{"operation":"document","citation":"PLD23LR002","title":"UGI Corporation Natural Gas–Fueled Explosion and Fire","source_type":"incident","agency":"National Transportation Safety Board","status":"current","official":true,"published_on":"2025-04-18","effective_on":"2023-03-24","summary":"Accident. in West Reading, PA, USA. on 2023-03-24. UGI Utilities. Leak/explosion/fire","machine_formats":{"json":"https://regulus.evalyn.ai/document/ntsb-case-pld23lr002.json","markdown":"https://regulus.evalyn.ai/document/ntsb-case-pld23lr002.md"},"app_url":"https://regulus.evalyn.ai/document/ntsb-case-pld23lr002","source_url":"https://www.ntsb.gov/investigations/Pages/PLD23LR002.aspx","body":"NTSB investigation PLD23LR002.\n\nEvent Type: Accident\n\nEvent Date: 2023-03-24\n\nEvent City: West Reading\n\nEvent State Or Region: PA\n\nEvent Country: USA\n\nPipeline Operator: UGI Utilities\n\nPipeline Type: Distribution\n\nAccident Type: Leak/explosion/fire\n\nCompletion Status: Completed\n\nReport Number: PIR2501\n\nReport Date: 2025-03-18\n\nProbable cause: The National Transportation Safety Board determines that the probable cause of the explosion was degradation of a retired 1982 Aldyl A polyethylene service tee with a Delrin polyacetal insert that allowed natural gas to leak and migrate underground into the R.M. Palmer Company candy factory buildings, where it was ignited by an unknown source. Contributing to the degradation of the service tee and insert were significantly elevated ground temperatures from steam escaping R.M. Palmer Company’s corroded underground steam pipe, located near the service tee, that had been unmarked and cracked. Contributing to the steam pipe crack was soil movement and R.M. Palmer Company’s lack of awareness of the pipe’s corroded state. Contributing to the natural gas leak was UGI Corporation’s lack of awareness of the nearby steam pipe, which led to an incomplete integrity management program evaluation that did not consider or manage the risk posed by the steam pipe. Contributing to the accident’s severity was R.M. Palmer Company’s insufficient emergency response procedures and training of its employees, who did not understand the hazard and did not evacuate the buildings before the explosion.\n\nTier1Name: System operating, changing flow/pressure\n\nTier2Name: System disabled\n\nTier1Name: Initiating product flow\n\nTier2Name: Pressure/flow/temp event\n\nTier1Name: Post-release\n\nTier2Name: Emergency shutoff\n\nTier1Name: Emergency response\n\nTier2Name: Fire/explosion (post-release)\n\nTier1Name: System not operating\n\nTier2Name: Servicing event\n\nTier1Name: System operating\n\nTier2Name: Servicing event\n\nFinding Tier1Name: Organizational\n\nFinding Tier2Name: Support/oversight/monitoring\n\nFinding Tier3Name: Safety programs\n\nFinding Modifier Name: Pipeline operator\n\nFinding Report Text: Organizational - Support/oversight/monitoring - Safety programs - Pipeline operator\n\nFinding Tier1Name: Organizational\n\nFinding Tier2Name: Support/oversight/monitoring\n\nFinding Tier3Name: Training\n\nFinding Modifier Name: Pipeline operator\n\nFinding Report Text: Organizational - Support/oversight/monitoring - Training - Pipeline operator\n\nFinding Tier1Name: Organizational\n\nFinding Tier2Name: Support/oversight/monitoring\n\nFinding Tier3Name: Safety programs\n\nFinding Modifier Name: State/Local agency\n\nFinding Report Text: Organizational - Support/oversight/monitoring - Safety programs - State/Local agency\n\nFinding Tier1Name: Organizational\n\nFinding Tier2Name: Management\n\nFinding Tier3Name: Communication (organizational)\n\nFinding Modifier Name: Other institution/organization\n\nFinding Report Text: Organizational - Management - Communication (organizational) - Other institution/organization\n\nFinding Tier1Name: Organizational\n\nFinding Tier2Name: Management\n\nFinding Tier3Name: Policy/procedure\n\nFinding Modifier Name: Other institution/organization\n\nFinding Report Text: Organizational - Management - Policy/procedure - Other institution/organization\n\nFinding Tier1Name: Organizational\n\nFinding Tier2Name: Support/oversight/monitoring\n\nFinding Tier3Name: Safety programs\n\nFinding Modifier Name: Federal agency\n\nFinding Report Text: Organizational - Support/oversight/monitoring - Safety programs - Federal agency\n\nFinding Tier1Name: Environment/Infrastructure\n\nFinding Tier2Name: Operating environment/control system\n\nFinding Tier3Name: Sensor/detector coverage/availability\n\nFinding Modifier Name: Contributed to outcome\n\nFinding Report Text: Environment/Infrastructure - Operating environment/control system - Sensor/detector coverage/availability - Contributed to outcome\n\nFinding Tier1Name: Pipeline\n\nFinding Tier2Name: Pipline systems/equipment\n\nFinding Tier3Name: Fittings\n\nFinding Modifier Name: Damaged/degraded\n\nFinding Report Text: Pipeline - Pipline systems/equipment - Fittings - Damaged/degraded\n\nFinding Tier1Name: Environment/Infrastructure\n\nFinding Tier2Name: Conditions/weather/phenomena\n\nFinding Tier3Name: Temperature\n\nFinding Modifier Name: Effect on equipment\n\nFinding Report Text: Environment/Infrastructure - Conditions/weather/phenomena - Temperature - Effect on equipment\n\nFinding Tier1Name: Pipeline\n\nFinding Tier2Name: Miscellaneous equipment\n\nFinding Tier3Name: Misc equipment/hardware\n\nFinding Modifier Name: Damaged/degraded\n\nFinding Report Text: Pipeline - Miscellaneous equipment - Misc equipment/hardware - Damaged/degraded\n\nFinding Tier1Name: Environment/Infrastructure\n\nFinding Tier2Name: Physical environment\n\nFinding Tier3Name: Soil\n\nFinding Modifier Name: Effect on equipment\n\nFinding Report Text: Environment/Infrastructure - Physical environment - Soil - Effect on equipment\n\nFinding Tier1Name: Pipeline\n\nFinding Tier2Name: Pipline systems/equipment\n\nFinding Tier3Name: Fittings\n\nFinding Modifier Name: Damaged/degraded\n\nFinding Report Text: Pipeline - Pipline systems/equipment - Fittings - Damaged/degraded\n\nFinding Tier1Name: Environment/Infrastructure\n\nFinding Tier2Name: Operating environment/control system\n\nFinding Tier3Name: Markings/signage\n\nFinding Modifier Name: Awareness of condition\n\nFinding Report Text: Environment/Infrastructure - Operating environment/control system - Markings/signage - Awareness of condition\n\nOfficial NTSB investigation data. NTSB findings determine probable cause and make safety recommendations; they do not adjudicate civil liability or regulatory violations.\n\nWhat Happened\nOn March 24, 2023, around 4:55 p.m., natural gas, which was transported through a UGI Corporation–owned pipeline, leaked into and accumulated in the basement of an R.M. Palmer Company candy factory building in West Reading, Pennsylvania. The gas ignited, causing an explosion and fire that killed 7 Palmer employees, injured 10 people, and destroyed the building. Another Palmer building, as well as an adjacent apartment building, were also severely damaged. Three families were displaced from the apartment building.\n\nSafety issues included degradation of a retired service tee, insufficient consideration of threats to pipeline integrity, the risk associated with unmarked private pipeline assets crossing public rights-of-way (for example, a public street), delayed evacuation of Building 2 despite detection of natural gas, natural gas safety messaging that may not reach certain members of the public, insufficient guidance on gas leak emergency procedures, absence of natural gas detection alarms in commercial buildings, and insufficient accessibility of gas distribution line valves.\n\nWhat We Found\nWe determined that the probable cause of the explosion was degradation of a retired 1982 Aldyl A polyethylene service tee with a Delrin polyacetal insert that allowed natural gas to leak and migrate underground into the R.M. Palmer Company candy factory buildings, where it was ignited by an unknown source.\nContributing to the degradation of the service tee and insert were significantly elevated ground temperatures from steam escaping R.M. Palmer Company’s corroded underground steam pipe, located near the service tee, that had been unmarked and cracked. Contributing to the steam pipe crack was soil movement and R.M. Palmer Company’s lack of awareness of the pipe’s corroded state. Contributing to the natural gas leak was UGI Corporation’s lack of awareness of the nearby steam pipe, which led to an incomplete integrity management program evaluation that did not consider or manage the risk posed by the steam pipe.\nContributing to the accident’s severity was R.M. Palmer Company’s insufficient emergency response procedures and training of its employees, who did not understand the hazard and did not evacuate the buildings before the explosion.\n\nWhat We Recommended\nAs a result of this investigation, we issued 18 new recommendations. Read the complete list of recommendations. We issued recommendations to:\nthe Pipeline and Hazardous Materials Safety Administration,\nthe Occupational Safety and Health Administration,\n50 states along with the Commonwealth of Puerto Rico and the District of Columbia,\nthe Commonwealth of Pennsylvania,\nthe Pennsylvania Public Utility Commission,\nthe American Gas Association,\nthe American Petroleum Institute,\nthe Gas Piping Technology Committee,\nthe Common Ground Alliance,\nthe International Code Council,\nthe National Fire Protection Association,\nUGI Corporation, and\nR.M. Palmer Company.\n\nWe also reiterated the following safety recommendation:\n\nTo the Pipeline and Hazardous Materials Safety Administration:\nEvaluate industry’s implementation of the gas distribution pipeline integrity management requirements and develop updated guidance for improving their effectiveness. The evaluation should specifically consider factors that may increase the likelihood of failure such as age, increase the overall risk (including factors that simultaneously increase the likelihood and consequence of failure), and limit the effectiveness of leak management programs. (P-21-2)\n\nPIR-25-01\n<<<PAGE 1>>>\n\nMarch 18, 2025 Pipeline Investigation Report PIR-25-01\nUGI Corporation Natural Gas-Fueled\nExplosion and Fire\nWest Reading, Pennsylvania\nMarch 24, 2023\nAbstract: This report discusses the March 24, 2023, natural gas–fueled explosion and\nfire at Building 2 of the R.M. Palmer Company, a candy manufacturer located in West\nReading, Pennsylvania. The explosion destroyed the manufacturer’s Building 2 and\ncaused significant structural damage to its adjacent Building 1 and other surrounding\nstructures. In total, 7 people were killed, 10 people were injured, and 3 families were\ndisplaced from a neighboring apartment building.\nSafety issues identified in this report include degradation of a retired service tee,\ninsufficient consideration of threats to pipeline integrity, the risk associated with\nunmarked private pipeline assets crossing public rights-of-way (for example, a public\nstreet), delayed evacuation of Building 2 despite detection of natural gas, natural gas\nsafety messaging that may not reach certain members of the public, insufficient\nguidance on gas leak emergency procedures, absence of natural gas detection\nalarms in commercial buildings, and insufficient accessibility of gas distribution line\nvalves.\nAs part of this investigation, the National Transportation Safety Board issued\nrecommendations to the Pipeline and Hazardous Materials Safety Administration, the\nOccupational Safety and Health Administration, 50 states along with the\nCommonwealth of Puerto Rico and the District of Columbia, the Commonwealth of\nPennsylvania, the Pennsylvania Public Utility Commission, the American Gas\nAssociation, the American Petroleum Institute, the Gas Piping Technology\nCommittee, the Common Ground Alliance, the International Code Council, the\nNational Fire Protection Association, UGI Corporation, and R.M. Palmer Company.\n\n<<<PAGE 2>>>\n\nPipeline Investigation Report\nReport Number PIR-25-01\nContents\nFigures ..................................................................................................................iv\nTables .................................................................................................................. v\nAcronyms and Abbreviations ................................................................................vi\nExecutive Summary ..............................................................................................vii\nWhat Happened.............................................................................................................. vii\nWhat We Found .............................................................................................................. vii\nWhat We Recommended ............................................................................................... ix\n1 Factual Information .................................................................................. 1\n1.1 The Accident ........................................................................................................... 1\n1.1.1 Area Layout ...................................................................................................... 2\n1.1.2 Service Line and Tee Replacement at Palmer Building 2 ........................... 5\n1.1.3 Natural Gas Leak and Explosion .................................................................... 8\n1.2 Injuries and Damages from the Explosion and Gas Fire ................................. 12\n1.3 Emergency Response........................................................................................... 12\n1.3.1 R.M. Palmer Emergency Response ............................................................. 13\n1.3.2 Local Emergency Response ......................................................................... 13\n1.3.3 UGI Emergency Response ............................................................................ 14\n1.4 R.M. Palmer Facilities and Heating System........................................................ 16\n1.5 UGI Corporation ................................................................................................... 17\n1.5.1 Cherry Street Gas Main and Service Information ...................................... 17\n1.5.2 UGI Leak Surveys Since 2011 ....................................................................... 19\n1.5.3 Valve Inspections ........................................................................................... 19\n1.6 Postaccident Examinations and Testing ............................................................ 21\n1.6.1 On-Scene Examinations ................................................................................ 22\n1.6.2 Laboratory Examinations and Research ..................................................... 30\n1.7 Regulations, Advisories, and Standards ............................................................ 38\n1.7.1 Pipeline and Hazardous Materials Safety Administration ........................ 38\n1.7.2 Pennsylvania Public Utility Commission ..................................................... 39\n1.7.3 Occupational Safety and Health Administration ....................................... 40\ni\n\n<<<PAGE 3>>>\n\nPipeline Investigation Report\nReport Number PIR-25-01\n1.7.4 Codes .............................................................................................................. 40\n1.8 Plans, Procedures, and Programs ....................................................................... 42\n1.8.1 R.M. Palmer .................................................................................................... 42\n1.8.2 UGI Corporation ............................................................................................ 44\n1.9 Postaccident Actions ............................................................................................ 49\n1.9.1 Occupational Safety and Health Administration Investigation ................ 49\n1.9.2 Pennsylvania Public Utility Commission ..................................................... 50\n1.9.3 R.M. Palmer .................................................................................................... 51\n1.9.4 UGI Corporation ............................................................................................ 51\n1.10 Pennsylvania Public Utility Commission Party Removal ................................... 54\n2 Analysis................................................................................................... 55\n2.1 Introduction ........................................................................................................... 55\n2.2 The Accident ......................................................................................................... 56\n2.2.1 Source of Natural Gas that Fueled the Explosion...................................... 56\n2.2.2 Delayed Evacuation ....................................................................................... 62\n2.3 Insufficient Consideration of Known Threats from Plastic Piping ................... 64\n2.4 Unmarked Private Assets in Public Rights-of-Way ............................................ 69\n2.5 Public Awareness and Preparedness ................................................................. 71\n2.5.1 Natural Gas Alarms ........................................................................................ 73\n2.5.2 Companies’ Emergency Response Procedures ........................................ 77\n2.6 Valve Accessibility ................................................................................................. 78\n2.7 Withholding Safety-Related Information from the NTSB ................................. 80\n3 Conclusions ............................................................................................ 82\n3.1 Findings ................................................................................................................. 82\n3.2 Probable Cause ..................................................................................................... 84\n4 Recommendations .................................................................................. 85\n4.1 New Recommendations ....................................................................................... 85\n4.2 Previously Issued Recommendation Reiterated in This Report ...................... 87\nAppendixes ......................................................................................................... 89\nAppendix A: Investigation ............................................................................................ 89\nAppendix B: Consolidated Recommendation Information ..................................... 90\nii\n\n<<<PAGE 4>>>\n\nPipeline Investigation Report\nReport Number PIR-25-01\nReferences........................................................................................................... 96\niii\n\n<<<PAGE 5>>>\n\nPipeline Investigation Report\nReport Number PIR-25-01\nFigures\nFigure 1. Overhead image of the accident. ........................................................................ 2\nFigure 2. South 2nd Avenue before the accident. ............................................................. 3\nFigure 3. Arrangement of Palmer-owned pipes. ................................................................ 4\nFigure 4. Natural gas distribution system and Palmer-owned pipes. .............................. 6\nFigure 5. Cherry Street gas main and Building 2 service tees, viewed from above. ..... 8\nFigure 6. Underground gas main valves involved in response to the March 24\nincident. ................................................................................................................................. 15\nFigure 7. Aldyl A service tee and its components. ........................................................... 18\nFigure 8. South 2nd Avenue and Penn Avenue intersection in 2018 and during an\nexcavation in 2024; water valve A had a gas cover. ......................................................... 21\nFigure 9. Bar hole test readings conducted in March 2023 and April 2023. ................ 24\nFigure 10. Smoke from conduit visible near gas service line to Building 2. ................. 27\nFigure 11. Excavation of pipes at the accident location. ................................................. 27\nFigure 12. A view of one of the chocolate pipe conduits from the Building 2\nbasement. .............................................................................................................................. 29\nFigure 13. Longitudinal fracture in retired service tee. ................................................... 31\nFigure 14. Interior of retired service tee tower with top portion of Delrin insert\nmissing. .................................................................................................................................. 32\nFigure 15. Longitudinal fracture from top to base of tower and detailed image of slow\ncrack growth region. ............................................................................................................ 33\nFigure 16. Image of fracture surface on Delrin insert for retired service tee. ............... 34\nFigure 17. Through-wall cracks in steam pipe. ................................................................. 36\nFigure 18. UGI crew during service line replacement project, 2021. ............................ 37\niv\n\n<<<PAGE 6>>>\n\nPipeline Investigation Report\nReport Number PIR-25-01\nTables\nTable 1. Surveillance camera data from in and around Buildings 1 and 2 before the\nexplosion. .............................................................................................................................. 11\nTable 2. Reported valve inspections. ................................................................................. 20\nTable 3. Estimated UGI Aldyl A and total assets. .............................................................. 47\nTable 4. Palmer OSHA-issued violations. .......................................................................... 50\nv\n\n<<<PAGE 7>>>\n\nPipeline Investigation Report\nReport Number PIR-25-01\nAcronyms and Abbreviations\nAPI American Petroleum Institute\nCEO Palmer Chief Executive Officer\nCFR Code of Federal Regulations\nCGA Common Ground Alliance\nDDRM data-driven risk model\nGOM Gas Operations Manual\nDIMP distribution integrity management program\nGIS geographic information system\nGPTC Gas Piping Technology Committee\nGPTC Guide Guide for Gas Transmission, Distribution, and Gathering Piping\nSystems\nICC International Code Council\nIFC International Fuel Code\nIFGC International Fuel Gas Code\nIM integrity management\nInside SLIP inside service line inspection program\nNFPA National Fire Protection Association\nNFPA 54 National Fuel Gas Code\nNPRM notice of proposed rulemaking\nOSHA Occupational Safety and Health Administration\nPA One Call Pennsylvania One Call System\nPA PUC Pennsylvania Public Utility Commission\nPHMSA Pipeline and Hazardous Materials Safety Administration\npsig pounds per square inch, gauge\nPSMS pipeline safety management system\nRP Recommended Practice\nSME subject-matter expert\nVP Palmer vice president of operations and technical services\nvi\n\n<<<PAGE 8>>>\n\nPipeline Investigation Report\nReport Number PIR-25-01\nExecutive Summary\nWhat Happened\nOn March 24, 2023, around 4:55 p.m., natural gas, which was transported\nthrough a UGI Corporation–owned pipeline, leaked into and accumulated in the\nbasement of an R.M. Palmer Company candy factory building in West Reading,\nPennsylvania. The gas ignited, causing an explosion and fire that killed 7 Palmer\nemployees, injured 10 people, and destroyed the building. Another Palmer building,\nas well as an adjacent apartment building, were also severely damaged. Three\nfamilies were displaced from the apartment building.\nWhat We Found\nIn 2021, a UGI Corporation crew retired the Aldyl A polyethylene service tee,\njoining UGI’s gas main to the service line for Palmer Building 2. The crew capped off\nthe retired tee, which had been installed in 1982, and installed a new tee. The retired\nAldyl A tee remained connected to the natural gas distribution system. We found that\nnatural gas had migrated from the retired Aldyl A service tee through the ground\nthen into the Palmer Building 2 basement, chocolate pipe conduits, and Building 1,\nand fueled the explosion in the Building 2 basement. We found that the 1982 retired\nservice tee leaked because of degradation (slow crack growth of the Aldyl A tower\nshell and thermal decomposition of the Delrin insert) caused by exposure to elevated\ntemperatures. Steam escaping through a crack in a corroded steam pipe nearby had\nsignificantly elevated the ground temperatures near the tee. We found that the\nomission from PA's One Call law of certain assets whose lines transport steam or\nother high temperature substances across public rights-of-way can pose a risk during\nnearby excavation. We further found that widespread adoption of best practices on\n811 center membership can increase awareness of certain underground pipelines\nthat cross public rights-of-way and prevent an accident like this one.\nWe found that, without sufficient threat information available for analysis in its\ndistribution integrity management program (DIMP), UGI could not effectively evaluate\nand address the risk to pipeline integrity of plastic piping in elevated temperature\nenvironments and that by not addressing the threat posed by the steam pipe, UGI’s\nDIMP was not effective in preventing the accident. We further found that operators\nmay not be aware of where they may have plastic natural gas assets that are\nvulnerable to degradation in elevated temperature environments, so appropriate\nmitigations may not be in place. In this accident, we found that UGI lacked\nprocedures and training for its field crews to report sources of elevated temperatures\nvii\n\n<<<PAGE 9>>>\n\nPipeline Investigation Report\nReport Number PIR-25-01\nnear their assets thus the threat posed by the steam pipe was not identified, and\nmitigative measures were not implemented. In addition, industry guidance\nhighlighting the threat to pipeline integrity of exposure to elevated temperatures\ncould improve awareness so that operators can effectively identify and manage the\nthreat.\nAlthough several employees reported smelling the gas in the buildings before\nthe explosion, few evacuated. We found that had Palmer implemented natural gas\nemergency procedures and training before the accident, employees and managers\ncould have responded by immediately evacuating and moving to a safe location. We\nfurther found that when businesses that use natural gas do not have natural gas\nemergency procedures and training, employees may be unaware or unsure of what\nto do if they smell natural gas. Further, we determined that natural gas alarms can\nalert people of a gas leak so they can evacuate the area; however, natural gas\ncustomers may not be aware of the necessity of such alarms. We also found that,\nbecause of their consensus-based nature and wide reach, model building or gas\ncodes can be effective instruments to address natural gas–related risks to employees\nof businesses that use natural gas. Because adoption of these fuel gas codes and\nother rules related to natural gas alarms depends on state and local policies,\nwidespread requirement of natural gas alarms will rely on action at the state and local\nlevel.\nWe found that natural gas pipeline operator public awareness programs may\nnot reach certain members of the public who do not directly receive bill stuffers,\nmaking them potentially unaware of natural gas safety guidance. Further, because\ncustomers vary significantly in the number of occupants or residents, criteria for\ndesignating emergency valves that only count customers may not accurately reflect\nwho could be affected by a natural gas outage or emergency or the severity of the\neffect. We also found that UGI did not effectively inspect and maintain its valves\nthrough its valve maintenance program, which led to a delay in shutting off gas to the\naffected area. Lastly, we found that the Pennsylvania Public Utility Commission\nrefused to provide investigative information pursuant to the NTSB’s federal authority.\nWe determined that the probable cause of the explosion was degradation of a\nretired 1982 Aldyl A polyethylene service tee with a Delrin polyacetal insert that\nallowed natural gas to leak and migrate underground into the R.M. Palmer Company\ncandy factory buildings, where it was ignited by an unknown source. Contributing to\nthe degradation of the service tee and insert were significantly elevated ground\ntemperatures from steam escaping R.M. Palmer Company’s corroded underground\nsteam pipe, located near the service tee, that had been unmarked and cracked.\nContributing to the steam pipe crack was soil movement and R.M. Palmer Company’s\nviii\n\n<<<PAGE 10>>>\n\nPipeline Investigation Report\nReport Number PIR-25-01\nlack of awareness of the pipe’s corroded state. Contributing to the natural gas leak\nwas UGI Corporation’s lack of awareness of the nearby steam pipe, which led to an\nincomplete integrity management program evaluation that did not consider or\nmanage the risk posed by the steam pipe. Contributing to the accident’s severity was\nR.M. Palmer Company’s insufficient emergency response procedures and training of\nits employees, who did not understand the hazard and did not evacuate the buildings\nbefore the explosion.\nWhat We Recommended\nWe recommended that the Pipeline and Hazardous Materials Safety\nAdministration (PHMSA) issue an advisory bulletin reviewing the details of this\naccident to natural gas distribution pipeline operators and advising them to address\nthe risk associated with Aldyl A service tees with Delrin inserts by replacing or\nremediating them. We also recommended that PHMSA issue an advisory bulletin to\noperators referencing DIMP regulations and encouraging a one-time inventory of all\nplastic assets that are located in environments that experience or are at risk of\nelevated temperatures, identifying plastic assets in elevated temperature\nenvironments, and evaluating and mitigating risks to deter the degradation of these\nassets. In addition, we recommended that UGI inventory all its plastic natural gas\nassets that may be in elevated temperature environments and address the risk\nassociated with these assets. We reiterated a 2021 recommendation to PHMSA to\nevaluate industry implementation of gas distribution pipeline integrity management\nrequirements and develop updated guidance for improving the effectiveness of the\nrequirements.\nWe further recommended that PHMSA find effective ways for operators to\ncommunicate with people who live, work, or congregate near natural gas distribution\npipelines and help operators improve public awareness of natural gas safety. We\nthen recommended that, based on these findings, the American Petroleum Institute\nupdate its public awareness standard to provide specific guidance to natural gas\ndistribution pipeline operators on effective safety communications.\nWe recommended that the Occupational Safety and Health Administration\nrequire employers whose facilities use natural gas to implement natural gas\nemergency procedures and that Palmer revise its natural gas emergency procedure\nto direct all employees to immediately evacuate to a safe location when they smell\nnatural gas. We also recommended that Pennsylvania modify its law on underground\nutility protection to require all owners and operators of pipelines transporting steam\nor other high-temperature materials located in public rights-of-way to register their\nix\n\n<<<PAGE 11>>>\n\nPipeline Investigation Report\nReport Number PIR-25-01\nassets with Pennsylvania One Call and that the Common Ground Alliance identify\nopportunities for improving adoption of its best practices on 811 center membership.\nTo make sure operators consider consequences and emergency response times in\ndetermining the locations of critical valves, we recommended the Pennsylvania Public\nUtility Commission assess operators’ methodology for this determination.\nWe recommended that the American Gas Association share the details of this\naccident with its members, encouraging them to evaluate the effectiveness of their\npublic awareness programs and to promote the installation of natural gas alarms. We\nalso recommended that the Gas Piping Technology Committee develop guidance to\nensure natural gas pipeline operators’ DIMPs appropriately assess and address\nthreats to plastic pipelines from nearby temperature-elevating assets.\nWe recommended that 50 states, Puerto Rico, and the District of Columbia\nrequire the installation of natural gas alarms and that the International Code Council\nand the National Fire Protection Association revise codes to provide for natural gas\nemergency procedures and revise the fuel gas codes to provide for the required\ninstallation of natural gas alarms.\nFinally, we recommended that the Commonwealth of Pennsylvania review and\namend its statutes to facilitate sharing investigative information with the NTSB.\nx\n\n<<<PAGE 12>>>\n\nPipeline Investigation Report\nReport Number PIR-25-01\n1 Factual Information\n1.1 The Accident\nOn March 24, 2023, about 4:55 p.m. local time, a natural gas–fueled explosion\nand fire occurred at Building 2 of the R.M. Palmer Company candy factory in West\nReading, a borough in Berks County, Pennsylvania. The explosion destroyed Building\n2 and caused significant structural damage to the adjacent Building 1 and other\nsurrounding structures, including an apartment building. (See figure 1.) In total,\n7 people were killed, 10 people were injured, and 3 families were displaced from\ntheir apartments. The accident caused an estimated $42 million in property\ndamage.\n1 Weather conditions at the time of the accident were clear with no\nprecipitation, the temperature was 52°F, and winds were about 5 mph from the\nsouthwest by south.\n1 Visit ntsb.gov to find additional information in the public docket for this NTSB accident\ninvestigation (case number PLD23LR002). Use the CAROL Query to search safety recommendations\nand investigations.\n1\n\n<<<PAGE 13>>>\n\nPipeline Investigation Report\nReport Number PIR-25-01\nFigure 1. Overhead image of the accident. (Source: Western Berks Fire Department.)\n1.1.1 Area Layout\nBuilding 2, a two-story brick structure, was located at 17 South 2nd Avenue in\nWest Reading. The four-story brick Building 1 was located at 77 South 2nd Avenue,\nsouth of Building 2. Cherry Street, a public right-of-way (alley), separated the two\nbuildings. The affected apartment building, which comprised three households, was\nlocated 5 feet north of Building 2. (See figure 2.)\n2\n\n<<<PAGE 14>>>\n\nPipeline Investigation Report\nReport Number PIR-25-01\nFigure 2. South 2nd Avenue before the accident. (Source: Google Photos.)\nUGI Corporation owned and operated natural gas pipeline assets located\nwithin the public right-of-way near the accident site.2 Natural gas was distributed to\nPalmer Buildings 1 and 2 from a UGI natural gas main that ran lengthwise underneath\nCherry Street (Cherry Street main).\n3 Near the intersection with South 2nd Avenue, the\nCherry Street main transitioned from a short section of steel and then reduced to a\n1.25-inch-diameter Aldyl A main, which was installed in 1982 (see section 1.5.1).\n4\nAldyl A is the trademarked name of a polyethylene plastic gas pipeline product that\nwas manufactured by the DuPont chemical company using a proprietary polymer\nresin. At the time of the accident, the Cherry Street main was operating about 53\npounds per square inch, gauge (psig). The maximum allowable operating pressure of\nthe Cherry Street main was 60 psig. The main was about 3 feet below the road\nsurface.\nPalmer produces chocolate novelty candies for sale in the United States and\ninternationally and has been in business in Pennsylvania since 1948. It has about 550\nfull-time employees and about 300 seasonal workers. Palmer’s facilities at the time of\nthe accident comprised six buildings, two in West Reading and four in Wyomissing,\n2 (a) See section 1.5 for UGI company information. (b) This report uses the term asset to refer to\nthe specific elements of a pipeline distribution system.\n3 A gas main is a natural gas distribution pipeline that serves as a common source of supply for\nmore than one service line. Service lines transport gas to a customer.\n4 In 1982, the Aldyl A gas main was installed by inserting it into a bare steel main from 1911. As\nwas common practice at the time, once the Aldyl A main was inserted, the steel main was then\nabandoned. An abandoned pipeline is one permanently removed from service, no longer containing\nnatural gas, as defined in Title 49 Code of Federal Regulations (CFR) 192.3.\n3\n\n<<<PAGE 15>>>\n\nPipeline Investigation Report\nReport Number PIR-25-01\nPennsylvania. In West Reading, Building 1 was used for candy production and as\ncorporate headquarters, and Building 2 was used for candy production. Palmer-\nowned pipes (private pipes) ran underneath Cherry Street between Buildings 1 and\n2: a steam pipe that delivered steam from the boiler to heat areas of Building 2, a\ncondensate pipe that channeled condensation back to the boiler, and two conduits\nthat together contained six supply pipes that delivered liquid chocolate from storage\ntanks in the basement of Building 2 to production areas in Building 1.\n5 One conduit\ncontained four chocolate supply pipes, and the other conduit contained two\nchocolate pipes. (See figure 3.) Electric heat tape affixed to the outside of the\nchocolate pipes kept the chocolate from solidifying in the pipes. The top of the steam\npipe was about 1.5 feet below the road surface.6\nFigure 3. Arrangement of Palmer-owned pipes.\n5 These pipes were partially destroyed in the explosion and are no longer in use.\n6 Palmer began production in Building 2 in the mid-1960s. The National Transportation Safety\nBoard (NTSB) interviewed a former Palmer employee who indicated the steam pipe had been installed\nbefore he began working there in the mid-1970s.\n4\n\n<<<PAGE 16>>>\n\nPipeline Investigation Report\nReport Number PIR-25-01\nThe Palmer-owned pipes laid above and perpendicular to the gas main, with\nsteam flowing from Building 1 to Building 2. Palmer kept maintenance records of the\nsteam heating system boiler unit. These records indicated that the unit was checked\ndaily by Palmer mechanics and inspected annually by a contractor, but Palmer did not\nhave any maintenance records for the steam pipe to Building 2.\n1.1.2 Service Line and Tee Replacement at Palmer Building 2\nTwo years before this accident, on February 16, 2021, a UGI crew conducted a\nroutine inspection of the Building 2 gas meter, which at the time was in the\nbasement.7 The crew detected gas inside the basement of Building 2 and at the\nservice curb valve outside the building. UGI recorded this as a “grade C” leak, which\nrequired immediate attention or repair, and began a project to replace the service\nline and service tee from the Cherry Street gas main to Building 2 and to move the\nmeter outdoors as required by UGI procedures. The service tee joined the service\nline to the main. The alignment of the private pipes and natural gas distribution\nsystem assets after the replacement project is shown in figure 4.\n7 This type of inspection, required by UGI’s Gas Operations Manual (GOM) and federal\nregulation to be conducted every 3 years on a medium-pressure system, is described further in section\n1.5.2.\n5\n\n<<<PAGE 17>>>\n\nPipeline Investigation Report\nReport Number PIR-25-01\nFigure 4. Natural gas distribution system and Palmer-owned pipes.\nBefore beginning excavation to replace the service line and move the gas\nmeter, UGI submitted an emergency underground utility line locate request to the\nPennsylvania One Call System (PA One Call) to mark existing utilities so UGI could\nrepair a gas leak at Building 2.\n8 Pennsylvania’s Underground Utility Line Protection\nLaw, Pennsylvania Act 287, as amended, requires owners or operators of\nunderground lines that serve one or more customers or consumers in Pennsylvania to\nbe a member of PA One Call, a privately funded nonprofit corporation that facilitates\nutility line location in all Pennsylvania counties.9 PA One Call’s interpretation of this\nlaw did not require Palmer to be a member, so its underground pipes were not\nincluded in the PA One Call database.\n8 Pennsylvania has recognized and adopted the uniform pavement marking colors outlined in\nthe Common Ground Alliance’s Best Practices Guide for underground piping or other utility assets.\n9 See Pennsylvania Statutes, Title 73 P.S. Section 176 et. Seq.\n6\n\n<<<PAGE 18>>>\n\nPipeline Investigation Report\nReport Number PIR-25-01\nAfter the accident, the NTSB interviewed UGI crewmembers about the 2021\nreplacement of the Building 2 servic","truncated":true,"body_characters":238207}