NTSB Safety Recommendation P-21-008

NTSB safety recommendation P-21-008.

TO ATMOS ENERGY CORPORATION: Provide initial and recurrent training to Dallas Fire-Rescue Department arson investigators and firefighters on the local natural gas distribution system and associated hazards.

Priority: CLASS II

Overall Status: Closed - Acceptable Action

Issued Date: 2021-02-08

Adopted Date: 2021-01-12

Overall Date Closed: 2022-05-11

Synopsis: On February 23, 2018, at 6:38 a.m. local time, a natural gas–fueled explosion occurred at 3534 Espanola Drive, Dallas, Texas. The residence sustained major structural damage, but when first responders arrived on scene at 6:44 a.m., they observed no smoke or fire. Four family members were injured, and one was killed in the explosion. Following the explosion, National Transportation Safety Board (NTSB) investigators located a through-wall crack in the 71 year old natural gas main that served the residence. In the 2 days before this explosion, two gas-related incidents occurred on the same block at houses that were served by the same natural gas main, each resulting in significant structural damage and burn injuries to one occupant. The first occurred on February 21, 2018, at 5:49 a.m., and resulted in one injury involving second-degree burns and significant structural damage to 3527 Durango Drive. The second incident occurred on February 22, 2018, at 10:21 a.m., and resulted in one injury involving second-degree burns and significant structural damage to 3515 Durango Drive. As a result of this investigation, the NTSB issued new safety recommendations to the Pipeline and Hazardous Materials Safety Administration, the Railroad Commission of Texas, the Dallas Fire-Rescue Department, Atmos Energy Corporation, and the Gas Piping Technology Committee. The NTSB is also reiterating safety recommendations to the International Code Council, the National Fire Protection Association, and the Gas Technology Institute

Probable Cause: The National Transportation Safety Board determines that the probable cause of the explosion at 3534 Espanola Drive was the ignition of an accumulation of natural gas that leaked from the gas main that was damaged during a sewer replacement project 23 years earlier and was undetected by Atmos Energy Corporation’s investigation of two related natural gas incidents on the 2 days prior to the explosion. Contributing to the explosion was Atmos Energy Corporation’s insufficient wet weather leak investigation procedures. Contributing to the severity of the explosion was Atmos Energy Corporation’s inaction to isolate the affected main and evacuate the houses. Contributing to the degradation of the pipeline system was Atmos Energy Corporation’s inadequate integrity management program.

Ntsbnumber: PLD18FR002

Report Number: PAR-21-01

Addressee Name: ATMOS Energy Corporation

Addressee Status: Closed - Acceptable Action

Addressee Date Closed: 2022-05-11

Addressee Organization Type: P-Private Industry

Communication Date: 2021-02-08

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 provide assistance to victims and their family members affected by major transportation disasters. The attached letter from the NTSB Chairman provides information about the NTSB’s January 12, 2021, report Atmos Energy Corporation Natural Gas-Fueled Explosion, Dallas, Texas, February 23, 2018, PAR-21/01. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 recommendation by number (for example, P 21 8 through -12). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, including attachments, 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 will be 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. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov. 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 (Atmos) 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 provides information about the National Transportation Safety Board’s (NTSB) January 12, 2021, report Atmos Energy Corporation Natural Gas-Fueled Explosion, Dallas, Texas, February 23, 2018, PAR-21/01. 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: • Incident investigation. Neither Dallas Fire-Rescue Department (DFR) nor Atmos identified the causes of the two incidents that occurred in the days immediately preceding the explosion. DFR arson investigators and Atmos technicians did not effectively investigate, communicate, or collaborate to determine the cause of either incident. Further, Atmos did not gather enough evidence to determine if gas migrated from their piping and fueled the first two incidents. • Leak investigations and repairs. Atmos dedicated significant resources to its response following the second incident, finding 13 leaks determined to present an existing or probable future hazard. However, none of its employees questioned the integrity of the system. As a result, Atmos did not take appropriate action to secure the safety of the area and its residents. This was attributed, in part, to inadequate procedures for performing leak investigations in wet weather conditions. • Methane detection. Although Atmos added odorant to its gas distribution system in a manner consistent with Pipeline and Hazardous Materials Safety Administration (PHMSA) regulations, none of the residents at any of the affected homes smelled gas. Although odorant can act as an early warning of a gas release to prevent an explosion and fire, it is known to become depleted if it travels through soil. • Incident reporting. Incident reporting requirements mandated by the PHMSA rely on the judgement of the operator to determine whether an incident resulted from a leak in their system and do not specify the level of investigation necessary to make the determination. While operators have an option to report events that may have been caused by their system, Atmos relied on an incomplete investigation to support its position not to report the first two incidents. Accordingly, the NTSB makes the following safety recommendations to Atmos. Additional information regarding these recommendations can be found in the noted sections of the report. • Provide initial and recurrent training to Dallas Fire-Rescue Department arson investigators and firefighters on the local natural gas distribution system and associated hazards. (P 21 8) (See section 2.3.1.) • Develop and implement more rigorous inside leak investigation requirements in response to fires and explosions when gas involvement cannot be excluded, including clear guidance on pressure testing and inside gas measurements and the potential need to return to the property after firefighters have departed. (P 21-9) (See section 2.3.2.1.) • Develop a clear procedure to coordinate with local emergency responders when investigating all fires and explosions that may be gas related to conclusively determine whether your system can be excluded as a potential contributor, and collecting the necessary evidence to support the conclusion of your investigations. (P 21-10) (See section 2.3.2.3.) • Revise your policies and procedures for responding to leaks, fires, explosions, and emergency calls to address the challenges caused by wet weather conditions. The revised policies and procedures should include: (1) leak investigation methods that are reliable in wet weather; (2) leak investigation procedures that assess all viable gas migration paths; (3) criteria for when to shut down or isolate gas distribution systems and pressure test main and service lines; and (4) an alternate safe response such as evacuation when reliable leak investigations are not possible due to wet weather or other circumstances. (P-21-11) (See section 2.4.) • Without delay, assess your integrity management program, paying particular attention to the areas identified in this investigation, and revise the program to appropriately consider: (1) threats that degrade a system over time, and (2) the increased risk that can result from factors that simultaneously increase the likelihood and consequence of failure. (P 21 12) (See section 2.7.) 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 recommendatio

Addressee Organization Type: P-Private Industry

Communication Date: 2026-03-26

Communication Type: Recommendation Mention

Communication Contents: From the report “Atmos Energy Corporation Natural Gas Fueled Home Explosions and Fires, Jackson, Mississippi, January 24, 2024, and January 27, 2024” published on March 26, 2026: 1.10.1.3 Dallas, Texas In February 2018, the NTSB investigated a natural gas-fueled explosion in Dallas, Texas, which resulted in 1 fatality; 4 injuries; a destroyed home; and the evacuation of 300 homes, 250 apartment units, and 600 students (NTSB 2021). The NTSB determined that the probable cause of the accident was the ignition of natural gas that leaked from a gas main that was damaged 23 years earlier and was undetected by Atmos’s investigation of the two related incidents that occurred in the 2 days before the explosion. The investigation found that while Atmos’s periodic leak survey methodology and frequency complied with the minimum state and federal requirements, it did not identify the degraded system that was found after the explosion. As a result, the NTSB issued Safety Recommendation P-21-2 to PHMSA to evaluate industry’s implementation of the gas distribution pipeline integrity management requirements and develop updated guidance for improving their effectiveness. Footnote: Safety Recommendation P-21-2 is currently classified Open—Acceptable Response. The investigation found that had the Dallas Fire-Rescue Department arson investigators been adequately trained on natural gas systems, their investigation findings may have provided more timely and accurate assistance to Atmos in locating the source of the gas leak. As a result, the NTSB issued Safety Recommendation P 21 8 to Atmos to provide initial and recurrent training to the Dallas Fire-Rescue Department arson investigators and firefighters on the local natural gas distribution system and associated hazards. In 2022, the NTSB classified Safety Recommendation P-21-8 Closed—Acceptable Action when Atmos detailed the initial and recurrent training it had provided to the Dallas Fire-Rescue Department and indicated that it would continue its outreach and training to those emergency response officials. The investigation found that Atmos did not adequately consider or mitigate against threats that were degrading its pipeline system, the likelihood of failure associated with the threats, or the potential consequences of such a failure as required by gas distribution integrity management requirements. As a result, the NTSB issued Safety Recommendation P 21 12 to Atmos to assess its distribution integrity management program, paying particular attention to the areas identified in the NTSB investigation, and revise the program to appropriately consider: (1) threats that degrade a system over time, and (2) the increased risk that can result from factors that simultaneously increase the likelihood and consequence of failure. In 2023, the NTSB classified Safety Recommendation P-21-12 Closed—Acceptable Action when Atmos reported that it had enhanced its distribution integrity management risk model in several ways, including enhancements that provided notice of areas where rain or other weather conditions could be causing soils to shrink or swell and therefore increase the potential for pipeline stress. The investigation also found that had methane detectors been installed at the accident homes, an alarm would have alerted residents to a gas release, reducing the potential for and consequences of the resulting natural gas fires and explosions. Footnote: Over the years, the NTSB has referred variously to these systems as “methane detectors;” “methane detection systems;” and, as in this report, “natural gas alarms.” As a result, the NTSB reiterated recommendations to the International Code Council, the National Fire Protection Association, and the Gas Technology Institute to develop requirements and standards for residential natural gas detection alarms (Safety Recommendation P-19-6, Safety Recommendation P 19 7, and Safety Recommendation P-19-8, respectively). Footnote: Safety Recommendation P-19-6 is currently classified Open—?Unacceptable Response. Safety Recommendation P 19 7 is currently classified Open—?Acceptable Alternate Response. In 2022, the NTSB classified Safety Recommendation P-19-8 Closed—?Acceptable Action when the Gas Technology Institute issued a new standard for fuel gas detection and warning equipment.

Addressee Organization Type: P-Private Industry

Communication Date: 2021-05-07

Communication Type: Official Correspondence

Communication Contents: Kevin Akers, President and CEO: Atmos Energy submits this letter and attachments in response to the National Transportation Safety Board (NTSB)’s letter dated February 8, 2021 concerning the NTSB’s January 12, 2021 Report on the incident that occurred in Dallas, Texas on February 23, 2018. As the attached responses reflect, we have either already, or soon will be, implementing the NTSB Recommendations P-21-8 through P-21-12. Our focus on safety has continued throughout this investigation, including voluntary initiatives to reduce the risk of third-party damage to our pipelines. In addition to the enhancements reflected in the Safety Recommendations, because third party damage remains one of the greatest threats to natural gas distribution systems, we have been and will continue to be a champion for damage prevention. We are committed to continuous improvement on our journey to achieve our vision to be the safest provider of natural gas services. Atmos Energy appreciates the opportunity to respond to the NTSB and we look forward to continuing to work closely with the NTSB to further enhance the safe delivery of natural gas services. Atmos Energy appreciates the work of the NTSB in connection with its response to the incident on February 23, 2018, its investigation of the probable cause, and its efforts to enhance industry safety. As we did throughout the investigation, Atmos Energy will continue to work collaboratively with the NTSB in response to the Recommendations. Atmos Energy’s commitment to safety is a core value. Our holistic approach to managing safety includes and involves observing, evaluating, and adapting to changing and challenging conditions. We are committed to continuous improvement as we work to achieve our vision of being the safest provider of natural gas service. It is in that spirit that we voluntarily implemented the safety initiatives outlined in the Supplement to Atmos Energy Corporation’s Proposed Findings, Probable Cause, and Recommendations to the National Transportation Safety Board dated September 4, 2020, including efforts to assess and strengthen our relationship with Dallas-Fire Rescue (“DFR”), especially as it relates to on-site interaction, communication, and training. Atmos has provided training to DFR for many years, including at Atmos’ Charles K. Vaughan training facility in Plano, Texas. This training helps DFR personnel understand Atmos’ gas distribution system, enhances coordination during emergency response situations, and develops and sustains relationships and communication networks at various levels in both organizations. On February 8, 2021, members of DFR leadership, including Lauren Johnson (Deputy Chief – Safety), Eric Beal (Deputy Chief – Fire Investigations), and Scott Pacot (Battalion Chief) provided a presentation to the Dallas Public Safety Committee concerning DFR’s response to the NTSB’s Final Report. The presentation (the “DFR Presentation”) included both a slide deck and a February 5, 2021 Memo from Jon Fortune, Assistant City Manager, to the Honorable Members of the Public Safety Committee titled “Dallas Fire-Rescue Response to NTSB Report on Atmos Incident” (the “DFR Memo”). The DFR Memo contained the following statement: “While DFR and Atmos Energy Corporation (Atmos) have long enjoyed a cooperative and collaborative relationship, since these incidents [in February 2018], communications have increased dramatically. Atmos has provided training sessions, allowing DFR to learn at their facilities and from their personnel about gas-related emergencies.” During the DFR Presentation, a Dallas Councilmember also commented that they had previously toured Atmos Energy’s training facility and found it to be “extraordinary,” “remarkable,” and “eye-opening.” In response to Recommendation P-21-8, Atmos has assembled a cross-functional team to evaluate ways in which to enhance its delivery of training to DFR. This team has met with members of DFR to discuss various aspects of the Atmos-DFR relationship, including training opportunities (both in person and virtual), tabletop simulations, and emergency response coordination. Atmos Energy has enhanced its First Responder web portal (https://www.atmosenergy.com/safety/firstresponders) with additional resources on natural gas systems. Atmos will continue to collaborate with DFR on emergency coordination and responses and have regular discussions with DFR leaders regarding continuous improvement and training opportunities.

Addressee Organization Type: P-Private Industry

Communication Date: 2022-01-11

Communication Type: Official Correspondence

Communication Contents: -From John McDill, Senior Vice President Utility Operations: Atmos Energy submits this letter and attachments to supplement its May 7, 2021 response to the National Transportation Safety Board (NTSB) concerning the NTSB’s January 12, 2021 Report on the incident that occurred in Dallas, Texas on February 23, 2018. As the attached supplemental responses reflect, we have completed our work relative to the NTSB Recommendations P-21-8 through P-21-12. We are committed to continuous improvement on our journey to achieve our vision to be the safest provider of natural gas services. Atmos Energy appreciates the opportunity to have participated in this investigation alongside the NTSB and other party participants to further enhance the safe delivery of natural gas services. Atmos Energy appreciates the opportunity to update the NTSB on our efforts to provide initial and recurrent training to Dallas Fire-Rescue (“DFR”) arson investigators and firefighters on local natural gas distribution systems and associated hazards relating to safety recommendation P-21-8. We remain committed to managing safety and continually improving to achieve our vision of being the safest provider of natural gas service. It is in that spirt that we have sought to improve on our already strong working relationship with DFR personnel to enhance on-site interaction, communication, and training. As mentioned in our initial May 7, 2021 response to the NTSB, Atmos and DFR have long had a cooperative and collaborative relationship, which DFR acknowledged in a public meeting with the Dallas Public Safety Committee on February 8, 2021. In that same meeting, they also referenced an increase in communication and training opportunities between our two organizations following the February 23, 2018 incident. On June 24, 2021, an NTSB Safety Recommendation Specialist requested additional details on the content, scope, and frequency of our training provided to DFR personnel. Atmos’ training for first responders is well-developed and scalable, and our instructors are experienced in delivering this content to all DFR personnel, including arson investigators, firefighters, and Hazmat team members. We have the resources to train DFR personnel at locations of their choice, or at our Charles K. Vaughan training center, just north of Dallas, which contains a scaled-down version of a neighborhood complete with natural gas piping. We welcome the opportunity to provide regular recurring training to DFR personnel and have continued our outreach to do so. In 2018 and 2019 we sent invitations to 60 DFR stations offering to schedule in-person training but did not receive any acceptances. In response to the challenges presented by COVID, in 2020 we also made a virtual training option available through a partnership with the Smalley Foundation (https://smalleyfnd.org/about-us). The Smalley Foundation is a national non-profit that provides pipeline safety training and education to audiences ranging from schools to first responders on pipeline safety and awareness and emergency response. The Smalley Foundation sends quarterly emails and an annual mailing to agencies on their list, including DFR. A coordinator from the Smalley Foundation also reaches out periodically to DFR personnel to encourage online training opportunities. Our outreach continued in 2021, including a virtual meeting between leadership within Atmos and DFR to continue discussing training opportunities, including the option of virtual training provided by the Smalley Foundation. In June 2021, the Captain/HazMat Coordinator for DFR received training from this organization. While we believe the communication, partnership, and interactions between Atmos and DFR are already strong, we will continue our outreach, both directly and through the Smalley Foundation, to provide DFR personnel (including arson investigators and firefighters) training options on our local distribution system and associated hazards consistent with Recommendation P-21-8. We appreciate the partnership we have with Dallas Fire-Rescue and the work they do to serve the community.

Addressee Organization Type: P-Private Industry

Communication Date: 2021-08-04

Communication Type: Official Correspondence

Communication Contents: We are aware that you have provided training to DFR personnel for many years, including at Atmos’s Charles K. Vaughan training facility in Plano, Texas. However, our investigation concluded that expanding natural gas distribution system training to include arson investigators and firefighters who were not assigned to DFR’s hazardous materials response team would benefit emergency response. Additionally, we noted that arson investigators were required to complete initial training in natural gas systems, but that this training was not included as a required topic in their continuing education curriculum. We note that you assembled a cross-functional team to evaluate ways to enhance your delivery of training to DFR personnel and that your efforts to provide training opportunities for DFR personnel was highlighted by DFR leadership in a February 8, 2021, presentation to the Dallas Public Safety Committee. However, to enable us to assess whether your actions satisfy our recommendation, we request that you provide more detailed information regarding the number of training spots and frequency of the training opportunities you have and will continue to provide DFR personnel on your local natural gas distribution system. Pending the receipt of a more detailed response, Safety Recommendation P-21-8 is classified OPEN-- ACCEPTABLE RESPONSE.

Addressee Organization Type: P-Private Industry

Communication Date: 2022-05-11

Communication Type: Official Correspondence

Communication Contents: We note that since the incident, you have increased your outreach to the DFR to provide initial and recurring training opportunities—including training center, in-house, and virtual options—to DFR arson investigators and firefighters on your natural gas distribution systems and associated hazards. Accordingly, Safety Recommendation P-21-8 is classified CLOSED-- ACCEPTABLE ACTION.