# NTSB Safety Recommendation P-26-004 - **operation:** document - **citation:** P-26-004 - **title:** NTSB Safety Recommendation P-26-004 - **source type:** guidance - **agency:** National Transportation Safety Board - **status:** guidance - **official:** true - **published on:** 2026-03-26 - **effective on:** 2026-03-26 - **summary:** TO ATMOS ENERGY CORPORATION: Update your companywide leak management program procedures to require weekly monitoring of nonhazardous (grade 2 or grade 3) belowground leaks identified in locations with adverse-soil conditions (such as water-saturated soil, flooding, drought, frozen ground, or settlement). - **machine formats:** - **json:** https://regulus.evalyn.ai/document/ntsb-recommendation-p-26-004.json - **markdown:** https://regulus.evalyn.ai/document/ntsb-recommendation-p-26-004.md - **app url:** https://regulus.evalyn.ai/document/ntsb-recommendation-p-26-004 - **source url:** https://data.ntsb.gov/carol-main-public/sr-details/P-26-004 **body:** NTSB safety recommendation P-26-004. TO ATMOS ENERGY CORPORATION: Update your companywide leak management program procedures to require weekly monitoring of nonhazardous (grade 2 or grade 3) belowground leaks identified in locations with adverse-soil conditions (such as water-saturated soil, flooding, drought, frozen ground, or settlement). Priority: CLASS II Overall Status: Open - Initial Response Received Issued Date: 2026-03-26 Adopted Date: 2026-03-12 Synopsis: This report discusses the January 2024 natural gas-fueled explosions and fires at two separate homes in Jackson, Mississippi, which occurred 3 days apart, collectively resulting in one injury, one fatality, and three destroyed homes. Safety issues identified in this report include compression coupling leaks, insufficient leak management program, inadequate distribution integrity management program, ineffective public awareness program, and absence of natural gas detection alarms in buildings. Probable Cause: The National Transportation Safety Board determines that the probable cause of the two explosions at two separate homes in Jackson, Mississippi, was the service-line pipes partially pulling out of the compression couplings, likely because of soil movement (shrinking and swelling), creating natural gas leaks that Atmos Energy Corporation identified and left unrepaired for at least 8 weeks, which enabled gas to migrate to the nearby homes and ignite. Contributing to Atmos Energy Corporation’s failure to prevent the accidents were the operator’s: (1) insufficient leak management program, which did not determine appropriate monitoring timelines for leaks in adverse-soil conditions; (2) ineffective public awareness program, which did not adequately educate the public or emergency response officials on how to respond to a suspected natural gas leak; and (3) inadequate integrity management program, which did not appropriately assess and address risk in its Mississippi Division pipeline system. Ntsbnumber: PLD24FR003 Report Number: PIR-26-01 Addressee Name: ATMOS Energy Corporation Addressee Status: Open - Initial Response Received Addressee Organization Type: P-Private Industry Communication Date: 2026-03-26 Communication Type: Transmittal Letter Communication Contents: The National Transportation Safety Board (NTSB) is an independent federal agency charged by Congress with investigating every civil aviation accident in the United States and significant accidents in other modes of transportation—railroad, highway, marine, and pipeline. We determine the probable cause of the accidents and issue safety recommendations aimed at preventing future accidents. In addition, we carry out special studies concerning transportation safety and coordinate the resources of the federal government and other organizations to assist victims and their family members affected by major transportation disasters. We are providing the following information to urge Atmos Energy Corporation to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter also includes information about our March 12, 2026, report, Atmos Energy Corporation Natural Gas-Fueled Home Explosions and Fires, Jackson, Mississippi, January 24, 2024, and January 27, 2024, NTSB/PIR-26-01. The details of this accident investigation and the resulting safety recommendations may be found in the attached report, which can also be accessed at http://www.ntsb.gov. As a result of this investigation, we identified the following safety issues: • Compression coupling leaks that the natural gas distribution operator had identified and left unrepaired. • Insufficient leak management program, which did not determine appropriate monitoring timelines for leaks in adverse-soil conditions. • Ineffective public awareness program, which did not adequately educate the public or emergency response officials on how to respond to a suspected natural gas leak. • Inadequate distribution integrity management program, which did not appropriately assess and address risk in its pipeline system. • Absence of natural gas detection alarms in buildings, which left occupants vulnerable to the dangers of unrecognized gas leaks. Accordingly, the NTSB makes the following safety recommendations to Atmos Energy Corporation (additional information regarding this recommendation can be found in the noted section of the report): • Develop and implement a program to locate and replace all mechanical couplings and mechanical joints located in expansive soils that are not resistant to pipe pullout with couplings and joints developed specifically for those conditions. The program should establish and make public the project milestones and timeline. (P-26-3) (See section 2.2.) • Update your companywide leak management program procedures to require weekly monitoring of nonhazardous (grade 2 or grade 3) belowground leaks identified in locations with adverse-soil conditions (such as water-saturated soil, flooding, drought, frozen ground, or settlement). (P-26-4) (See section 2.3.) • After completing the action described in P-26-4, implement a training program to maintain employee and contractor proficiency on the updated procedures. (P-26-5) (See section 2.3.) • Develop and implement a program to provide more frequent training to emergency response officials in all the distribution areas that you serve, including training on how to respond to natural gas-leak calls, and monitor the program for effectiveness. (P-26-6) (See section 2.4.) • Require your technicians who identify but do not repair a belowground natural gas leak to immediately notify people near the unrepaired leak that (1) the hazard potential of a leak can change over time, and (2) they should evacuate and then call 9 1 1 and Atmos Energy Corporation every time they smell natural gas odorant. (P-26-7) (See section 2.4.) • Develop and implement a program to proactively identify and collect missing service-line information for all your operating divisions. The program should (1) identify one or more methods for gaining additional system data and (2) establish and make public the milestones and timeline for acquiring the unknown system data. (P-26-8) (See section 2.5.) • Transition from a relative-risk model to a probabilistic distribution integrity management risk model. (P-26-9) (See section 2.5.) • Develop and implement a program that makes natural gas alarms available to members of the public who reside in your distribution areas. (P-26-10) (See section 2.6.) The NTSB is vitally interested in these recommendations because they are designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendations by number (Safety Recommendation P-26-3 through -10). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, please e mail us at the same address for instructions on how to send larger documents. Please do not submit both an electronic copy and a hard copy of the same response. All communications regarding safety recommendations are stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. In the likely event that your organization uses auto generated and/or preformatted confidentiality statements on letterhead or outgoing e-mails, please include a statement in your letter indicating that the information can be publicly released. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov. From Pipeline Investigation Report PIR-26-01 “Atmos Energy Corporation Natural Gas Fueled Home Explosions and Fires Jackson, Mississippi January 24, 2024, and January 27, 2024” published on March 26, 2026: 2.3 Insufficient Leak Management Program Leak Repair and Leak Reevaluation The leaks Atmos identified and classified on Bristol Boulevard (a grade 2 leak) and Shalimar Drive (a grade 3 leak) became hazardous before Atmos’s leak management program procedures required them to be reevaluated or repaired. Atmos’s Mississippi procedures required a grade 2 leak to be reevaluated at least once every 6 months and repaired within one calendar year (but no later than 15 months). The accident on Bristol Boulevard occurred about 2 months after Atmos identified the grade 2 leak there, which was about 4 months before Atmos procedures required its technicians to reevaluate the leak and about 13 months before Atmos procedures required its technicians to repair it. Atmos’s Mississippi procedures required a grade 3 leak to be reevaluated during the next scheduled survey or within 15 months, whichever came first, and repaired or cleared within 36 months. The accident on Shalimar Drive occurred about 2 months after Atmos identified the grade 3 leak there, which was about 13 months before Atmos procedures required its technicians to reevaluate the leak and about 34 months before Atmos procedures required its technicians to repair or clear it. After the two accidents, Atmos updated its companywide leak management program to reduce the reevaluation and repair timelines for all nonhazardous natural gas leaks to every 30 days and within 6 months, respectively. Leak Monitoring Between November 2023 and January 2024, when weather conditions in Jackson adversely affected the soil, changing the natural gas migration patterns of at least 2 of the 289 open (unrepaired) leaks in the city (leaks open on the day of the Bristol Boulevard accident), Atmos’s Mississippi leak management program procedures did not prompt employees to monitor the open leaks. However, unlike Atmos’s Mississippi procedures, Atmos’s procedures for classif Addressee Organization Type: P-Private Industry Communication Date: 2026-06-24 Communication Type: Official Correspondence Communication Contents: -From John McDill, Senior Vice President Utility Operations: Atmos Energy has implemented enhancements to our companywide leak management and monitoring practices that address nonhazardous belowground leaks. Atmos Energy shares the objective of proactively managing leak risk, particularly where environmental conditions may influence leak behavior. That is why we have made significant enhancements to our leak management program and processes and have also made specific enhancements to address the impact of weather and soil conditions on our assets. Our comprehensive approach includes enhanced monitoring of our operating system, accelerating the repair of leaks after detection, and periodically monitoring their status until repaired. These proactive leak management measures exceed current regulatory requirements and align with the intent of relevant safety portions of PHMSA’s May 2023, leak detection and repair proposed rule, PHMSA-2021-0039. Specifically, Atmos Energy has implemented the following: • Enhanced Leak Monitoring Frequencies – In fiscal year 2025, we used a variety of technologies to survey more than 80,000 miles of pipeline assets, a 43% increase over the prior fiscal year. A majority of our pipeline miles are surveyed at least annually, and that includes areas or materials identified as higher relative risk. We plan to continue to utilize enhanced survey frequencies which allow us to increase the knowledge about our operating system and take risk-appropriate measures based on the data. • Enhanced Leak Monitoring Technologies – In addition to increasing leak survey frequencies enterprise wide, we have also continued to deploy Advanced Mobile Leak Detection (AMLD) technology in conjunction with traditional leak survey technologies. Today we operate a fleet of 25 AMLD units that continuously monitor our operating system. • Accelerated Leak Re-evaluation Cadence – Grade 2 and Grade 3 leaks are those that are recognized as being non-hazardous at the time of detection and are scheduled for repair. We have enhanced our leak monitoring efforts so that all belowground Grade 2 and Grade 3 leaks are re-evaluated within every 30 days until repaired, a timeframe that exceeds regulatory requirements. • Expedited Leak Repairs – We have continued to decrease the average time it takes to repair a below ground leak once it is detected. A Grade 1 leak requires immediate repair or continuous action until the conditions are no longer hazardous. For belowground Grade 2 and Grade 3 leaks, Atmos Energy’s average repair time is approximately 35 days, a timeframe that exceeds regulatory requirements. • Leak Alert Process – Most recently, Atmos Energy has developed and is implementing across the company a leak alert system that allows us to take action based on data regarding clusters of leak activity. The leak alert system triggers alerts when below ground leaks exceed a predetermined threshold in dynamic geographical areas. These alerts are provided to our local operating teams. The local operating teams review the data and develop an appropriate response. This proactive approach brings additional rigor to further enhance safety actions as needed based on the operational review. These proactive and comprehensive measures to leak management are driving meaningful safety outcomes. These measures allow us to enhance our knowledge about our operating system and take data-driven, risk-appropriate measures to improve safety. They also allow us to gather data that feeds into our other distribution integrity programs, as shown in the figure in response to Recommendation P-26-3. While the measures described above are a comprehensive approach to addressing the risk of leaks on our system regardless of soil condition, Atmos Energy has also made proactive enhancements specifically related to soil conditions: • Soil Stability Alert System (SSAS) – Atmos Energy has implemented a dynamic Soil Stability Alert System (SSAS) in Texas, Louisiana and Mississippi and will complete its implementation across the rest of our service territory in 2026. This system considers changes in soil moisture relative to the underlying soil type and provides notices of areas where rain or other weather conditions could be causing soils to shrink or swell/expand and increase the potential for pipe stress and susceptibility for leakage. SASS uses soil moisture data that is updated daily to capture the impact of current weather events. For alerts that are generated, Atmos Energy performs a review of our assets in the area identified, including high-relative risk areas identified by our Distribution Integrity Management Plan. Based on this review, we deploy leak survey resources to assess the area and expedite the repair of any below ground leak found. Atmos Energy’s current leak management practices—frequent re-evaluations, accelerated repairs, enhanced survey coverage, and weather-informed alerts—continue to exceed regulatory requirements while maintaining alignment with the intent of the regulations. We believe our comprehensive, proactive leak-management program fulfills the intent of this Recommendation. For that reason, we ask the NTSB to find this response satisfactory and close this Recommendation as acceptable. - **truncated:** false - **body characters:** 15604