LINCOLN — Two pipelines involved in a weekend petroleum spill in southeast Nebraska likely were buried at least 3 feet deep when constructed, but soil erosion over the decades might have reduced the depth.
A bulldozer operator pulling a ripper attachment through the soil damaged the pipelines Saturday southwest of Nemaha. The breaks spilled about 2,834 barrels of gasoline, diesel and jet fuel, less than half of the 6,000 barrels estimated immediately after the spill, said Bruce Heine, a spokesman for Magellan Midstream Partners, the Tulsa, Okla., owner of the pipelines.
The spill could have been prevented had the farmer operating the bulldozer called the digger's hot line before he started removing trees and brush, Heine said. State law requires such a phone call so underground infrastructure can be properly marked and avoided.
But Heine has declined to reveal how deep the damaged pipes were buried, saying that information is part of an ongoing investigation.
“Magellan uses stringent management practices, highly technical tools and other devices to protect the integrity of our pipeline system,” Heine said Tuesday in an email to The World-Herald. “When a pipeline is properly maintained and protected, it can have an unlimited life.”
Regulations from the Pipeline and Hazardous Materials Safety Administration cover all interstate pipelines in Nebraska, such as the Magellan lines, which carry fuels from Texas to Omaha, Lincoln and Doniphan.
The federal agency sets the 3-foot minimum depth requirement to protect pipelines from farm cultivation, said Damon Hill, a spokesman for the administration. Pipelines must be buried deeper when passing beneath a river.
The Magellan pipelines, mostly built around 1950, predate the federal regulations by about two decades. Still, pipeline construction crews most likely would have buried the pipeline 3 feet or maybe 4 feet deep to avoid problems with Nebraska's frost line, said William Sydow, director of the Nebraska Oil and Gas Conservation Commission.
While the pipelines now fall under federal safety regulations, those regulations say nothing about maintaining depth of cover soil, said Carl Weimer, director of Pipeline Safety Trust, a Bellingham, Wash., nonprofit that promotes pipeline safety and education.
“There can be erosion,” he said. “I've seen cases where they are right at the surface.”
A lack of depth was a factor in last summer's spill of 1,000 barrels of oil into the Yellowstone River in Montana. The Exxon Mobil pipeline, buried as shallow as 5 feet in some places, was damaged by flood-related river scouring.
Pipeline depth also has been an issue surrounding the proposed Keystone XL pipeline, which would carry crude oil from Canada's tar sands region to refineries on the U.S. Gulf Coast. TransCanada, the pipeline sponsor, plans to bury the Keystone XL at least 4 feet deep, said Shawn Howard, a company spokesman.
TransCanada used the same 4-foot minimum depth when it constructed the first Keystone pipeline through Nebraska in 2009, Howard said.
Meanwhile, state officials were pleased Tuesday to learn the Magellan spill wasn't as bad as first thought.
“It wasn't unexpected,” said Jim Bunstock, a spokesman for the Nebraska Department of Environmental Quality. “They had stated from the start they were being very cautious with their estimate.”
The company always tries to avoid underestimating a spill early on, Heine said.
After crews completed repairs on the pipelines Monday, they re-pressurized the lines and metered the volume of fuel required to refill them. That, coupled with the fuels recovered at the site, allowed company officials to calculate a more accurate volume of the spill.
The spill involved 650 barrels of diesel, 655 barrels of jet fuel and 1,529 barrels of gasoline — or a total of 119,028 gallons.
It's the largest pipeline spill in Nebraska since nearly 5,000 barrels escaped from the Platte Pipeline in 1996 near Lawrence.
No one was injured in the Magellan spill, and no nearby homes were evacuated.
Most of the fuels soaked into a crop field, but some drained into an unnamed creek that is a tributary to the Little Nemaha River.
Cleanup crews made up of company employees and contractors will remain on site, and state environmental workers will continue to monitor the creek. They also will take core samples from the soil to track contamination. Groundwater supplies are not believed to be threatened, Bunstock said.
After the contamination is contained and cleaned up, the incident will be reviewed by the Department of Environmental Quality's legal staff for possible fines.
Contact the writer:
402-473-9587, joe.duggan@owh.com
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