The U.S. Pipeline and Hazardous Materials SafetyAdministration has issued a corrective action order to in response to theApril 29 Texas Eastern TransmissionLP pipeline explosion.
The order directed Spectra to leave the exploded pipe — Line27 — and three other lines operating in its vicinity shut down until theincident and the conditions of the pipelines are more thoroughly investigated.
While the accident cause remains unclear at this time, thepreliminary investigation found evidence of corrosion along two of the line'scircumferential welds: one at the point of failure and another excavated afterPHMSA's response to the incident, according to the agency. PHMSA said that thecorrosion pattern could indicate that there was a flaw in the coating materialapplied to certain weld joints when the segment was being constructed.
The agency ordered the operator to expose significantsections of the affected and neighboring pipe and evaluate the segments. Whenthe company is able to return them to operation, PHMSA directed Spectra torestart them at low pressures.
PHMSA also demanded to see the results of in-lineinspections that had been done on Line 27 in 2005 and 2012, along with anyrelevant analysis. According to the company, the 2012 in-line inspectionrevealed no areas requiring repair or remediation before the next inspection.
"This explosion was devastating," PHMSAAdministrator Marie Therese Dominguez said May 4 in an emailed statement "Wehave directed the operator to take several immediate actions to determine theroot cause of the failure, and to ensure the integrity of three nearbypipelines before they can be restarted."
The Delmont, Pa., rupture ejected from the ground about 24.5feet of 30-inch pipe, which landed about 100 feet away. The explosion and firecreated a crater that was roughly 30 feet wide, 50 feet long and 12 feet deep,accompanied by a burn zone with a quarter-mile radius.
The incident sent one local resident to the hospital withthird-degree burns over 75% of his body.