{"operation":"document","citation":"PLD25FR001","title":"Enbridge Inc. Natural Gas-Fueled Home Explosion","source_type":"incident","agency":"National Transportation Safety Board","status":"current","official":true,"published_on":"2026-04-08","effective_on":"2024-11-06","summary":"Accident. in South Jordan, UT, USA. on 2024-11-06. Enbridge Gas. Leak/explosion/fire","machine_formats":{"json":"https://regulus.evalyn.ai/document/ntsb-case-pld25fr001.json","markdown":"https://regulus.evalyn.ai/document/ntsb-case-pld25fr001.md"},"app_url":"https://regulus.evalyn.ai/document/ntsb-case-pld25fr001","source_url":"https://www.ntsb.gov/investigations/Pages/PLD25FR001.aspx","body":"NTSB investigation PLD25FR001.\n\nEvent Type: Accident\n\nEvent Date: 2024-11-06\n\nEvent City: South Jordan\n\nEvent State Or Region: UT\n\nEvent Country: USA\n\nPipeline Operator: Enbridge Gas\n\nPipeline Type: Distribution\n\nAccident Type: Leak/explosion/fire\n\nCompletion Status: Completed\n\nReport Number: PIR2602\n\nReport Date: 2026-03-31\n\nProbable cause: The National Transportation Safety Board determines the probable cause of the explosion was a through-wall crack that formed in a 4-inch diameter 1976 polyethylene Aldyl A gas distribution main due to rock impingement, allowing natural gas to leak, migrate about 150-ft, and accumulate in a home where it was ignited by the furnace. Contributing to the severity were ineffective safeguards to mitigate hazards presented by the leak, such as the lack of natural gas alarms that could have provided an early warning to occupants and prompted evacuation.\n\nTier1Name: Post-release\n\nTier2Name: Fire/explosion (post-release)\n\nFinding Tier1Name: Pipeline\n\nFinding Tier2Name: Pipeline structure\n\nFinding Tier3Name: Pipe\n\nFinding Modifier Name: Failure\n\nFinding Report Text: Pipeline - Pipeline structure - Pipe - Failure\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 November 6, 2024, about 3:09 p.m., a natural gas–fueled explosion fatally injured one person and destroyed a home in South Jordan, Utah. Several nearby residences were damaged, and families displaced. The South Jordan Fire Department responded, arriving on scene about 3:15 p.m. Technicians from Enbridge Inc. (Enbridge) subsidiary Enbridge Gas Utah, the natural gas service provider to the home, responded and arrived on scene about 3:45 p.m.2 Enbridge isolated the leak about 12:16 p.m. on November 7. At the time of the explosion, conditions were daylight and clear; the temperature was 41°F with no precipitation.\n\nWhat We Found\nWe determined the probable cause of the explosion was a through-wall crack that formed in the 1976 vintage 4-inch-diameter Aldyl A polyethylene gas distribution main from a rock impingement, allowing natural gas to leak, migrate about 150 feet, and accumulate in a home, where it was ignited by the home’s furnace. Contributing to the severity were insufficient safeguards to mitigate hazards presented by the leak.\n\nLessons Learned\nThe events leading up to the home explosion in South Jordan illustrate how natural gas alarms could mitigate the consequences of gas leaks. Aldyl A piping manufactured before 1983 is prone to cracking and needs to be carefully assessed to protect public health and safety. Aldyl A pipeline failures are difficult to predict, and natural gas alarms can help safeguard members of the public who reside in areas with natural gas distribution systems. Natural gas alarms have been available for several years and can alert homes and businesses of gas leaks even when natural gas odorant is depleted in the natural gas. Natural gas alarms provide an early warning to building occupants before the gas concentrations reach an explosive level and alert occupants to evacuate the building. For more, see NTSB Safety Alert SA-098, Natural Gas Alarms Save Lives.\n\nTo address the threats identified during the investigation, Enbridge initiated several changes to their procedures and evaluation of Aldyl A pipe. Enbridge Gas Utah updated their risk assessment protocols for Aldyl A piping and completed leak surveys using an advance mobile leak detection system of 100% of the Aldyl A gas piping with the threat of cracking. All immediate leaks were evaluated and repaired. Enbridge has committed to an increase in its capital budget for risk-informed targeted replacement of high-risk Aldyl A piping. Their leak history, leak survey results, and repair data will be used to refine ongoing leak survey frequency and better inform asset replacement decisions.\n\nTo decrease the risk to the first responders and nearby residents and address the extended response time to locate the gas leak in South Jordan, Enbridge revised two standard practices specific to Enbridge Gas Utah operations for the investigation of leaks. One change refocused response resources on all gas assets in the area to improve the efficiency of the response and to isolate leaks as quickly as possible, and the other change requires bar hole testing of the perimeter of the structure and over all the gas assets in the area. To promote the installation of natural gas alarms, Enbridge has partnered with the American Red Cross in the Salt Lake City area and has made natural gas alarms/carbon monoxide detectors available at a recent event. In partnership with the city of South Jordan, Enbridge is also making additional natural gas alarms/carbon monoxide detectors available to residents at an upcoming event in May.\n\nPIR-26-02\n<<<PAGE 1>>>\n\nPipeline Investigation Report\nPIR-26-02\nIssued: March 31, 2026 Pipeline Investigation Report: PIR-26-02\nEnbridge Inc. Natural Gas–Fueled Home\nExplosion and Fatality\nLocation South Jordan, Utah\nDate November 6, 2024\nSystem type Natural gas distribution\nAccident type Rupture/release\nPipeline operator Enbridge Gas Utah\nHazardous materials Natural gas\nFatalities 1\nInjuries 0\nProperty damage $1,030,443\nSummary\nOn November 6, 2024, about 3:09 p.m., a natural gas–fueled explosion fatally\ninjured one person and destroyed a home in South Jordan, Utah.1 Several nearby\nresidences were damaged, and families displaced. (See figure 1.) The South Jordan Fire\nDepartment responded, arriving on scene about 3:15 p.m. Technicians from Enbridge\nInc. (Enbridge) subsidiary Enbridge Gas Utah, the natural gas service provider to the\nhome, responded and arrived on scene about 3:45 p.m.\n2 Enbridge isolated the leak\nabout 12:16 p.m. on November 7. At the time of the explosion, conditions were daylight\nand clear; the temperature was 41°F with no precipitation.\n1 All times in this report are local. (b) Visit ntsb.gov to find additional information in the public docket for\nthis National Transportation Safety Board (NTSB) accident investigation (case number PLD25FR001),\nincluding detailed factual reports about the circumstances of the accident.\n2 In June 2024, Enbridge purchased local gas distribution company Questar Gas from Dominion\nEnergy, Inc. and renamed it Enbridge Gas Utah, Enbridge Gas Wyoming, and Enbridge Gas Idaho.\nEnbridge subsidiary, Enbridge Gas Utah, provided natural gas service to the home. This report uses the\ncurrent company name, Enbridge, throughout.\n1\n\n<<<PAGE 2>>>\n\nPipeline Investigation Report\nPIR-26-02\nFigure 1. The scene on the day of the accident. (Drone photography courtesy of the South\nJordan Police Department.)\n1.1 Before the Accident\nDuring interviews conducted by the Utah Deputy State Fire Marshal, the residents\nof the house reported the following observations regarding the days leading up to the\nexplosion:\n• Some family members felt dizzy, had flu-like symptoms, and had\nheadaches.\n• On November 3, the water heater in the basement was not working\ncorrectly.\n• On November 5, they attempted to troubleshoot the water heater but\nwere unable to relight the pilot light.\n• During the evening on November 5, one of the residents lit a candle,\nobserved an unusually high flame, and quickly extinguished the flame.\nThe residents told the fire marshal they were aware of what odorized natural gas\nsmelled like and did not smell any gas odor in the home before the explosion. No\n2\n\n<<<PAGE 3>>>\n\nPipeline Investigation Report\nPIR-26-02\noutside gas odors in the area were reported to the gas company before the accident.\n3\nThere were no natural gas alarms in the home.\n1.2 Accident Response\nAbout 3:09 p.m. on November 6, 2025, the 911 operator received the first of\nseveral calls reporting the explosion at 10593 S 3210 W (street). About 6 minutes later, at\n3:15 p.m., the fire department arrived at the accident scene. About 3:45 p.m., Enbridge\ntechnicians arrived on scene and began work to identify the location of the leak. Their\nactivities included bar hole testing in the ground around the accident scene and\npressure testing of the natural gas pipes servicing the home and the neighborhood,\nwhich continued for more than 21 hours before the location of the leak was identified.\n4\n(See figure 2.) Table 1 is a timeline of the accident response.\n3 NTSB investigators reviewed records for 1 year before the accident.\n4 Bar hole testing is a gas measurement technique in which a small-diameter hole is made in the\nground (a bar hole), a gas measurement probe is inserted into the hole, and a gas concentration\nmeasurement in the ground is obtained.\n3\n\n<<<PAGE 4>>>\n\nPipeline Investigation Report\nPIR-26-02\nFigure 2. Peak subsurface gas readings before isolation of the gas leak.\nAbout 12:16 p.m. on November 7, Enbridge technicians found a leak about 150\nfeet northeast of the home on a 4-inch-diameter Aldyl A natural gas main, which\nEnbridge also owned and operated.5 The Aldyl A gas main was manufactured and\ninstalled in 1976 and operated at a pressure of about 45 psig, below the maximum\nallowable operating pressure of 60 psig.6 The technicians removed and then replaced\nthe damaged section of the pipe.\n5 Aldyl A is the trademarked name of a polyethylene plastic gas pipeline product that was\nmanufactured by the DuPont chemical company using a proprietary polymer resin. It is no longer\nmanufactured or used in new pipelines.\n6 Psig is the abbreviation for pounds per square inch, gauge, which is the pressure measurement\nobtained by using a conventional pressure gauge.\n4\n\n<<<PAGE 5>>>\n\nPipeline Investigation Report\nPIR-26-02\nTable 1. Timeline of the accident response.\nTime Activity\nNovember 6 November 6\n3:09 p.m. The first 911 call reported an explosion at 10593 S 3210 W.\n3:15 p.m. Fire Department Engine 62 arrived on site.\n3:45 p.m. Enbridge technicians arrived on scene and began leak\ninvestigation activities.\n5:00 p.m. Enbridge began bar hole testing.\n5:45 p.m.\nto\n12:34 a.m.\n(November 7)\nEnbridge began pressure testing gas assets west (in front)\nof accident home.\nNovember 7 November 7\n12:17 a.m.\nto\nEnbridge resumed bar hole testing west of accident home.\n4:30 a.m.\n4:55 a.m.\nto\n6:33 a.m.\nEnbridge expands bar hole testing east of (behind) accident\nhome.\n12:16 p.m. Enbridge found and stopped the leak.\nAfter the explosion, Enbridge technicians found gas in the ground in front of the\nhouse and again between the accident home and the adjacent home immediately to the\nnorth. Further investigation found gas in the ground extending from the rear of the\nhouse to the location of the leak in the street to the east, behind the accident home. The\nsubsurface gas extended from the leak location below the street behind the home,\nthrough the backyard, and to the front yard of both homes (the accident home and the\nadjacent home), reaching about 250 feet from the leak. Technicians also detected gas in\nthe atmosphere of the adjacent home after the accident.\n1.3 Gas Main Examination\nExamination of the damaged pipe by the National Transportation Safety Board\n(NTSB) Materials Laboratory found crack growth that started at the inner wall of the pipe.\nThe crack growth features were traced back to a single point origin on the inner surface,\nwhich aligned longitudinally with an outer surface impingement point. (See figure 3.) The\ncrack growth region extended as much as 3.5 inches along the length of the pipe.\nFurther, flow testing of the damaged pipe in the lab measured a leak rate for natural gas\n5\n\n<<<PAGE 6>>>\n\nPipeline Investigation Report\nPIR-26-02\nequivalent of 48.7 scfm at a pressure of 43 psig (about the operating pressure at the time\nof the accident).\n7\nFigure 3. Crack origin area on inner wall of pipe.\nAldyl A piping manufactured before 1983 is prone to slow crack growth, which\nmay be initiated by rock impingement or impingements from other causes.\n8 The NTSB\ninvestigated a 2006 accident where an impingement caused a leak on a 2-inch Aldyl A\ngas main manufactured in 1976.9\n2 Analysis\nOn November 6, 2024, a natural gas–fueled home explosion fatally injured one\nresident and damaged nearby homes. A crack in the 4-inch-diameter Aldyl A gas main\nnear the home allowed natural gas to leak and fuel the home explosion.\nThe NTSB found that the crack originated on the inner surface of the pipe and\naligned directly with an oblong impression on the outer surface. Investigators\ndetermined that a rock impingement likely caused the oblong impression on the outer\nsurface of the pipe and the resulting crack. They also found that the crack growth\nfeatures indicated that the crack breached the outer surface in a single abrupt event. As\na result, the pipe rapidly transitioned from releasing no gas to releasing up to 48.7 scfm,\n7 Scfm is the abbreviation for standard cubic feet per minute, a measurement of gas flow corrected for\nstandard temperature of 60°F and absolute atmospheric pressure of 14.696 pounds per square inch.\n8 Haine, Steven. 2014. Hazard Analysis and Mitigation Report on Aldyl A Polyethylene Gas Pipelines in\nCalifornia. San Francisco, CA: California Public Utilities Commission.\n9 NTSB. 2010. Explosion, Release, and Ignition of Natural Gas, Rancho Cordova, California, December\n24, 2008. PAB-10/01. Washington, DC: NTSB.\n6\n\n<<<PAGE 7>>>\n\nPipeline Investigation Report\nPIR-26-02\nas measured in the lab.\n10 Post-explosion, subsurface gas readings showed that the\nnatural gas migrated about 150 feet from the leak location to the home. Although the\nexact timing of the leak could not be determined, the residents’ observations of physical\nsymptoms, inability to relight the basement water heater, and an unusually high candle\nflame before the accident suggest that natural gas may have been present in the home\nfor at least 3 days before the explosion. On November 6, the flammable natural gas–air\nmixture ignited in the southwest quadrant of the basement. The Utah Deputy State Fire\nMarshal identified two possible sources of the ignition: a water heater and a furnace. The\nwater heater was turned off at the control point, so the only credible ignition source was\nthe furnace.11\nBefore the accident, Enbridge had implemented safeguards to mitigate the\nconsequences of leaks, including periodic leak surveys, timely response to odor\ncomplaints, and targeted replacement projects. However, none of these strategies\nproved effective for this scenario, because of the following issues related to the\nstrategies:\n• Periodic leak surveys. Regulators require distribution leak surveys to be\nconducted every 5 years. Enbridge conducted its most recent leak survey\non April 29, 2022—two years before the accident. However, in this accident,\nthrough-wall crack propagation occurred too rapidly, causing the leak to\ngo undetected before the explosion.\n• Timely response to odor complaints. Regulators require odorization of\nnatural gas in distribution systems to help alert the public to natural gas\nleaks. During interviews conducted by investigators, the NTSB determined\nthat the local residents had not smelled natural gas odorant near the\naccident home, even though gas was determined to have permeated the\nground in the area during postaccident surveys, indicating that the odorant\nhad been stripped from the leaked natural gas that ultimately entered the\nhome.12 Although odorant can act as an early warning of a gas release to\nprevent an explosion and fire, it has been known to become depleted\nwhen traveling through soil, as it did in this accident. Previous NTSB\ninvestigations have identified occurrences of odorant depletion that\n10 The actual leak rate may have been lower, given that the pipeline was buried in soil, which would\nconstrain the pipe and provide back-pressure resistance to gas as it leaked from the pipe.\n11 The furnace control valve was found postaccident to have significant thermal damage, consistent\nwith it being the ignition source.\n12 Field testing of the gas in the distribution system after the explosion found acceptable odorant\nconcentrations.\n7\n\n<<<PAGE 8>>>\n\nPipeline Investigation Report\nPIR-26-02\nallowed natural gas leaks to go undetected, resulting in explosions in\nDallas, Texas, in 2018 and in Silver Spring, Maryland, in 2016.13,14\n• Targeted replacement projects. A 2014 California Public Utilities\nCommission study showed that the vintage of Aldyl A present in this\naccident, with stress concentrations from rock impingement, squeeze-off,\nbending, or deflection, were statistically predicted to fail between 22 and\n235 years after installation.15 Because the estimated failure time is\nimprecise (a range of more than 200 years), and because some\nenvironmental conditions—such as the locations of rocks in the backfill\nmaterial—are unknown, the Enbridge evaluation of the cracking threat to\nthe 1976 vintage Aldyl A did not accurately characterize the risk of rock\nimpingements and prevented Enbridge from identifying effective\nmitigative actions and targeted replacement projects.\n16\nEven though Enbridge worked continuously to search for the leak after the\nexplosion, it took them more than 21 hours to find and isolate the natural gas leak.\nDuring this time, the pipeline continued to leak natural gas into the ground, increasing\nthe risk to nearby residents, first responders, and others operating in the area.\nWhen an underground natural gas pipeline leak occurs rapidly, it can be difficult\nto safeguard against. Natural gas alarms can provide an early warning of natural gas\nleaks inside nearby structures and can alert the building occupants to take immediate\nsafety actions. Had in-home natural gas alarms been installed in the homes involved in\nthis accident, they would have alerted the residents to a potential problem and\nprompted them to evacuate and call 911, reducing or eliminating the fatal\nconsequences of the explosion. The NTSB has previously recommended requiring the\ninstallation of natural gas alarms in businesses, residences, and other buildings (Safety\nRecommendation P-25-05).\nProbable Cause\n13 NTSB. 2021. Atmos Energy Corporation Natural Gas–Fueled Explosion, Dallas, Texas, February 23,\n2018. PAR-21/01. Washington, DC: NTSB.\n14 NTSB. 2019. Building Explosion and Fire, Silver Spring, Maryland, August 10, 2016. PAR-19/01.\nWashington, DC: NTSB.\n15 California Public Utilities Commission 2014 Hazard Analysis and Mitigation Report On Aldyl A\nPolyethylene Gas Pipelines in California. Haine 2014.\n8\n\n<<<PAGE 9>>>\n\nPipeline Investigation Report\nPIR-26-02\nThe National Transportation Safety Board determines the probable cause of the\nexplosion was a through-wall crack that formed in the 1976 vintage 4-inch-diameter\nAldyl A polyethylene gas distribution main from a rock impingement, allowing natural\ngas to leak, migrate about 150 feet, and accumulate in a home, where it was ignited by\nthe home’s furnace. Contributing to the severity were insufficient safeguards to mitigate\nhazards presented by the leak.\nLessons Learned\nThe events leading up to the home explosion in South Jordan illustrate how\nnatural gas alarms could mitigate the consequences of gas leaks. Aldyl A piping\nmanufactured before 1983 is prone to cracking and needs to be carefully assessed to\nprotect public health and safety. Aldyl A pipeline failures are difficult to predict, and\nnatural gas alarms can help safeguard members of the public who reside in areas with\nnatural gas distribution systems. Natural gas alarms have been available for several\nyears and can alert homes and businesses of gas leaks even when natural gas\nodorant is depleted in the natural gas. Natural gas alarms provide an early warning to\nbuilding occupants before the gas concentrations reach an explosive level and alert\noccupants to evacuate the building. For more, see NTSB Safety Alert SA-098, Natural\nGas Alarms Save Lives.\nTo address the threats identified during the investigation, Enbridge initiated\nseveral changes to their procedures and evaluation of Aldyl A pipe. Enbridge Gas\nUtah updated their risk assessment protocols for Aldyl A piping and completed leak\nsurveys using an advance mobile leak detection system of 100% of the Aldyl A gas\npiping with the threat of cracking. All immediate leaks were evaluated and repaired.\nEnbridge has committed to an increase in its capital budget for risk-informed\ntargeted replacement of high-risk Aldyl A piping. Their leak history, leak survey\nresults, and repair data will be used to refine ongoing leak survey frequency and\nbetter inform asset replacement decisions.\nTo decrease the risk to the first responders and nearby residents and address\nthe extended response time to locate the gas leak in South Jordan, Enbridge revised\ntwo standard practices specific to Enbridge Gas Utah operations for the investigation\nof leaks. One change refocused response resources on all gas assets in the area to\nimprove the efficiency of the response and to isolate leaks as quickly as possible, and\nthe other change requires bar hole testing of the perimeter of the structure and over\nall the gas assets in the area. To promote the installation of natural gas alarms,\nEnbridge has partnered with the American Red Cross in the Salt Lake City area and\nhas made natural gas alarms/carbon monoxide detectors available at a recent event.\nIn partnership with the city of South Jordan, Enbridge is also making additional\n9\n\n<<<PAGE 10>>>\n\nPipeline Investigation Report\nPIR-26-02\nnatural gas alarms/carbon monoxide detectors available to residents at an upcoming\nevent in May.\nThe NTSB is an independent federal agency charged by Congress with investigating\nevery civil aviation accident in the United States and significant events in the other modes\nof transportation—railroad, transit, highway, marine, pipeline, and commercial space. We\ndetermine the probable causes of the accidents and events we investigate and issue\nsafety recommendations aimed at preventing future occurrences. In addition, we conduct\ntransportation safety research studies and offer information and other assistance to family\nmembers and survivors for each accident or event we investigate. We also serve as the\nappellate authority for enforcement actions involving aviation and mariner certificates\nissued by the Federal Aviation Administration (FAA) and US Coast Guard, and we\nadjudicate appeals of civil penalty actions taken by the FAA.\nThe NTSB does not assign fault or blame for an accident or incident; rather, as specified\nby NTSB regulation, “accident/incident investigations are fact-finding proceedings with\nno formal issues and no adverse parties … and are not conducted for the purpose of\ndetermining the rights or liabilities of any person” (Title 49 Code of Federal\nRegulations section 831.4). Assignment of fault or legal liability is not relevant to the\nNTSB’s statutory mission to improve transportation safety by investigating accidents and\nincidents and issuing safety recommendations. In addition, statutory language prohibits\nthe admission into evidence or use of any part of an NTSB report related to an accident in\na civil action for damages resulting from a matter mentioned in the report (Title 49 United\nStates Code section 1154(b)).\nFor more detailed background information on this report, visit the NTSB Case Analysis\nand Reporting Online (CAROL) website and search for NTSB accident ID PLD25FR001.\nRecent publications are available in their entirety on the NTSB website. Other information\nabout available publications also may be obtained from the website or by contacting—\nNational Transportation Safety Board\nRecords Management Division, CIO-40\n490 L’Enfant Plaza, SW\nWashington, DC 20594\n(800) 877-6799 or (202) 314-6551\n10","truncated":false,"body_characters":23687}