officials didn’t contact local emergency officials or nearby residents about the leak for about four hours.

It wasn’t until the Trans- Canada employees confirmed the oil leak at the scene that they notified the Marshall County Sheriff’s Office. Local law enforcement arrived minutes after they were informed of the spill, which had gone unnoticed and unreported by passersby, according to the report.

The South Dakota Department of Environment and Natural Resources did not investigate the cause of the leak, but rather focused on remediation efforts, said Brian Walsh, an environmental scientist manager for the department.

“In response to the spill, DENR required TransCanada to identify and excavate the contaminated soil and properly dispose of it. The soil was disposed of at the Sawyer Landfill in North Dakota. The excavation was backfilled with clean soil, the top soil was replaced and the site was reseeded. These activities were completed in early 2018,” Walsh wrote in an email.

“In addition, DENR required TransCanada to install wells and conduct quarterly groundwater sampling to monitor the shallow groundwater for potential impacts,” he said.

Three have been completed so far and have revealed no problems, Walsh said. All contaminant levels were either nonexistent or below what is allowed by South Dakota ground water quality standards, he said. A fourth sample will be taken yet this year.

“After (we) review the results of the upcoming sampling event, DENR will determine what, if any, additional action is needed to move this case toward regulatory closure,” Walsh said.

Some state lawmakers have wanted to change pipeline regulations during legislative sessions since the leak. One bill aimed to place a moratorium on pipeline construction in South Dakota, but it was killed during a committee hearing. Walsh said he’s not aware of any ongoing efforts to change pipeline regulations.

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