NTSB Safety Recommendation P-26-010

NTSB safety recommendation P-26-010.

TO ATMOS ENERGY CORPORATION: Develop and implement a program that makes natural gas alarms available to members of the public who reside in your distribution areas.

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: 2.6 Absence of Natural Gas Detection Alarms in Buildings The Bristol Boulevard accident home and the Shalimar Drive accident home did not have natural gas alarms installed. For nearly 50 years, the NTSB has been recommending natural gas alarms for the early detection of natural gas leaks. In the West Reading accident, several candy factory employees told the NTSB that they had smelled natural gas odorant and did not call 9 1 1 or the gas company but stayed in the building until the explosion occurred. Some of the employees inquired with their managers about what to do, and their managers were equally unaware of the actions to take during a suspected natural gas leak. In the two Jackson accidents, and in many of the pipeline accidents the NTSB has investigated for the last 5 decades, people smelled natural gas odorant and either did not know what actions to take, or they knew the actions necessary to address a potential natural gas emergency but did not execute them. Natural gas distribution pipeline operators must educate the public on pipeline safety through public awareness programs. It is also necessary, however, to have safeguards in place when members of the public (1) smell natural gas odorant and do not take the appropriate safety actions and (2) do not smell natural gas odorant, as was the case in the NTSB investigation of the Dallas accident, and therefore do not take appropriate safety actions. Footnote: The NTSB’s Dallas investigation determined that the occupants in the accident homes did not smell natural gas odorant because it was absorbed and depleted in the soil. Natural gas alarms are safeguards in protecting the public, which is why the NTSB has recommended their installation after many of our pipeline accident investigations. The NTSB found that natural gas alarms likely would have prevented or reduced the consequences of the Dallas and West Reading accidents, and the evidence in this investigat

Addressee Organization Type: P-Private Industry

Communication Date: 2026-06-05

Communication Type: Recommendation Mention

Communication Contents: Atmos Energy Corporation Natural Gas–Fueled Home Explosion Pipeline Investigation Report PIR-26-03 published on June 5, 2026: Analysis The explosion and fire occurred after natural gas leaked from a fractured buried main, migrated through an uncapped underground sewer lateral, entered the accident home, and reached an explosive concentration near an unknown ignition source. The investigation did not identify issues with gas pressures in the area of the leak or the timeliness or efficacy of the local emergency response agencies. Postaccident bar-hole testing and excavations found only one source of natural gas: a leak in the gas main near a valve box on the eastern edge of the construction site. On-site examinations of the main found that it was fractured around most of its circumference with a thin strip of metal at the top (12 o’clock position) joining the southern section of pipe to the section still threaded into the valve body. This indicates tension—a stretching force—at the bottom of the pipe along its long axis. Tension along the bottom of the pipe is consistent with a bending stress created by an external downward force. Based on information provided to Atmos by the construction superintendent, a cement truck ran over a valve box at the leak’s location immediately before he heard and smelled natural gas being released. The investigation did not identify another plausible external force that could have damaged the main. The Materials Laboratory examination of the main found fracture characteristics typical of fast crack growth and no signs of significant corrosion or preexisting structural damage that could have contributed to the failure. The fracture was therefore consistent with a sudden application of force by the valve box to the main. Based on the fracture’s location, timing, and fast-cracking characteristics, the valve box transmitted part of the cement truck’s weight to the gas main, causing the main to fracture and leak. Examination of the gas main and valve box involved in this accident found coal tar coating the main and deposited on the bottom edge of the valve box. This indicates that the valve box was in contact with the main. The presence of coal tar alone does not indicate when the contact occurred, but the evidence is consistent with the valve box being installed in contact with the main and therefore able transmit the cement truck’s weight directly to the main near the fracture’s location. Federal regulations at 49 CFR 192.181(c)(3) require that valve boxes not be installed in a manner that transmits external loads to mains, and valve boxes are normally installed with a buffer of soil or other protection between the valve box and the assets immediately below. For example, Atmos’s newer valve boxes are installed with support and base pads to prevent load transmission. However, Atmos was not actively replacing cast iron valve boxes with this newer design. Further, the maintenance crew that removed and reinstalled the valve box about 2 months before the accident did not have a specific standard to follow for reinstalling cast iron valve boxes other than an expectation that the top of the valve box be level with the grade. The lack of a standard likely led to the common reinstallation of valve boxes in contact with mains, as described by an Atmos vice president of operations. If Atmos had adopted either a standard for safely installing cast iron valve boxes or a policy of replacing cast iron valve boxes with the newer design, the protective buffer of soil or support pad would have reduced the load transmitted to the pipe on the day of the accident. There is not enough evidence to determine whether a buffer or pad would have prevented the accident, but it would have made the infrastructure more resilient. Atmos has not reported making changes to its valve box installation practices. After the main fractured, gas propagated undetected through an uncapped underground sewer lateral into the sewer system and then into the accident home, where it reached an explosive concentration. The gas in the sewers remained undetected because Atmos personnel did not test the atmosphere in the sewers prior to the explosion. For about 35 minutes, most of the time between the initial leak and the explosion, there was only one Atmos employee on the scene: an experienced senior service technician. He was equipped with a CGI and checked nearby storm drains for the presence of gas, which was one step in Atmos’s subsurface leak investigation procedure. During his interview with the NTSB, he described planning to check the sewers, another required step, but said that he had already confirmed that there was no threat to life or property. His activities after checking the storm drains are also consistent with a belief that he had finished assessing the risk posed by the leak: he switched to the non-safety-critical work of recording billing information for the damage. The investigation did not find evidence of a natural gas alarm in the accident home, which did not have gas service but was still impacted by a leak from a gas main. It is likely that a natural gas alarm would have provided the home’s occupants with warning of accumulating natural gas and given them an opportunity to evacuate before the explosion. The NTSB has advocated wider installation and use of natural gas alarms for nearly 50 years, including following the investigation into a pair of 2024 home explosions in Jackson, Mississippi, that involved Atmos assets. As a result of that investigation, the NTSB reiterated a recommendation to the 50 states, the Commonwealth of Puerto Rico, and the District of Columbia: Require the installation of natural gas alarms that meet the specifications of National Fire Protection Association 715 in businesses, residences, and other buildings where people congregate that could be affected by a natural gas leak. (P-25-5) Footnote: See CAROL for the complete history and current status of this recommendation. The NTSB also recommended that Atmos “develop and implement a program that makes natural gas alarms available to members of the public who reside in its distribution areas” (P-26-10).11F Footnote: See CAROL for the complete history and current status of this recommendation.

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: Natural gas alarms are commercially available to the public. Atmos Energy’s public awareness program involves informing members of the public in our distribution areas about natural gas alarms, including their commercial availability and their role as an additional tool for detecting a gas leak. Atmos Energy’s program also involves ongoing engagement with numerous industry stakeholders on the issue of how natural gas alarms fit within overall natural gas related safety communications and standards. As a member of the American Gas Association, Atmos Energy notes that organization’s July 7, 2025 response to the NTSB’s April 8, 2025 recommendation regarding alarms, including the following: AGA recognizes that natural gas alarms can be a useful tool to help building occupants identify the presence of natural gas. However, odorant, the pungent and memorable smell of rotten eggs, remains the primary means of detecting the presence of combustible levels of natural gas in businesses, residences, and other places of human congregation. Natural gas alarms may complement but do not replace odorization as the most effective means of identifying the presence of natural gas. The potential safety benefits of natural gas alarms, as well as their reliable performance, are based upon many considerations, including, but not limited to, the configuration of the premises, air flow, proper installation and maintenance in accordance with manufacturer instructions, and compliance with relevant local code requirements. Unlike odorant, these factors are outside the jurisdiction and control of natural gas distribution utilities. Indeed, many members educate and inform their customers of the availability of methane detectors, however there remains some concern regarding reliable performance of these devices based on the considerations noted above. It is precisely for this reason that other in-home/in-building safety devices such as smoke alarms and carbon monoxide alarms are included in life safety, fire safety, and building construction national consensus standards. These standards are developed by subject matter experts and incorporated by reference into state and municipal codes. AGA understands the NTSB’s focus on natural gas detectors and will send additional communications to its member companies, providing them an update on how voluntary consensus standards are addressing natural gas alarms and to encourage members to consider whether, when, and how to communicate the potential safety benefits of natural gas alarms when installed and maintained consistent with manufacturer and local code requirements. To further this commitment, NFPA 715, Standard for the Installation of Fuel Gases Detection and Warning Equipment, is the national consensus standard that directly addresses natural gas alarms. It includes provisions addressing installation, power source, and maintenance of natural gas alarms, among other issues. AGA is a member of the consensus committee that developed NFPA 715 and voted to approve the prior version, NFPA 715 (2023), and the most recently published version, NFPA 715 (2026). NFPA 715 has been proposed for incorporation by reference into model codes addressing life safety, fire safety, and building construction. These codes are developed to improve building and occupant safety and are relied upon by builders, plumbers, and electricians when constructing or renovating buildings. State and municipal authorities adopt these codes to help ensure the buildings and building occupants in their jurisdictions are safe, and state and municipal building inspectors rely on these codes when enforcing building construction requirements. Once natural gas alarms are more widely adopted by state and municipal life safety, fire safety, and building codes, natural gas alarms will likely be more commonly used. AGA will continue to engage in voluntary national consensus standards that develop model life safety, fire safety, building construction, and natural gas alarm installation standards, which are currently addressing the safe and effective use of natural gas alarms in commercial buildings and residences. Consistent with the AGA’s commentary, Atmos Energy (1) educates the public in Atmos Energy’s service territories regarding natural gas safety topics including providing important information about natural gas safety alarms; (2) continues to engage with stakeholders regarding the development of natural gas alarms as an important safety tool in the industry. Informing the public. Atmos Energy provides information on natural gas alarms through its public safety communications, including its natural gas safety guide and its website. This information alerts the public to the availability of residential methane detectors as an additional means of detection, while continuing to emphasize critical information about using all senses to detect a gas leak. Atmos Energy also communicates that alarms must be selected, installed, and maintained in accordance with manufacturer instructions and other standards, such as NFP Stakeholder engagement. Beyond informing the public about the availability of natural gas alarms – and the importance of following standards when using them – Atmos Energy has engaged for many years with a variety of industry stakeholders to continue advancing natural gas safety, including addressing the role of natural gas alarms. • American Gas Association – Atmos Energy is a member of the American Gas Association and follows closely the AGA’s work related to natural gas alarms. As described in the AGA’s response excerpted above, AGA is a member of the consensus committee that developed NFPA 715 and voted to approve the most recently published version, NFPA 715 (2026). Atmos Energy will continue to coordinate closely with the AGA regarding its efforts to engage in voluntary national consensus standards addressing the safe and effective use of natural gas alarms in commercial buildings and residences. • International Code Council (“ICC”) – Atmos Energy continues to monitor the ICC’s consideration of provisions related to gas detectors in its model building codes. Most recently, the ICC Residential Committee considered providing guidance to jurisdictions considering how to implement the installation of fuel gas alarms on requirements that are consistent with best industry practices and the NFPA 715 Standard. • GTI Energy – Atmos Energy contributes to a voluntary industry collaborative that GTI Energy administers. GTI Energy continues to provide technical input to help establish nationally recognized standards for residential methane detectors (RMDs) and has completed a field testing program to evaluate performance of off-the-shelf detectors in a variety of residential settings. The testing and benchmarking provided a better understanding of accuracy of detection levels, airborne chemical interference, and hurdles to home deployment. • Local Engagement – Atmos Energy has also engaged with and is listening to policy officials and local first responders in its service territories to help inform these stakeholders of the importance of following manufacturing and installation standards (including NFPA 715) regarding natural gas alarms as well as how such alarms fit within overall natural gas safety information for the public. Atmos Energy’s programmatic approach to natural gas alarms is ongoing and will continue to focus on informing the public of the commercial availability of natural gas alarms – and the importance of using them in accordance with industry standards – as well as engaging with stakeholders. Accordingly, we ask that the NTSB close this Recommendation as acceptable.