Saturday’s catastrophic house explosion in Plum Borough, which killed five people, was the third and most violent in the northeast Allegheny County municipality in the last 15 years. But despite understandable concerns about systemic problems in the built or natural environment in that corner of the region, there are no obvious connections among them.
Still, the Pennsylvania Public Utilities Commission and Department of Environmental Protection should begin an exhaustive investigation not just into this weekend’s explosion, but into all possible ways the three blasts could be related, from geological features of the area to shared contractors and code enforcement. Residents of Plum Borough need to be reassured that their houses are safe.
Besides being located within Plum’s borders, it’s reassuring that there’s little on the surface that links the three explosions. In 2008 and 2022, the borough suffered two explosions within the same subsection of the Holiday Park neighborhood, the first on Mardi Gras Drive and the second on Hialeah Drive. Investigators later determined the 2008 blast, which killed one person and injured a second, was caused by a weakened natural gas line that had been damaged five years earlier by an excavator. In other words, it seems to have been a one-off accident.
The April 2022 incident, a smaller blast that resulted in no fatalities, is still under investigation.
Rustic Ridge Estates, site of Saturday’s explosion, is a full three miles from the Holiday Park subdivision, and was built much more recently: late 2000s vs. 1960s and 1970s. The blast there was also far more destructive, obliterating one house, destroying two due to the resulting fires, and damaging a dozen more.
Pennsylvania DEP maps of the region reveal a landscape pockmarked with oil and gas wells and scoured by mines, but Plum actually has less surface damage from mining than most Pittsburgh suburbs. A large natural gas transmission pipeline passes just north of Rustic Ridge, and a power transmission line passes through it, but this is also not an unusual convergence. Parts of the development are built on reclaimed mine land, but not where the explosion occurred — though it is possible for subterranean gases to migrate.
The most interesting feature in the Plum landscape, about one mile southeast of Rustic Ridge and two miles northwest of Holiday Park, is the Renton Mine. Ominously, the Renton Mine was the site of a 1920 disaster that buried nine miners. The mine is also the site of an ongoing underground fire, confirmed by the DEP in 2020 to be still burning after decades. Still, the geology is stable enough that Plum Borough just finished a new $20 million municipal complex adjacent to the Renton site.
No matter the ultimate cause of the disaster — which could take years to determine — the state should take seriously the concerns of Plum residents and exclude all possible connections among these disasters. The people of northeast Allegheny County deserve to feel safe in their own homes.
Correction: The original version of this editorial misstated the extent of undermining in Plum Borough. Plum is extensively undermined, but the Pennsylvania DEP reports only a few areas of surface damage from mining in the area.
First Published: August 14, 2023, 9:52 p.m.
Updated: August 15, 2023, 9:49 a.m.