Get the latest weekly fluid news direct to your inbox.

Sign up for our free newsletter now.

Pipeline behind 500,000 gallon leak still a risk according to regulators

The pipeline behind a 529,830 gallon (2.4 million litres) oil spill in 2016 is still vulnerable to leaks in the future, according to federal pipeline regulators in the US.

In December 2015 the Belle Fourche Pipeline system in North Dakota, USA, contaminated five miles of Ash Coulee Creek, which flows into the Little Missouri River. It was one of the biggest oil spills in the state’s history.

Exactly what caused the spill remains under investigation, but the pipeline operators point to slumping in the terrain where the pipeline break occurred.

According to the Bismarck Tribune, a document from the Pipeline and Hazardous Materials Safety Administration (PHMSA) 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.

After a hearing, the federal pipeline agency concluded that the pipeline system remains a hazard unless steps are taken, according to a document it has released. The Office of Pipeline Safety, part of the PHMSA, argues that the topography of the area, soil conditions and slope stability issues mean there is a risk of a repeat failure on the pipeline.

A spokesperson for the company said that the leak detection issue behind the 2016 spill had been fixed, and the pipeline was no longer at risk. “We believe the ground movement is the likely cause of the pipeline rupture,” Wendy Owen told the Bismarck Tribune. “While it is impossible to predict landslides, we have conducted integrity testing that indicates the active portion of the line is structurally sound.”

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. Although no drinking water was contaminated, a local farmer reported several of his cows were killed as a result of the spill.