The National Transportation Safety Board (NTSB) has released its final report on the March 24, 2023, natural gas explosion at the R.M. Palmer Company chocolate factory in West Reading, Pennsylvania. The explosion killed seven people, injured eleven, and caused significant damage to surrounding buildings. Investigators determined the blast was caused by gas that leaked from a retired 1982 Aldyl A plastic service tee with a Delrin insert, migrated through the ground, and ignited inside the facility. The tee’s failure was attributed to long-term degradation, exacerbated by exposure to elevated temperatures from a nearby leaking steam line.
The report underscored the vulnerability of plastic piping materials—particularly Aldyl A—to heat-related degradation. Elevated ground temperatures can accelerate slow crack growth and compromise material integrity, especially when older components are in service or not properly identified in system records. The NTSB found that the operator, UGI Corporation, lacked sufficient threat information in its Distribution Integrity Management Program (DIMP) to assess and mitigate risks posed by heat-exposed assets. The NTSB issued a Recommendation to PHMSA encouraging an Advisory Bulletin that advises operators to inventory plastic piping in elevated temperature environments and incorporate heat exposure as a threat factor in risk assessments.
Another key area of concern in the NTSB report was public awareness. Investigators noted that gas safety messages often fail to reach people who live or work in multifamily buildings or gathering places that do not receive direct billing communications. The report recommended expanded efforts to ensure the public understands how to recognize and respond to gas odors, as well as broader promotion of natural gas alarm installation. Improving outreach is critical, particularly in densely populated or high-occupancy areas that may be unaware of gas leak hazards.
The report also highlighted methane detection as a vital mitigation tool. The NTSB recommended wider adoption of natural gas alarms that meet National Fire Protection Association (NFPA) 715 standards in residential and commercial settings. The NTSB suggests that these alarms can provide early warning of a leak, allowing occupants to evacuate before gas accumulates to dangerous levels. The responsibility for requiring alarms will largely fall to state and local policymakers, and APGA is working to educate its members on detection technologies and promote codes and standards that support practical, effective use of methane detection in their communities.