NTSB will not investigate fatal Plum home explosion for now

The National Transportation Safety Board has opted not to investigate this month’s massive fatal explosion in Plum based on preliminary information that the source of the blast was inside the home that blew up — not in an outside pipeline.

That could change, as more details emerge about the disaster on Rustic Ridge Drive. But typically, the safety board, which investigates pipeline accidents, does not probe house explosions caused by internal sources.

Keith Holloway, a safety board spokesman, said his agency had an investigator at the scene in the days following the Aug. 12 catastrophe, which killed six people, including the owners of the home that exploded, Paul and Heather Oravitz.

Preliminary information “is that the source of the explosion is likely from inside the home,” Holloway told the Tribune-Review on Tuesday. “This is outside the jurisdiction which would prompt an NTSB investigation.”

Allegheny County has confirmed that the Fire Marshal’s Office is investigating reports that the Oravitzes were having problems with their hot water tank.

Officials have not disclosed further details.

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Four neighbors — Michael Thomas, Plum’s borough manager; Kevin Sebunia, known in the neighborhood as Mr. Fixit; Casey Clontz, a Peoples gas employee; and his 12-year-old son, Keegan Clontz — were also in the Oravitz residence at 141 Rustic Ridge Drive when it blew up about 10:20 a.m. All died.

The NTSB previously investigated a house explosion in Plum after a home on Mardi Gras Drive was leveled in March 2008, killing a man and injuring a 4-year-old girl.

In that case, the safety board determined that a contractor had nicked a natural gas pipeline outside the house five years earlier. The pipeline corroded over time and then suddenly failed, leading to the blast, according to the agency’s final report.

Gov. Josh Shapiro has ordered the state Department of Environmental Protection to probe whether any facilities that fall under the agency’s jurisdiction were involved in the explosion. Similarly, the independent state Public Utility Commission, which regulates utilities such as Peoples, the provider of natural gas to Plum, has launched its own investigation.

An official with the Allegheny County Fire Marshal’s Office said the probe into the cause of the blast could be prolonged, lasting months if not years.

DEP inspectors have flooded the area around the Rustic Ridge subdivision, using handheld detectors to find “stray” combustible gas, which could include methane, ethane, ethylene, propane, propylene, butanes, pentanes and hexane.

They have collected gas samples from the soil, surface pipelines and gas wells, using a hand pump and tubing to feed the invisible vapor into specialized bags. The bags are sent to a lab for analysis.

Inspectors have found traces of combustible gas in the Rustic Ridge area. They’re trying to find out whether stray vapors from pipelines or drilling operations in the area could have migrated into the Oravitz home and played a role in the explosion.

On Monday, DEP Secretary Richard Negrin visited Plum and revealed that a pinhole-sized leak had been discovered in a natural gas pipeline operated by Penneco, an oil and gas operator based in Delmont, about 350 feet southeast of the Oravitz home.

The leak occurred in a gathering pipeline linked to the Szitas Unit 1 well site, said Ben Wallace, Penneco’s chief operating officer.

Gathering lines move gas from the well sites into the transmission and distribution system.

Penneco and other companies operate several natural gas wells in Plum. All of them, as well as the DEP, checked the wells in the area as soon as the explosion occurred, Wallace said Tuesday.

“Everybody started checking their own facilities, and everybody shut off their own supplies of gas,” Wallace said. “We were out there while the first responders were still out there checking all of the facilities.”

The leak at the Szitas Unit 1 site was the only one found in the pipelines operated by Penneco and its affiliates, according to Wallace.

The gas company executive described the leak as routine and said he does not believe it played any role in the explosion.

“I would characterize this as a minor maintenance issue that needs corrected. It’s a typical maintenance issue that occurs in natural gas fields,” Wallace said. “We have zero reason to suspect this is in any way involved in the incident at Rustic Ridge.”

The company discovered the leak on the day of the explosion and notified the authorities. Evidence of the escaping gas could be heard, smelled and seen with the naked eye, Wallace said, adding it was too small of a puncture to show up on internal monitoring. He guessed the pipeline had been last inspected within a month of the blast.

Asked whether the NTSB took the discovery by Penneco of the pinhole leak into account when deciding not to launch an investigation, Holloway said he did not have any information about it.

Wallace, however, said Penneco notified authorities immediately upon finding the problem.

“The leak was identified to first responders at the moment it was found on the first day … so it was immediately identified,” Wallace said. “To the fire marshal, this isn’t new information.”

The DEP has directed oil and gas operators in the Rustic Ridge area to conduct gas migration investigations in addition to its own probe, Wallace said.

Samples are sent to specialized laboratories. Analysis likely will take months, Wallace said, since only a small number of labs perform that kind of work.

“The nature of taking the samples, of collecting them, of preparing them, the chain of custody, is just not that simple,” Wallace said.