NTSB Safety Recommendation P-21-006

NTSB safety recommendation P-21-006.

TO THE DALLAS FIRE-RESCUE DEPARTMENT: Revise your procedures to require gas monitoring after the occurrence of a gas-related structure fire or explosion.

Priority: CLASS II

Overall Status: Closed - Acceptable Action

Issued Date: 2021-02-08

Adopted Date: 2021-01-12

Overall Date Closed: 2024-04-22

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: State of Texas, City of Dallas, Fire-Rescue Department

Addressee Status: Closed - Acceptable Action

Addressee Date Closed: 2024-04-22

Addressee Organization Type: L-Local Government

Communication Date: 2021-02-08

Communication Type: Official Correspondence

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 5 through -7). 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 the Dallas Fire-Rescue Department (DFR) 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 DFR nor Atmos Energy Corporation (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 DFR. Additional information regarding these recommendations can be found in the noted sections of the report. • Revise the continuing education requirements for your arson investigators to include training on building fuel gas systems. (P-21-5) (See section 2.3.1.) • Revise your procedures to require gas monitoring after the occurrence of a gas-related structure fire or explosion. (P-21-6) (See section 2.4.) • Develop and implement a formal process to alert appropriate local, state, and federal agencies of potential systemic safety issues that should be investigated further. (P-21-7) (See section 2.6.2.) 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(s) by number (Safety Recommendation(s) P 21 5 through -7). 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. Please do not submit both an electronic copy and a hard copy of the same response.

Addressee Organization Type: L-Local Government

Communication Date: 2022-05-02

Communication Type: Official Correspondence

Communication Contents: In the 15 months since we issued these recommendations, we have not received any information from you regarding your actions to implement them. When we issued these recommendations, we asked that you advise us within 90 days detailing the actions you had taken or intended to take in response. We would appreciate receiving a response from you within 90 days regarding actions that you have completed or planned to address these recommendations. Safety Recommendations P 21 5 through -7 are currently classified OPEN-- AWAIT RESPONSE.

Addressee Organization Type: L-Local Government

Communication Date: 2024-04-22

Communication Type: Official Correspondence

Communication Contents: We note that you have revised your procedures to require gas monitoring after the occurrence of a gas-related structure fire or explosion. Accordingly, Safety Recommendation P-21-6 is classified CLOSED-- ACCEPTABLE ACTION.

Addressee Organization Type: L-Local Government

Communication Date: 2024-02-12

Communication Type: Official Correspondence

Communication Contents: -From Dominique Artis, Fire Chief, City of Dallas: In response to the safety recommendations made by the National Transportation Safety Board (NTSB) Dallas Fire-Rescue (DFR) has taken the following actions: P-21-5 DFR's continuing education requirements for fire investigators have been revised to include training on building fuel gas systems. P-21-6 DFR's procedures have been revised to require gas monitoring while on the scene of a gas-related structure fire or explosion. P-21-7 DFR's procedures require that the gas company is notified and that DFR remains on scene until a gas company representative arrives at all gas-related incidents suspected to have occurred because of a system issue. DFR has instituted a weekly automated report of all gas-related emergency calls with DFR responses that can be sent to the gas company. Finally, DFR is advancing a more robust notification system that will include appropriate local, state, and federal agencies. DFR has asked these partners to identify points of contact for notification. Attached are DFR's procedures for response to explosions, natural gas leaks, and carbon monoxide incidents, Mandatory CE requirements for arson investigators, and a letter outlining the changes DFR has implemented. Let me know if you have any questions.