NTSB Safety Recommendation P-19-007

NTSB safety recommendation P-19-007.

TO THE NATIONAL FIRE PROTECTION ASSOCIATION: In coordination with the Gas Technology Institute and the International Code Council, revise the National Fuel Gas Code, National Fire Protection Association 54 to require methane detection systems for all types of residential occupancies with gas service. At a minimum, the provisions should cover the installation, maintenance, placement of the detectors, and testing requirements.

Priority: CLASS II

Overall Status: Open Acceptable Alternate Response

Issued Date: 2019-06-10

Synopsis: On August 10, 2016, at 11:51 p.m., eastern daylight time, a 14-unit apartment building, located at 8701 Arliss Street, in the unincorporated community of Silver Spring, in Montgomery County, Maryland, partially collapsed due to a natural gas-fueled explosion and fire. The explosion and fire also heavily damaged an adjacent apartment building, 8703 Arliss Street, which shared a common wall with building 8701. As a result of this accident, 7 residents died, 65 residents were transported to the hospital, and 3 firefighters were treated and released from the hospital. The damage from the accident exceeded $1 million. The following are safety issues in this accident: • the location and inspection of service regulators within a structure • the inspection of the gas meter assembly • the notification of the natural gas odor to Washington Gas Light Company • the detection of natural gas through odorants and methane

Probable Cause: The National Transportation Safety Board determines that the probable cause of the explosion in building 8701 of the Flower Branch apartment complex was the failure of an indoor mercury service regulator with an unconnected vent line that allowed natural gas into the meter room where it accumulated and ignited from an unknown ignition source. Contributing to the accident was the location of the mercury service regulators where leak detection by odor was not readily available.

Keywords: Hazmat

Ntsbnumber: DCA16FP003

Report Number: PAR-19-01

Addressee Name: National Fire Protection Association

Addressee Status: Open Acceptable Alternate Response

Addressee Acronym: NFPA

Addressee Organization Type: A-Associations

Communication Date: 2021-02-08

Communication Type: Recommendation Reiteration

Communication Contents: From the Pipeline Accident Report Atmos Energy Corporation Natural Gas-Fueled Explosion Dallas, Texas February 23, 2018: 2.5 Methane Detection Odorant is the primary safety feature that members of the public rely upon to detect a natural gas release (GAO 2018). Because these gas distribution systems are situated primarily in populated areas, the odorant can act as an early warning of a gas release to prevent an explosion and fire. However, when odorized natural gas passes through the soil from a leaking supply pipe, the soil can absorb and deplete the odorant from the gas (Tenkrat and others 2010). This phenomenon has been recognized since at least 1974 when the NTSB published a report which cited “lack of odor in the leaked gas when it reached the houses and the atmosphere” as a contributing cause (NTSB 1974). Atmos added odorant to its gas distribution system in a manner that was consistent with PHMSA regulations, and yet none of the residents smelled gas prior to the incident. This is the expected response for natural gas that migrates a sufficient distance through soil, and is consistent with observations made during integrity tests after the explosion where the odor was apparent near the crack, but not noted at other excavation locations despite high methane gas readings. Many NTSB investigations have demonstrated that gas odorant does not always provide sufficient warning of gas leaks and hazardous conditions, including: • The June 28, 1982, natural gas explosion that killed five people and injured one in a single-family home in Portales, New Mexico. The natural gas release was caused by a failed service line that had been damaged from excavation work for the local telephone company over a month before the accident occurred. Between the time of the excavation work and the explosion, no one had detected gas. The natural gas was tested and found to have met the federal requirements for odorant level. At that time there was high rainfall in the region. The NTSB concluded that the odorant compounds in the gas were absorbed in the surrounding soil where the gas leaked from the service line. Soil samples were taken and supported this conclusion (NTSB 1983). • The March 5, 2008, natural gas explosion and fire that killed one person and severely injured a child in a single-family home in Plum Borough, Pennsylvania. The NTSB determined that the gas distribution pipeline had been damaged from excavation work years prior which created corrosive conditions, causing the pipe to fail. No one smelled gas 30 minutes prior to the explosion, and the gas was thought to have migrated through the porous backfill of a new sewer line and accumulated rapidly in the house with little warning to residents. Odorant levels were tested and found to be in compliance with federal requirements (NTSB 2008). As part of the investigation of the August 10, 2016, natural gas explosion and fire of an apartment building in Silver Spring, Maryland, the NTSB analyzed 20 accidents between 1971 and 2018 where natural gas had either migrated from an outside leak or within a structure and accumulated to dangerous concentrations leading to explosions, fires, fatalities, injuries, and severe property damage (NTSB 2019). The NTSB identified within those investigations whether gas odorant played a significant role in warning the occupants about the presence of gas in buildings. In some of these 20 cases, as in the three events in Dallas in February 2018, gas odor was not detected by the occupants in time for them to evacuate before the explosion occurred, despite the odorant levels being compliant with regulatory requirements. In several of the 20 cases, the NTSB cited odorant fade due to soil adsorption as a contributing factor. Based on this analysis, the NTSB concluded that the use of gas odorants alone does not effectively mitigate the risk of death and injuries caused by gas system leaks (NTSB 2019). The residents at 3534 Espanola Drive did not smell gas and were not alerted by DFR or Atmos officials of the potential hazard at any point before the explosion occurred. Likewise, none of the residents at either of the first two incident houses smelled gas prior to the incidents. Finally, had there been an alarm to warn of a natural gas release, residents could have been notified earlier to evacuate to a safe place away from the residence, without relying on someone within the house to smell gas odors or an outside party to notify them of the hazard. The NTSB concludes that had methane detectors been installed at the residences located on Durango and Espanola Drives, an alarm would have alerted residents to a gas release, reducing the potential for and consequences of the resulting natural gas fires and explosions. For 45 years, the NTSB has recommended that methane detectors be required to provide early warning of gas leaks. As a result of its investigation of an April 22, 1974, natural gas explosion in a commercial building in New York City, New York, on April 19, 1976, the NTSB issued Safety Recommendation P-76-12 to the US Department of Housing and Urban Development (HUD) (NTSB 1976). The investigation report noted that many commercial buildings were required to have smoke or heat detectors placed in strategic interior locations; therefore, it seemed logical for similar requirements to be adopted for installing gas detectors. Investigate the practicality and the availability of gas vapor detection instruments for installation at strategic locations in buildings. Based on the results of this investigation, recommend guidelines to appropriate State and local government agencies for regulations for the installation of gas detection instruments in buildings. (P-76-12) HUD responded that gas detectors were technically possible, but the agency did not believe they were practical at the time. HUD also said that it would continue to review developments in the field and would reevaluate its position “when a practical, cost effective natural gas detection system is developed.” The NTSB made a similar recommendation as a result of the investigation of a June 9, 1994, natural gas explosion and fire in a retirement home in Allentown, Pennsylvania (NTSB 1996). The NTSB’s investigation found that the performance and cost-effectiveness of gas detectors had improved in the 20 years since Safety Recommendation P-76-12 was issued. Therefore, the NTSB issued Safety Recommendation P-96-16 to HUD: Evaluate the safety benefits of using gas detectors in buildings approved by the Department for Federal rent subsidies as a means of providing building occupants and local emergency-response agencies with early notice of released natural gas within buildings; require that gas detectors be used in buildings in which the Department has determined that a gas detector would be cost effective and beneficial. (P-96-16) For 5 years, HUD did not respond to this safety recommendation. In July 2001, HUD declined to implement the recommendation because it claimed that it did not have the statutory authority and that gas detection should be required in the National Fire Code. The NTSB classified this safety recommendation Closed?Unacceptable Action. Currently, methane gas or combustible gas alarms are not required by federal or state regulations, nor are they required in building or fire codes for residential occupancies. While smoke and carbon monoxide alarm requirements have been incorporated into many state regulations, methane detection alarms have not been widely adopted. In the United States, the NFPA and the International Code Council (ICC) are nationally recognized standard-setting bodies for both building and fire codes, as well as fuel gas codes such as the International Fuel Gas Code (IFGC) and the National Fuel Gas Code (NFPA 54). The IFGC and NFPA 54 provide minimum safety requirements for the design and installation of fuel gas piping systems in homes and

Addressee Acronym: NFPA

Addressee Organization Type: A-Associations

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 Acronym: NFPA

Addressee Organization Type: A-Associations

Communication Date: 2025-04-08

Communication Type: Recommendation Mention

Communication Contents: From the Pipeline Investigation Report PIR-25-01, “UGI Corporation Natural Gas-Fueled Explosion and Fire, West Reading, Pennsylvania, March 24, 2023” published on April 8, 2025: 2.5.1 Natural Gas Alarms Public awareness is an effective tool to encourage adoption of safety devices like natural gas alarms. The first edition of API RP 1162 requires that public awareness programs include safety messages about the awareness of hazards and prevention measures as well as leak recognition and response but does not specifically require these programs to disseminate safety messages about natural gas alarms. UGI’s public awareness materials distributed before the accident were consistent with federal regulations, and although the materials promoted the use of smoke and carbon monoxide alarms, they did not address natural gas alarms. Following the accident, UGI now includes safety messages encouraging the purchase of natural gas alarms in its public awareness materials. The NTSB concludes that installing natural gas alarms can alert people of a gas leak so they can evacuate the area; however, natural gas customers may not be aware of the necessity of such alarms. The NTSB believes that messages about the benefits of natural gas alarms are critically important and could save lives when natural gas alarms are installed. The NTSB further believes that the natural gas industry can help shape the effectiveness of public awareness program delivery methods so that people in businesses, schools, residences, and other places of congregation are better informed, both about natural gas hazards and the necessity of natural gas alarms. The American Gas Association, which represents natural gas pipeline operators throughout the US, can facilitate industry efforts to improve public awareness program delivery methods and to improve safety, most critically through increasing the installation of natural gas alarms. Therefore, the NTSB recommends that the American Gas Association share the details of the March 24, 2023, natural gas–fueled explosion and fire in West Reading, Pennsylvania, with its members, encouraging them to evaluate the effectiveness of their current delivery methods of public awareness programs and to promote the installation of natural gas alarms in businesses, residences, and other places of congregation that they serve. Evacuation should occur immediately upon detection of the presence of natural gas. In 1976, the NTSB made its first recommendation to require natural gas detection to provide early warning of leaks. Footnote: As a result of its investigation of an April 22, 1974, natural gas explosion in a commercial building in New York City, the NTSB recommended that the US Department of Housing and Urban Development advance guidelines for the installation of gas detection instruments in buildings. The recommendation was classified Closed—Acceptable Action in 1985 based on the lack of practical and affordable technology at the time. Most recently, after a 2016 building explosion in Silver Spring, Maryland, and then again after the 2018 home explosion in Dallas, we made recommendations to the ICC and the NFPA to require natural gas alarms with methane detection in residences (NTSB 2019). 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. We recommended the ICC work with the Gas Technology Institute and NFPA to Incorporate provisions in the International Fuel Gas Code that requires methane detection systems for all types of residential occupancies with gas service. At a minimum, the provisions should cover the installation, maintenance, placement of the detectors, and testing requirements. (P 19 6) Footnote: NTSB Safety Recommendation P-19-6 is classified Open—Unacceptable Response based on pending adoption of provisions requiring methane detection systems in residences into the IFGC. We made a similar recommendation to the NFPA: In coordination with the Gas Technology Institute and the International Code Council, revise the National Fuel Gas Code, National Fire Protection Association 54 to require methane detection systems for all types of residential occupancies with gas service. At a minimum, the provisions should cover the installation, maintenance, placement of the detectors, and testing requirements. (P-19-7) Footnote: NTSB Safety Recommendation P-19-7 is classified Open—Acceptable Alternate Response based on the pending incorporation of NFPA 715 into NFPA 54 or other appropriate code. Continuous monitoring systems such as a natural gas alarm can provide early warning of a gas leak and can warn people to evacuate well before natural gas ignites. Footnote: Although it was not the case in this accident, odorant can be stripped from natural gas in certain situations. The NTSB investigation of the Dallas explosion found that the soil had absorbed and depleted the natural gas odorant, eliminating the opportunity for occupants to detect it. An alarm offers a clear signal that there is an unsafe or emergency condition and, particularly in a workplace environment in which fire drills are a familiar practice, tells employees what they must do—evacuate. In the case of this accident, an alarm would have made it clear to Palmer employees that an emergency existed. Palmer’s evacuation procedures at the time of the accident directed employees to leave the building when a fire alarm sounded. Considering the absence of natural gas emergency procedures at Palmer, had the company installed natural gas alarms before the accident, the sound of the alarm would have warned Palmer employees to evacuate before the explosion. Further, for those who were worried that evacuating would compromise their employment, an alarm would give them the reassurance they were doing the right thing. Therefore, the NTSB concludes that had natural gas alarms been installed inside Buildings 1 and 2, an alarm could have alerted employees to the natural gas leak, likely prompting them to evacuate, reducing or eliminating the fatal consequences of the explosion. Following the accident, Palmer did install natural gas alarms. Recognizing the safety benefits of natural gas alarms in building evacuation and emergency response, some pipeline operators have begun to install natural gas alarms in buildings with natural gas service (Leon 2022). In 2020, the ICC reported that the NFPA was developing NFPA 715, “Standard for the Installation of Fuel Gases Detection and Warning Equipment.” The standard was issued in 2022 and covers the “selection, design, application, installation, location, performance, inspection, testing, and maintenance of fuel gas detection and warning equipment in buildings and structures” (NFPA 2023). Like all standards, NFPA 715 offers detailed technical criteria that can be used to meet a code, however, it has not yet been incorporated into NFPA 54. The NTSB believes that NFPA 715 is a comprehensive standard that could be incorporated by reference into the fuel gas codes. Therefore, the NTSB recommends that the ICC revise the IFGC to provide for required installation of natural gas alarms that meet the specifications of NFPA 715 for buildings that use natural gas. The NTSB likewise recommends that the NFPA revise NFPA 54 (the National Fuel Gas Code) to provide for required installation of natural gas alarms that meet the specifications of NFPA 715 for buildings that use natural gas. Although some states incorporate NFPA and ICC codes into their laws by reference, states vary in which codes they adopt, enforcement mechanisms, and general laws pertaining to the use of natural gas and natural gas alarms in buildings where people congregate. Footnote: Buildings where people congregate include schools, workplaces, and recreational facilities. The NTSB concludes that because adoption of codes and other rules related to

Addressee Acronym: NFPA

Addressee Organization Type: A-Associations

Communication Date: 2024-11-20

Communication Type: Recommendation Mention

Communication Contents: This information is preliminary and subject to change. From the Preliminary Report PLD25FR001, “Enbridge Inc. Natural Gas-Fueled Home Explosion, South Jordan, Utah, November 6, 2024,” published on November 20, 2024: On November 6, 2024, about 3:09 p.m., a natural gas-fueled explosion fatally injured one person and destroyed a home in South Jordan, Utah. Footnote: All times in this report are local times. There were no other injuries reported. Several nearby residences were damaged, and families were displaced. (See figure.) The South Jordan Fire Department responded and arrived on scene in about 6 minutes. Enbridge Inc. (Enbridge) subsidiary, Enbridge Gas Utah, provided natural gas service to the home. Footnote: In June 2024, Canada-based Enbridge purchased local gas distribution company Questar Gas from Dominion Energy, Inc. and renamed it Enbridge Gas Utah, Enbridge Gas Wyoming, and Enbridge Gas Idaho. Enbridge responded and arrived on scene about 3:45 p.m. and worked continuously to find and isolate the leak; Enbridge isolated the leak about 12:16 p.m. on November 7. At the time of the explosion, conditions were daylight and clear; the temperature was 41°F with no precipitation. After the accident, Enbridge found a leak about 150 feet northeast of the home on a 4-inch diameter Aldyl A natural gas main it owned and operated. Footnote: Aldyl A is the trademarked name of a polyethylene plastic gas pipeline product that was manufactured by the DuPont chemical company using a proprietary polymer resin. It is no longer manufactured or used in new pipelines. The Aldyl A main was manufactured and installed in 1976 and operated at a pressure of about 45 psig, below the legal maximum allowable operating pressure of 60 psig. Enbridge detected subsurface gas between the main and two neighboring residences, including the accident home and the home immediately to the north. The subsurface gas extended from the main to the backyard and front yard of each home, reaching about 250 feet from the leak. Enbridge also detected gas in the atmosphere of the neighboring home after the accident. Before National Transportation Safety Board (NTSB) investigators arrived, Enbridge conducted pressure testing; completed leak surveys; and removed, retained, and repaired the failed main. After NTSB investigators arrived, Enbridge continued testing for gas in the area surrounding the exploded home. While on scene, NTSB investigators examined the site where the explosion occurred, reviewed Enbridge’s operational procedures, gathered documentation, conducted interviews, and recovered physical evidence for examination by the NTSB Materials Laboratory. Preliminary information indicates that none of the five residents reported smelling gas before the explosion and there was not a natural gas alarm in the accident home. Footnote: Natural gas alarms, or methane detectors, are not required in residential structures but are recommended by the NTSB. See: data.ntsb.gov/carol-main-public/sr-details/P-19-006, data.ntsb.gov/carol-main-public/sr-details/P-19-007, and data.ntsb.gov/carol-main-public/sr-details/P 19-008. The NTSB’s investigation is ongoing. Future investigative activity will focus on Enbridge’s integrity management program, emergency response procedures, public awareness program, and pipeline safety management system, as well as other causal factors. Parties to this NTSB investigation include the Pipeline and Hazardous Materials Safety Administration; the Utah Department of Public Safety, Office of the State Fire Marshal; the Utah Department of Commerce, Division of Public Utilities, Pipeline Safety Section; the City of South Jordan; and Enbridge.

Addressee Acronym: NFPA

Addressee Organization Type: A-Associations

Communication Date: 2023-07-06

Communication Type: NPRM Response

Communication Contents: The National Transportation Safety Board (NTSB) has reviewed the Pipeline and Hazardous Materials Safety Administration’s (PHMSA’s) notice of proposed rulemaking (NPRM) titled, “Pipeline Safety: Gas Pipeline Leak Detection and Repair,” published at 88 Federal Register 31890 on May 18, 2023. The NPRM proposes to amend portions of Title 49 Code of Federal Regulations (CFR) Parts 191, 192, and 193 to implement congressional mandates in the Protecting our Infrastructure of Pipelines and Enhancing Safety Act of 2020 to reduce methane emissions from new and existing gas transmission pipelines, gas distribution pipelines, regulated gas gathering pipelines, underground natural gas storage facilities, and liquefied natural gas facilities. In its NPRM, PHMSA documented a detailed evaluation of several of its regulations and proposed amendments to: • strengthen leakage survey and patrolling requirements; • establish performance standards for advanced leak detection programs; • clarify leakage survey, investigation, and repair personnel qualification requirements; and • codify congressional mandates in federal regulation. Some of PHMSA’s proposed amendments, if implemented, will help improve pipeline leak detection and mitigation, an item on the NTSB’s Most Wanted List for 2021–2023. Footnote: https://www.ntsb.gov/Advocacy/mwl/Pages/default.aspx The NTSB first identified the need for leak detection and mitigation methods about 50 years ago and is encouraged by proposals in the NPRM that may enhance the industry’s performance in detecting and safely responding to pipeline leaks. We offer comments in the following topic areas: leakage survey requirements and advanced leak detection programs, in-home methane detectors, leak-prone materials, and leak detection systems. In-Home Methane Detectors Although pipeline operators may discover or be alerted to leaks through various activities, such as maintenance or odor complaints, these strategies will not consistently locate all hazardous leaks. When natural gas migrates through the soil into a home, the odorant may be stripped from the gas, and the resident would not be aware of the need to evacuate and alert the pipeline operator. Footnote: Because natural gas is odorless, strong-smelling chemical additives called odorants are mixed with natural gas before distribution to help reduce the risk that leaks will go unidentified. In-home methane detectors are one method of continuous monitoring that can help pipeline operators identify leaks and improve safety performance. In August 2016, the NTSB investigated a building explosion and fire that partially collapsed a 14-unit apartment building in Silver Spring, Maryland. Footnote: For more information, see Building Explosion and Fire, Silver Spring, Maryland, August 10, 2016. NTSB/PAR-19/01. Washington, DC: NTSB. As a result of the accident, 7 residents died, and 68 others were injured. The explosion was caused by the failure of an indoor mercury service regulator with an unconnected vent line that allowed natural gas to leak into and accumulate in the basement. Footnote: The vent line was a pipe designed to direct natural gas outside of the building if the system was overpressurized. In home methane detectors could have helped mitigate the consequences of the Silver Spring accident by alerting residents to the leak and giving them time to evacuate and call 9-1-1. As a result of the investigation, we made the following safety recommendations to the International Code Council and to the National Fire Protection Association (NFPA), respectively: In coordination with the Gas Technology Institute and the National Fire Protection Association, incorporate provisions in the International Fuel Gas Code that requires methane detection systems for all types of residential occupancies with gas service. At a minimum, the provisions should cover the installation, maintenance, placement of the detectors, and testing requirements. (P-19-6) Footnote: Safety Recommendation P-19-6 is currently classified Open—Acceptable Response based on the development of NFPA 715, “Standard for the Installation of Fuel Gases Detection and Warning Equipment,” for reference in the International Fuel Gas Code. In coordination with the Gas Technology Institute and the International Code Council, revise the National Fuel Gas Code, National Fire Protection Association 54 to require methane detection systems for all types of residential occupancies with gas service. At a minimum, the provisions should cover the installation, maintenance, placement of the detectors, and testing requirements. (P-19-7) Footnote: Safety Recommendation P-19-7 is currently classified Open—Acceptable Alternate Response based on the pending incorporation of NFPA 715 into NFPA 54 or other appropriate code. The NTSB reiterated these recommendations as a result of our investigation of the Dallas, Texas, accident. Had methane detectors been installed at the three Dallas homes affected by the natural gas main leak, occupants could have been alerted to the leak and had time to evacuate. In the NPRM, PHMSA states that it encourages the adoption of in-home methane detectors and invites comments on the value of requiring these and other continuous monitoring systems. Although pipeline operators were not the recipients of recommendations P-19-6 and P-19-7, both the Silver Spring and Dallas NTSB investigations demonstrated the potential safety value of continuously monitoring the atmosphere by using in-home methane detectors. Recognizing that such devices can provide early warning of jurisdictional gas leaks, some pipeline operators are installing them in buildings that receive natural gas service. Footnote: “In-Home Methane Leak Detection: A Case Study” (paper presented at the Pipeline Safety Trust Conference, December 2022). For more information, see https://pstrust.org/2022-conference, accessed June 6, 2023. The NTSB urges PHMSA to consider in its final rule how in-home methane detector technology may be incorporated into pipeline operators’ leak management programs.

Addressee Acronym: NFPA

Addressee Organization Type: A-Associations

Communication Date: 2019-06-10

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 your organization 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 NTSB and our recommendation process, please see the attached one-page summary. On April 24, 2019, the NTSB adopted its report, Building Explosion and Fire, Silver Spring, Maryland, August 10, 2016, NTSB/PAR-19/01. 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, the NTSB identified the following safety issues: • The location and inspection of service regulators within a structure. • The inspection of the gas meter assembly. • The notification of the natural gas odor to Washington Gas Light Company. • The detection of natural gas through odorants and methane. Accordingly, the NTSB makes the following safety recommendation to the National Fire Protection Association. Additional information regarding this recommendation can be found in the noted section of the report. • In coordination with the Gas Technology Institute and the International Code Council, revise the National Fuel Gas Code, National Fire Protection Association 54 to require methane detection systems for all types of residential occupancies with gas service. At a minimum, the provisions should cover the installation, maintenance, placement of the detectors, and testing requirements. (P-19-007) (See section 2.5.2.) 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, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-007). We encourage you to submit your response to correspondence@ntsb.gov. If your reply exceeds 20MB, 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.

Addressee Acronym: NFPA

Addressee Organization Type: A-Associations

Communication Date: 2019-08-27

Communication Type: Official Correspondence

Communication Contents: -From L. Seth Statler, Director of Government Affairs: The first action we took was the distribution of the adopted report, NTSBIPAR-19-01, to the National Fuel Gas Code Technical Committee, who are responsible for NFPA 54. They already were scheduled to meet as part of their Second Draft meeting on the next code revision, but staff believed it was important to provide the committee with early notification of the NTSB recommendation. The report was provided as part of the agenda for the committee's July 8, 2019 meeting. Because this was the Second Draft stage of the code development process, it was not appropriate for them to take action at this time with respect to the recommendation. However, NFPA staff will continue to update NTSB on the actions of this committee when it convenes for the next revision cycle. Three members of your staff - Julie Perrot, Rachael Gunaratnum, and Sean Lynum - joined NFPA Senior Director Guy Colonna and myself on a conference call held July 26, 2019 to discuss our proposed approach to standards development intended to address the Board recommendation. Several activities are underway to address the NTSB concerns. Even before learning of the incident and the Board's investigation, NFPA received a "new project initiation request" in August 2018 from a stakeholder active with NFPA 54. In response to incidents like Silver Spring and many others throughout the US, the request seeks action by the NFPA Standards Council to consider establishing a new technical committee to develop a new standard on residential gas detection. Specifically, the request recommends that the new standard address installation and placement of single and multi-station residential combustible gas detectors that specifically detect common fuel gases, such as natural gas (methane) and liquefied petroleum gas (LPG or propane). The NFPA Standards Council approved the request during its April 2019 meeting, and at its recent August meeting, the Council voted to approve the committee scope and membership roster for this new committee NFPA acknowledges the specific recommendation of the Board, which was to revise NFPA 54 to require residential methane gas detection with requirements addressing installation, maintenance, placement, and testing of detectors. NFPA believes that the alternative strategy to create a stand-alone standard specifically for residential gas detection devices and systems achieves and even exceeds the technical intent of your recommendation for the following reasons: (1) As outlined in the recommendation, the NFPA 54 committee does not have the requisite expertise to develop new requirements specific to gas detection. For that reason, creating the separate committee with unique expertise only related to residential gas detection assures a final set of requirements that address all aspects of gas detection, including those in the Board's recommendation. Once developed, NFPA 54 could be revised to refer to this new standard to ensure provisions for gas detection are included in the code in the future. Furthermore, based on comments during our discussion with your staff, the inclusion of a reference to this new residential gas detector standard within NFPA 54 enables widespread implementation of the new requirements due to the broad adoption of NFPA 54 throughout the US. It is also likely that this life safety requirement for residential gas detection could be incorporated into NFPA 101®, Life Safety Code®, as well as building and fire codes, further ensuring wide adoption. (2) The Board's recommendation speaks specifically to methane gas detection, while NFPA 54 addresses all fuel gases (flammable gases used for gas fuel-burning appliances), which most commonly includes both natural gas (methane) as well as liquefied petroleum gas (LPG which is generally referred to as propane). NFPA believes that a separate standard that is specific to residential gas detection devices and systems would allow a result that exceeds the Board's recommendation because it covers both common fuel gases and is not limited to methane as stated in the recommendation. A new gas detection-specific standard would be able to include requirements that recognize and address the gas behavior differences for methane and propane; for example, different lower flammable (explosive) limits (LFL or LEL) and different vapor densities (applies to whether gas rises or sinks upon release). Those two characteristics alone are essential in order to fully meet the provisions defined by the Board's recommendation. A separate standard assures that NFPA would meet or exceed the Board's request. (3) One additional reason for the approach that NFPA has proposed involves a parallel research effort proposed by the same stakeholder who requested the new standards project. The Fire Protection Research Foundation (FPRF) functions as a separate, but affiliated, research arm for NFPA to explore research and data driven answers to questions or problems that emerge from our standards development activities. The FPRF received a request to conduct a study of the placement of the residential gas detectors in order to better guide and inform the standards development process. That project is currently seeking qualified researchers to perform the proposed work. Upon completion the results have the potential to strengthen the requirements developed by the new committee, thus another instance where the proposed NFPA approach would potentially exceed the request in the recommendation. (4) Because the NFPA consensus standards development process attracts a diverse range of stakeholders, the awareness of this effort is broad and the process affords a forum for the widest representation of interests and stakeholder groups. As part of the ongoing solicitation of committee applicants, NFPA wants the Board to know that both ICC and GTI, co-recipients of the recommendation to address residential gas detection, have applied to the new NFPA technical committee and have been appointed to the committee as of the August Council meeting. We appreciate the positive feedback from your staff to this alternate approach addressing the Board's recommendation. As discussed during the call, all NFPA committee meetings are open to the public, and we encourage your staff to consider attendance at the initial meeting of this committee as it begins its work in order to brief the committee on the incident, lessons learned and the specifics of the recommendation. NFPA and its staff cannot control the process or content of any standard to be ultimately developed through our process. However, as we have demonstrated through prior interactions with your Board (high-hazard freight train derailments for example) and the Chemical Safety and Hazard Investigation Board, we believe a new technical committee formed under ANSI consensus rules will be responsive to the important safety issues NTSB has identified in the P-19-007 recommendation. Senior Director Guy Colonna intends to provide regular updates to your staff on the progress of these actions that have been initiated. At the same time, as the Director of Government Affairs for NFPA, I stand ready to provide assistance on this or any other issue. We appreciate the opportunity to work with you, other members of your Board and the NTSB staff. We commend you for the very difficult but important safety role that NTSB performs.

Addressee Acronym: NFPA

Addressee Organization Type: A-Associations

Communication Date: 2022-05-05

Communication Type: Official Correspondence

Communication Contents: -From Christian Dubay, P.E., Vice President and Chief Engineer: This correspondence is in response to NTSB Safety Recommendation P-19-007, in which the NTSB recommended that the NFPA, “in coordination with the Gas Technology Institute and the International Code Council, revise the National Fuel Gas Code, National Fire Protection Association 54 to require methane detection systems for all types of residential occupancies with gas service. At a minimum, the provisions should cover the installation, maintenance, placement of the detectors, and testing requirements.” We would like to provide an update on our efforts towards addressing this recommendation. As described in correspondence from August 2019, the NFPA Standards Council approved a new Technical Committee to develop a standard on fuel gas detectors. This new standard, NFPA 715, Standard for the Installation of Fuel Gases Detection and Warning Equipment, has been issued with an effective date of April 9, 2022. The Gas Technology Institute is represented on the Technical Committee and participated in the development of this standard. The scope of this new document is as follows: 1.1.1 This standard shall be concerned with life safety and protection of property. 1.1.2* This standard shall cover the selection, design, application, installation, location, performance, inspection, testing, and maintenance of fuel gas detection and warning equipment in buildings and structures. 1.1.3 This standard shall contain requirements for the selection, installation, operation, and maintenance of equipment that detects concentrations of fuel gases that could pose a life or property safety risk. Subsequently, the National Fuel Gas Code Technical Committee, which is responsible for NFPA 54, National Fuel Gas Code, has reviewed the NTSB Safety Recommendation P-19-007 as well as the new standard NFPA 715 and has taken two relevant actions. First, the Technical Committee has revised Annex D Suggested Emergency Procedure for Gas Leaks with First Revision 32 to include a new section D.2 as follows: D.2 Where accumulation of gas inside a building is detected by odor or by activation of a combustible gas detector or system designed and installed in accordance with NFPA 715, the procedures in Section D.1 should be followed. Section D.1 contains immediate actions to be taken in the case of a gas leak. Annex D is not a part of the requirements of the National Fuel Gas Code but is included for informational purposes only. The Technical Committee also created Committee Input 48 (CI 48) to propose adding the following section to chapter 4: 4.X Gas Detection. Where fuel gas detection and warning equipment is required in residential occupancies with gas service, the installation shall be in accordance with NFPA 715, Standard for the Installation of Fuel Gases Detection and Warning Equipment. A Committee Input is a proposed technical committee–generated revision that the technical committee does not want to put in the first draft but wants published for public review in the first draft report. To become proposed legislative text for the second draft stage, this proposal would need to have public comment suggesting revision or have second revision language proposed at the second draft meeting. If the NTSB would like this language included in Chapter 4, a Public Comment should be submitted in support. The Technical Committee has stated in their Committee Statement for CI 48 that requiring fuel gas detectors in residential or other occupancies with gas service would be better addressed in building and fire codes, such as NFPA 101, Life Safety Code® or NFPA 5000, Building Code. These codes address the installation of similar warning equipment, such as carbon monoxide alarms, and the Technical Committee believes that the enforcing authorities who enforce the Life Safety Code or the Building Code would be better equipped to enforce fuel gas detector requirements in residential and other occupancies. On a related note, the ICC Committee Action Hearings were held the week of March 27 to April 6, 2022. One of the items that was on the docket to be considered for the Residential Building Code (IRC), RB18- 22, would add a requirement for fuel gas alarms or detection, and would require household fuel gas detection systems to comply with NFPA 715. Item RB18-22 failed in the committee but can still be brought back via their public comment process. If the NTSB would like to comment on the proposed new section 4.X Gas Detection in NFPA 54, or comment on any other portion of the draft, the First Draft Report is now posted at www.nfpa.org/54next and is open for public comments until May 31, 2022. NFPA 101, Life Safety Code® or NFPA 5000, Building Code, are also open for public comments until May 31, 2022 at www.nfpa.org/101next and www.nfpa.org/5000next respectively. Since the topic was not introduced to NFPA 101 or NFPA 5000 at the First Draft stage, another option is to propose a Tentative Interim Amendment (www.nfpa.org/tia). Laura Moreno, Standards Lead, Industrial and Chemical Safety (lmoreno@nfpa.org or 617-984-7496) can assist your team with that process, should you choose to pursue Public Comments or a TIA as a next step. We look forward to continued open communication and the opportunity to work with the NTSB towards a shared safety mission.

Addressee Acronym: NFPA

Addressee Organization Type: A-Associations

Communication Date: 2019-12-16

Communication Type: Official Correspondence

Communication Contents: We note that you have distributed our investigative report, Building Explosion and Fire, Silver Spring, Maryland, August 10, 2016 (PAR-19-01), to the National Fuel Gas Code Technical Committee, who is responsible for NFPA 54, and that you will update us on the committee’s actions after it convenes for the next revision cycle. We further note that, during its April 2019 meeting, the NFPA Standards Council approved a new technical committee to develop a standard on residential gas detection that will address the installation and placement of single and multistation residential combustible gas detectors that detect methane and liquefied petroleum gas (propane). The NFPA Council subsequently approved the new technical committee’s scope and membership roster at its August 2019 meeting. We understand that you believe that, in lieu of revising the National Fuel Gas Code, National Fire Protection Association 54 as requested in in our recommendation, creating a standard specifically for residential gas detection devices and systems achieves and exceeds the technical intent of the recommendation. We agree that, once complete, these actions will satisfy Safety Recommendation P-19-7. Pending completion and implementation of a new standard to require methane detection systems for all types of residential occupancies with gas service (to cover, at a minimum, detector installation, maintenance, placement, and testing), Safety Recommendation P-19-7 is classified OPEN--ACCEPTABLE ALTERNATE RESPONSE.

Addressee Acronym: NFPA

Addressee Organization Type: A-Associations

Communication Date: 2022-07-20

Communication Type: Official Correspondence

Communication Contents: First, we commend you for developing the new standard, NFPA 715, Standard for the Installation of Fuel Gases Detection and Warning Equipment. Publishing this new standard was a significant accomplishment and satisfied the intent of our related recommendation, Safety Recommendation P-19-8, issued to the Gas Technology Institute, to develop standards for residential methane detection systems. The next step to requiring residential methane detectors is to get NFPA 715 incorporated into the code. We recommended that you revise the National Fuel Gas Code (NFPA 54) to require methane detection systems for all types of residential occupancies with gas service. We note that you have taken initial steps to reference the new standard in NFPA 54; however, we further note that your National Fuel Gas Code Technical Committee has suggested that requiring fuel gas detectors in residential or other occupancies with gas service would be better addressed in building and fire codes, such as NFPA 101, Life Safety Code, or NFPA 5000, Building Code. Our staff will reach out to schedule a meeting to discuss next steps to incorporate NFPA 715 into the appropriate codes. Pending the incorporation of the Standard for the Installation of Fuel Gases Detection and Warning Equipment into the NFPA 54, or other appropriate code, Safety Recommendation P-19-7 remains classified OPEN-- ACCEPTABLE ALTERNATE RESPONSE.