(EMERGENCY SERVICES) Allegheny County Fire Marshal Provides Update on Plum House Explosion Investigation

PITTSBURGH – The Allegheny County Fire Marshal (ACFM) today provided an update on its investigation into the August 12, 2023 Plum house explosion. As lead investigator, ACFM will determine origin and cause upon the conclusion of its investigation.

To date, ACFM has completed scene safety and security, additional agency notifications, witness statements, interviews and processing of the incident site. The office’s on-scene investigative efforts have also been completed.
Several joint investigative efforts have been initiated and remain in process with agencies including the Pennsylvania Department of Environmental Protection, the Pennsylvania Public Utility Commission, Plum Police Department, Peoples Gas, and several represented insurance carriers. The most recent joint investigative meeting was held last week with the following findings:

The point of origin for the explosion is within the home at 141 Rustic Ridge. Several levels of testing and sampling were completed from the start of this investigation. The results of all known testing to date were reviewed and discussed within the joint investigative meeting. All potential outside factors like wells, pipelines, ground gas propagation and other utilities were all inspected and tested at several levels by each of the associated agencies and companies. All findings to date confirm that there are no factors external to the home that exploded that led to the explosion.

Testing and sampling that was completed by the agencies involved included, but was not limited to soil gas monitor, mobile leak survey, electric resistivity imaging (looks for variations in the ground), multi-channel analysis (looks for changes in the ground subsurface), ground penetrating radar (looks for underground utilities), and frequency domain electromagnetic scan (looks for abandoned wells).

The originating property at 141 Rustic Ridge will be turned back over to the property owners and representatives. ACFM continues to work with local officials regarding further scene remediation efforts to make the incident scene safe.

Follow up interviews are being completed with some of the responders and witnesses, as is normal for an investigation of this type. The cause of the incident continues to be investigated with further analysis of the interviews and the physical evidence retrieved.

Under state law, ACFM is tasked with investigating the origin and cause of fires and explosions that occur in Allegheny County. The process to confirm the origin and cause may include interviews, investigative photography/videography, drone imagery and 3D scans, debris layering, scene reconstruction, examination of all utility connections and circuitry, application of the scientific method, and other measures as appropriate. The process is often long and involved as investigators review every possibility to ensure that they have as much information as they can before issuing any determination.

As additional information becomes available, it will be released via press release after appropriate notifications are made. There is no time frame for when the investigation will be complete.

Finally, ACFM is using this opportunity to encourage homeowners to install combustible gas detectors, and also reminds residents of these best practices:

If you smell natural gas, do NOT turn on any appliances or light switches.
Exit the house and go to a safe area away from the house.
Call 9-1-1 from outside of the house.
Call the gas company from outside of the house.
Do not re-enter the house.
Wait for first responders to arrive.