An independent report conducted by Hurst Metallurgical Research Laboratory Inc. faults manufacturing defects on the Pegasus Pipeline that ruptured and spewed 150,000 gallons of crude oil in Mayflower, AR, Exxon Mobil Corp. said.
Cracks were found near a seam that opened on the ruptured pipeline, according to an article in Rigzone. The report was provided to ExxonMobil and US Department of Transportation Pipeline and Hazardous Materials Safety Administration (PHMSA), which both declined to release copies of it.
The defects identified in the report reflect the “root cause of the failure,” the ExxonMobil said. Ongoing tests are being conducted to evaluate other factors in the spill that evacuated 20 families from their homes. The company said the the pipeline is shut-in.
“The cleanup is progressing well and restoration is complete in many affected areas,” ExxonMobil said on its website. “More than half of the evacuated homes have now completed the re-entry process, and the others are in various stages of completion.”
ExxonMobil noted that corrosion wasn’t a contributing factor to the oil spill.
“Based on the metallurgical analysis, the independent laboratory concluded the root cause of the failure can be attributed to original manufacturing defects — namely hook cracks near the seam,” ExxonMobil said. “Additional contributing factors include atypical pipe properties, such as extremely low-impact toughness and elongation properties across the seam.”
“We are still conducting supplemental testing, which will help us understand all factors associated with the pipe failure and allow for the verification of the integrity of the Pegasus Pipeline. These tests will help us determine the mitigation steps we need to take to ensure a similar incident does not occur again,” ExxonMobil added.