The US Pipeline & Hazardous Materials Safety Administration (PHMSA) granted ExxonMobil Pipeline Co. a 90-day extension to submit a plan to repair its 20-in. OD, 848-mile Pegasus crude oil pipeline. Pegasus ruptured Mar. 29 near Mayflower, Ark., about 25 miles northwest of Little Rock, releasing an estimated 5,000 bbl.
The extension follows PHMSA’s notification last week that ExxonMobil had probably violated nine pipeline safety regulations in relation to the spill and was subject to $2.6-million in civil penalties as a result. PHMSA found ExxonMobil had failed to:
• Follow operating procedures.
• Update risk assessments.
• Take prompt action in place identified as requiring same.
• Give adequate priority to the potential for problems in high-consequence areas (HCA).
• Meet 5-year assessment intervals.
• Properly consider the risk of seam failures in pre-1970s low-frequency ERW pipe in its integrity management program.
PHMSA noted that ExxonMobil had experienced multiple hydrostatic test failures on Pegasus during first 1991 and then 2005-06. The agency said the pipe manufacturing information, fracture toughness, and hydrotesting failure history provided more than adequate information for the line to be considered susceptible to seam failure. ExxonMobil also failed to establish a 5-year reassessment interval in relation to the failed tests of 2005-06.
The largest portion of the fine ($783,300) stemmed from ExxonMobil’s failure to follow its operations and maintenance procedures by selectively using results of Threat Identification and Risk Assessment Manual (TIARA) process in 2011, resulting in failure to properly characterize the risk of a release to the Lake Maumelle watershed and other HCA in the Conway-to-Foreman segment of the pipeline. This failure set in motion a chain of events by which risk reduction activities in multiple integrity processes that rely on the TIARA results as inputs did not occur.
As part of its proposed compliance order, PHMSA called on ExxonMobil to within 30 days submit a spreadsheet identifying all pre-1970 ERW pipe operated under its integrity management (IM) plan and identify and catalogue all IM processes used in risk assessment and integrity decisions related to determining seam-failure susceptibility.
ExxonMobil said it was disappointed PHMSA had issued a Notice of Probable Violations and was cooperating with the agency in all matters related to its investigation of the Pegasus rupture.
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