Canadian oil company TC Energy said Thursday that faulty welding caused an “instantaneous rupture” in its Keystone pipeline that gushed hundreds of thousands of gallons of extra sticky tar sands crude oil onto Kansas native prairie, cropland and into a creek.
Meanwhile, the pipeline operator now estimates less oil escaped than originally thought. And it revealed that it expects the cleanup and investigation will cost about $480 million.
Investigation into the spill
The federal government required TC Energy to have a third party conduct metallurgy tests. TC Energy says it can’t make the full report public. The Kansas News Service has filed an open records request to the federal government seeking the full document.
TC Energy also gets three months to complete an analysis of the cause of the spill. That report must be “supplemented or facilitated by” a third party. The analysis isn’t finished, but TC Energy said in an online post early Thursday that the mechanical and metallurgy results had come back.
It says those tests point to factors including “bending stress on the pipe and a weld flaw.”
TC Energy seemed to point a finger outside its own ranks, saying the weld flaw was made at a “fabrication facility.”
“The weld flaw led to a crack that propagated over time as a result of bending stress fatigue, eventually leading to an instantaneous rupture,” TC Energy wrote in its press release. “The cause of the bending stress remains under investigation.”
The company said welding inspection and testing had complied with “applicable codes and standards.”
It also said the pipe itself showed no defects.
And it said the Keystone was operating at a legal pressure level when it burst.
The Kansas News Service submitted an open records request in December for a report that shows the precise pressure levels at the time of the rupture.
In late December, the federal government allowed TC Energy to restart the pipeline, on the condition that it operate for the time being at a lower pressure than when the rupture occurred.
“Our focus continues to be the safe operation of the pipeline system,” TC Energy wrote in its press release.
The federal government is also requiring TC Energy to look for other potential weak points within the 96-mile stretch of the Keystone system that includes the site of the spill in Washington County near the Nebraska border.
That stretch runs from Jefferson County in Nebraska through Washington, Clay and Dickinson counties in Kansas.
Oil volume estimates and cleanup
TC Energy now says it believes less oil spilled out of the Keystone than its original estimate of 588,000 gallons.
The new estimate is about 543,000 gallons, the bulk of which has been recovered.
It says the new figure is based on the volume of crude oil that the company injected to refill the pipeline when restarting it.
As for cost, the company said cleaning and remediating the area and investigating what happened will cost an estimated $480 million.
“This estimate may be adjusted as we continue to progress work on site,” it said. “We are working with our insurers to maximize cost recoveries.”
It’s not clear whether federal or state spending factors into this estimate. The company is required to repay some (but not all) of the public taxpayer money spent on cleaning up its mess.