BELFIELD, N.D. – The Belle Fourche Pipeline system that contaminated a tributary of the Little Missouri River is in a landslide-prone area and vulnerable to future spills, federal pipeline regulators say.
A document from the Pipeline and Hazardous Materials Safety Administration shows that regulators believe the pipeline company may have experienced other spills in southwest North Dakota that went undetected due to inadequate leak detection monitoring and unstable terrain.
The agency issued a corrective action order to Belle Fourche Pipeline Co., part of True Companies of Wyoming, following the spill discovered Dec. 5 by a landowner northwest of Belfield.
The spill, now estimated to beat 529,830 gallons, three times larger than an earlier estimate and one of the most significant in North Dakota history, contaminated about 5 miles of Ash Coulee Creek, which flows into the Little Missouri River.
The cause of the spill is under investigation, but the company points to the slumping of a hillside in the rugged Badlands terrain where the pipeline break occurred.
Belle Fourche Pipeline Co. contested the corrective measures ordered by regulators and argued the spill was an “isolated, unpredictable event,” the document shows.
However, after holding a hearing, the federal pipeline agency concluded the pipeline system is potentially hazardous to life, property or the environment unless additional steps are taken, according to a document made public this week.
Wendy Owen, a spokeswoman for True Companies, said the company believes the pipeline leak began on Dec. 1.
The company noticed an imbalance with the pipeline on Dec. 3, but misinterpreted its own data, allowing the spill to continue unabated until a landowner discovered it two days later, according to the PHMSA order.
The Office of Pipeline Safety, part of PHMSA, argued there is a risk of repeat failure on the pipeline system due to the the topography of the area, soil conditions and slope stability issues.
Federal regulators say significant questions remain about the cause of the pipeline failure and they upheld most of the corrective action items, including requiring the company to excavate and analyze the failed section of pipe and submit a root cause failure analysis.
Regulators also ordered geotechnical evaluation of pipeline segments and a risk assessment of steep slope areas to determine if land movement could damage the pipeline.
Belle Fourche Pipeline wrote in its response to PHMSA that the company has cooperated with regulators and is “working diligently to address its impact on the environment.”
Owen said this week the company has fixed an issue that affected leak detection and officials don’t believe the pipeline system is at risk.
“We believe the ground movement is the likely cause of the pipeline rupture,” Owen said. “While it is impossible to predict landslides, we have conducted integrity testing that indicates the active portion of the line is structurally sound.”
The segment of the pipeline that failed was shut down and can’t be restarted until federal regulators give the OK. The pipeline system was built in the 1980s, but it’s believed a portion of the line near the failure was replaced in 2013, according to PHMSA documents.
The North Dakota Oil and Gas Division also is investigating the spill and analyzing potential landslide areas in the state to identify other pipelines that could be at risk.
The North Dakota Department of Health has issued a notice to the pipeline company alleging violations of water quality standards and other state regulations. The agency has not yet decided on a fine.
The spill did not affect any drinking water sources for humans, but a rancher reported losing cows that he attributes to the contamination of the creek, according to the health department.
Bill Suess, spill investigation program manager, said he had been informed that the landowner declined to have a veterinarian confirm the cause of death of the animals. However, Suess clarified this week that the landowner said no one asked him to have the animals tested.
The landowner has not returned calls from Forum News Service seeking comment.
True Companies of Wyoming also was responsible for the January 2015 Bridger Pipeline spill that involved 30,000 gallons of oil in the Yellowstone River, contaminating the drinking supply for the city of Glendive, Mont.