Inside Climate News, the prize-winning news outlet that we partnered with on reporting on the ExxonMobil pipeline break at Mayflower, has new reporting today based on FOI-produced documents that raise questions about the adequacy of testing aimed at assuring the safety of restarting the northern portion of the line.
ExxonMobil could restart the northern leg of its Pegasus oil pipeline within a year, but the company’s pre-startup tests could leave behind threats large enough to endanger the public, according to a review of Exxon’s proposal.
Those details and others are laid out in Exxon’s repair plan for the Pegasus northern segment, a document that was submitted to federal pipeline regulators at the end of March. The so-called “integrity verification and remedial work plan” was not publicly released, but InsideClimate News obtained a copy through a public records request.
Exxon plans to conduct stress tests on the pipeline to prove that it can be safely restarted. But the company also said if high-pressure tests trigger a significant number of pipeline failures, it might lower the pressures—a downgrade that could leave dangerous cracks in the pipe. The Pegasus split apart in Mayflower, Ark. in March 2013, and sent a flood of Canadian diluted bitumen into a neighborhood.
A pipeline safety expert says Exxon’s testing approach is flawed, though he favors hydrotesting. He said some portions of the line could be tested below adequate pressures. Another unnamed expert shared those concerns, but said he lacked sufficient information to make a fully informed opinion about the sufficiency of testing.
A federal agency is currently reviewing the testing plan. If regulators are satisfied, they could approve a restart of the line before completion of year-long analysis of all tests.