Alyeska Pipeline Service Co. has signed a consent agreement with the U.S. Department of Transportation’s Pipeline and Hazardous Materials Safety Administration that resolves the notice of proposed safety order PHMSA issued Feb. 1.
PHMSA issued its Feb. 1 notice after an oil leak at Pump Station 1 on Alaska’s North Slope. The leak, discovered Jan. 8 in the basement of a booster pump building, forced two shutdowns of the pipeline, the longer one lasting about 84 hours.
The spill, which resulted in no oil escaping the building, was attributed to internal corrosion in some station piping. The mainline 48-inch pipe was not involved. PHMSA said it conducted an investigation of the Pump Station 1 leak and, more broadly, of the “safe operation” of the pipeline system.
“As a result of the investigation, it appears that multiple conditions exist on your pipeline facility that pose a pipeline integrity risk to public safety, property or the environment,” the notice to Alyeska said.
The notice focused on the pipeline’s declining throughput and the implications low flow has for pipeline safety, particularly during a winter shutdown.
PHMSA expressed concerns about crude oil cooling and water freezing inside the pipeline, about potential corrosion in inaccessible piping and about Alyeska’s “cold restart” procedures and equipment. PHMSA proposed a list of “corrective measures,” many incorporated in the consent agreement.
Under the agreement, the company makes numerous work commitments such as:
• Alyeska will replace or remove oil piping that can’t be inspected with inline tools or some other PHMSA-approved method.
• Alyeska will install an additional pig launcher and receiver on the pipeline between pump stations 5 and 10.
• Alyeska will study the need for increased tank capacity at pump stations as a way to “mitigate the consequences of a cold weather shutdown.”
• Alyeska will submit a revised cold restart plan to PHMSA and pre-position certain equipment during winter.