NTSB Safety Recommendation P-26-002

NTSB safety recommendation P-26-002.

TO THE PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION: Issue an advisory bulletin urging operators to adopt probabilistic risk models for distribution integrity management where appropriate.

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: PHMSA

Addressee Status: Open - Initial Response Received

Addressee Acronym: PHMSA

Addressee Organization Type: G-Federal Government

Communication Date: 2026-03-26

Communication Type: Transmittal Letter

Communication Contents: This letter provides information about the National Transportation Safety Board’s (NTSB) 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 recommendation to the Pipeline and Hazardous Materials Safety Administration (additional information regarding this recommendation can be found in the noted section of the report): • Issue an advisory bulletin urging operators to adopt probabilistic risk models for distribution integrity management where appropriate. (P 26 2) (See section 2.5.) In addition, the NTSB reiterates the following recommendations to the Pipeline and Hazardous Materials Safety Administration: • Evaluate 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) (See section 2.5.) • Identify effective means for natural gas distribution pipeline operators to communicate with people who live, work, or congregate within the coverage area of a natural gas distribution pipeline system and implement a plan to help operators drive continuous improvement in public awareness of natural gas safety. (P 25 3) (See section 2.4.) 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-26-2, Safety Recommendation P-21-2, and Safety Recommendation P-25-3). 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. 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: Inadequate Distribution Integrity Management Program System Data As discussed in 1.7.1.2, over 15 years ago, the Pipeline and Hazardous Materials Safety Administration introduced distribution integrity management requirements to enhance safety by identifying and reducing pipeline integrity risks. The first required element for natural gas distribution pipeline integrity management programs is system data (or system knowledge), and Atmos lacked system data for its Mississippi Division. After the Jackson accidents, Atmos told the NTSB that it did not have service-line installation records for over 63% of the service lines in its Mississippi Division. Therefore, at the time of the accidents, Atmos did not have system data for over 193,024 of the 306,387 service lines in its Mississippi Division, including the accident service lines. Atmos’s lack of system data for its Mississippi Division affected its leak management program and its risk model. The lacking system data affected Atmos’s leak management program because, despite Atmos’s knowledge of the threat of compression coupling failure in expansive-soil environments, like Jackson, Mississippi, (see section 2.2 for more information on this), its lack of system data for its Mississippi Division service lines prevented it from identifying the locations of most of the compression couplings in that system, including the accident couplings. The lacking system data affected Atmos’s risk model because system data was a primary input in the model. Although Atmos’s risk model assigned higher risk-factor weights to service lines that were missing system data (see section 1.9.3.2 for more on this), the model was incapable of determining which of the data lacking service lines posed the greatest threat to the system because of all the missing data. (See section 2.5.2 for more information on how Atmos’s lack of system data impacted its risk model.) As of this report, Atmos is still missing about 63% of the service-line data for its Mississippi Division. As discussed in section 1.9.3.1, Atmos also has significant shortfalls in service-line data at several other divisions, including its Kentucky/Mid States Division, which is missing 73% of the service-line data in Kentucky. Atmos has acquired legacy pipeline systems from companies that may not have kept records of their pipeline assets (federal regulations did not require operators to keep installation records until the mid 1970s). However, as the current owner of property that provides hazardous materials to the public, Atmos has a responsibility to learn about its system, so it can appropriately assess and address the risk to that system and to public safety. Therefore, the NTSB concludes that Atmos’s failure to gather relevant information about its service line records prevented it from effectively assessing the risk to its assets. The two accidents in Jackson and Atmos’s reported rates of missing service line data in its other divisions indicate that Atmos needs to take a more focused approach to gain data about its system. Atmos currently gathers system data through routine operations and maintenance activities, including when an employee identifies an opportunity to correct or complete a pipeline-asset record. In addition to administrative strategies, some of which Atmos currently employs, technology-based strategies, some of which the ASCE guide describes, offer other methods of gaining system data that do not involve excavating buried pipelines. A natural gas distribution pipeline operator in Louisiana, Missouri, developed a plan that allowed it to gain additional service-line data, and Atmos could do the same. Therefore, the NTSB recommends that Atmos develop and implement a program to proactively identify and collect missing service-line information for all its 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. Risk Model As discussed in section 1.7.1.2, federal regulations required natural gas distribution pipeline operators to evaluate and rank risk in their pipeline systems, and Atmos did not effectively evaluate and rank system risk in its system. In 2023, the year before the two accidents, Atmos repaired 182 hazardous (grade 1) leaks in Jackson. Although the repaired hazardo

Addressee Acronym: PHMSA

Addressee Organization Type: G-Federal Government

Communication Date: 2026-06-04

Communication Type: Official Correspondence

Communication Contents: -From Paul J. Roberti, Administrator: PHMSA Response to Safety Recommendation P-26-2: Concur. PHMSA plans to issue an advisory bulletin (ADB) by Fall 2026 (estimated), urging pipeline operators to adopt the most appropriate risk models for use within their integrity management programs (IMP), with full consideration of probabilistic risk models. PHMSA respectfully suggests NTSB consider redirecting this recommendation to industry-led, standard-setting bodies. These organizations are best positioned to develop peer-validated and scalable risk modeling methodologies that are adaptable to diverse operations without being tied to a single proprietary tool. This approach would allow probabilistic risk modeling to evolve as an industry best practice, fostering broader voluntary adoption across operators regardless of their starting point or resource levels. CONCLUSION PHMSA believes the planned actions described above address new NTSB Safety Recommendation P-26-2, and reiterated Safety Recommendations P-21-2 and P-25-3. We value our continued partnership with NTSB as we work to ensure the safe and reliable operation of the Nation’s pipeline transportation system and realize the President’s vision for unleashing American energy.