NTSB Safety Recommendation P-21-004

NTSB safety recommendation P-21-004.

TO THE RAILROAD COMMISSION OF TEXAS: With assistance from the Pipeline and Hazardous Materials Safety Administration, conduct a comprehensive audit of Atmos Energy Corporation’s incident-reporting practices; policies and procedures for responding to leaks, fires, explosions, and emergency calls; and integrity management programs.

Priority: CLASS II

Overall Status: Closed - Acceptable Action

Issued Date: 2021-02-08

Adopted Date: 2021-01-12

Overall Date Closed: 2022-08-23

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, Railroad Commission

Addressee Status: Closed - Acceptable Action

Addressee Date Closed: 2022-08-23

Addressee Acronym: TX RRC

Addressee Organization Type: S-State Government

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-21-4). 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 Railroad Commission of Texas (RRC) 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 the Dallas Fire-Rescue Department (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 recommendation to the RRC. Additional information regarding this recommendation can be found in the noted section of the report. • With assistance from the Pipeline and Hazardous Materials Safety Administration, conduct a comprehensive audit of Atmos Energy Corporation’s incident-reporting practices; policies and procedures for responding to leaks, fires, explosions, and emergency calls; and integrity management programs. (P-21-4) (See section 2.7.) The NTSB is vitally interested in this recommendation because it is 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 this recommendation. When replying, please refer to the safety recommendation by number (Safety Recommendation 9 21 4). 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 Acronym: TX RRC

Addressee Organization Type: S-State Government

Communication Date: 2022-07-18

Communication Type: Official Correspondence

Communication Contents: -From Wayne Christian, Chairman, Railroad Commission of Texas: The Railroad Commission of Texas (RRC) submits this letter and attachment in response to the National Transportation Safety Board (NTSB)'s January 12, 2021 Report (PAR-21/01) on the incident that occurred in Dallas, Texas on February 23, 2018. The RRC, with assistance from the Pipeline and Hazardous Materials Safety Administration (PHMSA), conducted a comprehensive audit of Atmos Energy Corporation's (Atmos Energy) incident reporting practices; policies and procedures for responding to leaks, fires, explosions, and emergency calls; and integrity management programs. The audit was conducted per recommendation P-21-4 in the NTSB's final report on the Atmos Energy Corporation Natural Gas-Fueled Explosion in Dallas, Texas on February 23, 2018. If you have any questions, please do not hesitate to contact the Oversight and Safety Division. RAILROAD COMMISSION OF TEXAS RESPONSE TO NATIONAL TRANSPORTATION SAFETY BOARD (NTSB) SAFETY RECOMMENDATION P-21-4 RELATING TO Atmos Energy INCIDENT REPORT (PAR-21-01) The Railroad Commission of Texas (RRC) with assistance from the Pipeline and Hazardous Materials Safety Administration (PHMSA) conducted a comprehensive audit of Atmos Energy Corporation's (Atmos Energy) incident reporting practices; policies and procedures for responding to leaks, fires, explosions, and emergency calls; and integrity management programs. The audit was conducted per recommendation P-21-4 in the NTSB's final report on the Atmos Energy Corporation Natural Gas-Fueled Explosion in Dallas, Texas on February 23, 2018. The audit spanned over a two-month period with in-person reviews held February 28 to March 3, 2022; March 28 to April 1, 2022; and April 25 to April 29, 2022. The audit was performed at Atmos Energy's corporate office, located at 5420 LBJ Freeway, Dallas TX. The following items were reviewed: 1) Incident Reporting Practices: Atmos Energy's reporting practices were reviewed in relation to the company's reporting procedure and the requirements of applicable Federal and State rules. As noted in the NTSB's final report, the RRC amended 16 Texas Administrative Code§ 8.210(a)(l) (Rule 8.201) to require telephonic incident reporting no later than one (1) hour following confirmed discovery. Atmos Energy's procedure, as updated, was verified to include this required provision. Though NTSB findings indicated delayed response resulting from lack of official reporting, no other significant change was made to the incident reporting procedure. 2) Policies and Procedures for responding to leaks, fires, explosions, and emergency calls: Atmos Energy's policies and procedures on leaks, fires, explosions, and emergency calls were reviewed. The RRC's audit revealed that Atmos Energy made changes to leak response procedures after the incident. The changes include enhancements to leak investigation procedures; considerations for weather conditions; employee response training; considerations for "escalated actions" when performing leak investigations; liaison procedures with fire department; and "continuing actions" when a probable or existing hazardous condition is discovered. Employee training records, leak repair, and leak monitoring records were reviewed. 3) Integrity Management (IM) Program: Atmos Energy's Distribution Integrity Management Program (DIMP) was reviewed and measured in relation to the provisions of Title 49 Part 192 Subpart B of the Code of Federal Regulations (CFR) and 16 Texas Administrative Code § 8.209 (Rule 8.209). Atmos Energy made updates to the program and integrity management model after the February 23, 2018 incident. The new model incorporates pipeline degradation and age, earth movement conditions, interactive threats, latent damage, rainfall, and other considerations. Other updates in the DIMP included measures to identify, address and reduce risks. An enhancement for unreported non-leak damages was also included and reviewed. The RRC also reviewed Atmos Energy's pipeline repair and replacement program under Rule 8.209. Findings & Conclusions: Atmos Energy's procedures and program met minimum Federal and State regulatory requirements. However, based on documents reviewed and verbal responses provided, Atmos Energy was unable to clearly demonstrate the measure of effectiveness of the enhancements made to incident reporting, leak detection and leak monitoring procedures. In addition, Atmos Energy's leak monitoring procedures were not explicit on considerations for weather conditions during leak survey. Enhancements were also made to Atmos Energy's DIMP. The audit team expressed concern over the segmentation method adopted by Atmos Energy. The 31,994 miles of pipeline operated by Atmos Energy's Mid-Tex division were subdivided into approximately 300,000 segments. Each segment ranged from 0.1 to 0.4 miles (500 to 2,000 feet) in length. In adopting this method, the calculated risk for each segment was significantly reduced. However, by confining identified threats to small sections, the possible effect or consequence over a large area was neglected. Ultimately, the overall length of pipe susceptible to failure and identified for replacement, based on risk assessment, was considerably limited. The risk model 'adopted by the operator undermines the goal of the distribution integrity management program as prescribed under Federal and State rules.

Addressee Acronym: TX RRC

Addressee Organization Type: S-State Government

Communication Date: 2022-06-02

Communication Type: Official Correspondence

Communication Contents: In the 15 months since we issued this recommendation, we have not received any information from you regarding your actions to implement it. When we issued this recommendation, 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 this recommendation. Safety Recommendation P 21 4 is currently classified OPEN-- AWAIT RESPONSE.

Addressee Acronym: TX RRC

Addressee Organization Type: S-State Government

Communication Date: 2022-08-23

Communication Type: Official Correspondence

Communication Contents: We note that, over a 2-month period, the RRC, with assistance from PHMSA, conducted a comprehensive audit of Atmos Energy Corporation’s incident reporting practices; policies and procedures for responding to leaks, fires, explosions, and emergency calls; and integrity management programs. The audit found that Atmos Energy’s procedures and program met minimum federal and state regulatory requirements; however, you concluded that Atmos Energy was unable to clearly demonstrate the measure of effectiveness that its postincident enhancements made to incident reporting, leak detection, and leak monitoring procedures. In addition, you found that Atmos Energy’s leak monitoring procedures were not explicit on considerations for weather conditions during leak surveys. We further note that your audit team expressed concern over the segmentation method adopted by Atmos Energy. You reported that the 31,994 miles of pipeline operated by Atmos Energy’s Mid-Tex division were subdivided into approximately 300,000 segments, with each segment ranging from 0.1 to 0.4 miles (500 to 2,000 feet) in length. You found that, by adopting this method, the calculated risk for each segment was significantly reduced and that the overall length of pipe susceptible to failure and identified for replacement, based on risk assessment, was considerably limited. The RCC concluded that the risk model adopted by Atmos Energy undermines the goal of the distribution integrity management program as prescribed under federal and state rules. Thank you for conducting the recommended audit and informing us of the audit findings. These actions satisfy the intent of Safety Recommendation P-21-4, which is classified CLOSED-- ACCEPTABLE ACTION.