The Federal Energy Regulatory Commission allowed Texas Eastern to significantly increase the horsepower of its Delmont compressor station in November 2014, boosting the speed of gas flowing through the 35-year-old pipeline that exploded April 29 in Salem, Westmoreland County.
The faster gas flow from the compressor about 1½ miles upline could have caused corrosion inside the 30-inch diameter pipeline, according to two environmental organizations that have tracked recent expansion and operation of gas pipelines.
“I can’t say for certain there is a cause-effect relationship between the increases in [compressor] horsepower and the pipeline explosion, but it is information that should be part of the public discussion about this incident and pipeline safety in general,” said Ryan Talbot, an attorney with Appalachian Mountain Advocates, a nonprofit law and policy organization interested in shale gas and pipeline issues.
The U.S. Department of Transportation’s Pipeline and Hazardous Materials Safety Administration is investigating but has yet to determine the cause of the gas explosion that torched 40 acres in the semi-rural township 30 miles east of Pittsburgh, melted a roadway, damaged several homes and severely burned a man.
Darius Kirkwood, a PHMSA spokesman, issued a statement saying the agency is reviewing “all aspects” of Texas Eastern’s operations and the operator’s compliance with federal pipeline safety standards. If violations are found, the agency can issue an enforcement action, levy civil penalties or refer the case for criminal investigation.
Shortly after the explosion, PHMSA identified two areas of exterior pipeline corrosion related to flaws in the coating material applied to pipe welds.
The Delaware Riverkeeper Network raised concerns about the corrosive potential of the faster-flowing gas on the interior of the pipeline in an October 2013 comment letter about deficiencies in FERC’s review of Texas Eastern’s proposed 2014 compressor station and pipeline infrastructure expansion project.
According to the letter, FERC approved the compressor upgrades from 46,400 to 71,900 horsepower without requiring Texas Eastern to provide gas flow velocity data. Without that information, the letter said, it was impossible to know whether the compressor upgrades “pose long-term safety threats as a result of internal erosional velocity of entrained particles in the system.”
Aaron Stemplewicz, the Delaware Riverkeeper attorney who wrote the organization’s comment letter, said there are no federal regulations limiting gas flow velocity but there should be.
“It’s a gap that should be corrected,” Mr. Stemplewicz said. “FERC has recognized that gas flow velocity is a factor in determining if a pipeline will rupture. It needs to be regulated more closely.”
Creighton Welsh, a spokesman for Spectra Energy, which operates the Texas Eastern pipeline system, said metallurgic testing of the pipe from the explosion area is ongoing, and examining the interior of the pipe for corrosion is part of that investigation.
Mr. Welsh said that prior to the explosion, about 1.3 billion cubic feet of gas a day was moving through the the four pipelines in the right-of-way toward Northeast markets, “a typical amount for this time of year” and about half of the pipelines’ maximum capacity.
He said the company’s 2014 pipeline and compressor upgrade project increased that capacity by about 600 million cubic feet.
He said the company had completed its examination Monday of one of the four pipelines in the right-of-way where the explosion occurred — Line 19, a 30-inch diameter pipeline — and cleared it to return to operation.
Line 27, the one that exploded, Line 12, a 24-inch-diameter pipeline, and Line 28, a 36-inch-diameter pipeline, remain out of service.
Mr. Talbot said Line 12 poses special concerns. In 2009, Texas Eastern/ Spectra Energy asked and PHMSA approved a “special permit” that waives compliance with some safety regulations, including a line replacement requirement, for a 1.65-mile segment of the pipeline in an area where a number of new homes have been constructed near the pipeline right-of-way.
“I doubt that people living in the homes next to the Line 12 special permit segment know that they are living next to a pipeline that should either be replaced or be operating at reduced pressure,” Mr. Talbot said.
A meeting at which Salem Township supervisors, Spectra Energy representatives and emergency management officials will address the safety concerns of local residents is scheduled for 7 p.m. today at Congruity Presbyterian Church, 136 Fenneltown Road, New Alexandria.
Don Hopey: firstname.lastname@example.org, 412-263-1983, or on Twitter @donhopey.
First Published May 11, 2016 12:01 AM