PHMSA blames corrosion as possible reason for pipeline explosion

The federal Pipeline and Hazardous Materials Safety Administration (PHMSA) said a preliminary investigation into last week’s natural gas pipeline explosion in Western Pennsylvania was possibly due to corrosion.

The corrosion would indicate a possible flaw in the coating on weld joints on the Spectra Energy-operated line, Kallanish Energy learns.

The failed pipe section was sent by PHMSA to an independent metallurgist for analysis, and a third-party metallurgist contracted by Spectra also was at the blast site.

Despite its preliminary findings, PHMSA said the cause of the blast must still be determined and the investigation is ongoing.

PHMSA administrator Marie Therese Dominguez met with agency investigators and Spectra representatives when she visited the blast site roughly 25 miles east of Pittsburgh earlier this week.

“This explosion was devastating – it injured one person, destroyed one home, and caused a fire that burned within a quarter-mile radius,” Dominguez said in a statement issued Wednesday. “We have directed the operator to take several immediate actions to determine the root cause of the failure, and to ensure the integrity of three nearby pipelines before they can be restarted.”

The agency gave Spectra 30 days to complete testing and analysis of the failed pipe as well as analysis of soil samples and any foreign materials.

The agency’s order detailed the conditions at the blast site where the explosion that threw a 24-1/2-foot section of 30-inch stainless steel pipe 100 feet and left a crater 12 feet deep, 30 feet wide and 50 feet long.

Spectra officials said as a precaution after the blast they drained natural gas from three adjacent pipelines.

PHMSA’s order calls for Spectra to uncover and inspect at least two sections of pipeline on either side of the pipeline that ruptured. If damage is discovered on those sections, “additional pipe must be exposed until at least 10 feet of undamaged pipe is exposed and examined.”

The blast damaged three homes, destroyed a fourth and left a 26-year-old man with extensive burns. It left a section of State Route 819 closed indefinitely while the Pennsylvania Department of Transportation assesses damage.