NTSB Safety Recommendation P-19-013

NTSB safety recommendation P-19-013.

TO THE WASHINGTON GAS LIGHT COMPANY: Relocate existing interior service regulators outside occupied structures whenever the gas service line, meter, or regulator is replaced. In addition, multifamily structures should be prioritized over single-family dwellings.

Priority: CLASS II

Overall Status: Closed - Acceptable Alternate Action

Issued Date: 2019-06-10

Overall Date Closed: 2020-08-06

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: Washington Gas

Addressee Status: Closed - Acceptable Alternate Action

Addressee Date Closed: 2020-08-06

Addressee Organization Type: P-Private Industry

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 recommendations 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 recommendations to the Washington Gas Light Company. Additional information regarding these recommendations can be found in the noted sections of the report. • Throughout the Washington Gas network, implement an audit program to verify the data on the service forms used to determine the location and condition of mercury service regulators to ensure the accuracy of this safety-critical data. (P 19 009) (See section 2.3.9.) • Revise your procedures and field forms to require technicians to verify the integrity of vent lines following the testing of indoor service regulators throughout the Washington Gas network. (P-19-010) (See section 2.3.5.) • Establish a time frame with specific dates and milestones for the replacement of mercury service regulators throughout the Washington Gas network that recognizes the need to expedite this program and that prioritizes multifamily dwellings where mercury service regulators are located inside the property. (P-19-011) (See section 2.3.10) • Install all new service regulators outside occupied structures. (P-19-012) (See section 2.3.10.) • Relocate existing interior service regulators outside occupied structures whenever the gas service line, meter, or regulator is replaced. In addition, multifamily structures should be prioritized over single-family dwellings. (P-19-013) (See section 2.3.10.) 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, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendations by number (for example, P-19-009). 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 Organization Type: P-Private Industry

Communication Date: 2019-09-09

Communication Type: Official Correspondence

Communication Contents: -From Adrian Chapman, President and Chief Executive Officer, WGL (Washington Gas Light): It is already our practice to move service regulators outside occupied structures, when feasible, whenever gas service lines are replaced. We cannot commit to moving service regulators outside whenever a meter or regulator is replaced. For additional detail, please see the attached submissions to the District of Columbia, Maryland and Virginia public utility commissions. Consistent with Washington Gas's commitment to operating a safe and reliable system, we propose to undertake the above actions as enhancements to the safety of our system and consistent with our regulatory obligation as a safe and prudent operator. Nothing in this letter or in the proposed actions to be taken should be misunderstood as agreement with the NTSB's determination of probable cause in this matter.

Addressee Organization Type: P-Private Industry

Communication Date: 2020-05-29

Communication Type: Official Correspondence

Communication Contents: -From Donald “Blue” Jenkins, President, Washington Gas: The NTSB has recognized that it is already the Company’s practice to move service regulators outside occupied structures, when feasible, whenever gas service lines are replaced. Furthermore, as Washington Gas noted in the update to P-19-11, the Company has proposed prioritization of replacement of mercury regulators serving multi-family services (most of which are inside premises) over non-multi-family locations. In response to the NTSB’s remaining request to share with the NTSB the Company’s determination that safety considerations do not support the movement of all inside meters or regulators to the outside “whenever” the meter or regulator is replaced, Washington Gas states as follows: 1. In conformance with federal and state requirements, Washington Gas operates a safe system which includes the safe operation and maintenance of meters and regulators, including its inside installations. 2. Safe operation is maintained on a continual basis by practices such as odorizing the customer’s gas, responding to every odor call, and inspecting for leaks or other abnormal operating conditions on every service call. 3. Additionally, Washington Gas further protects against potential damage to its facilities, including those installed inside, through RP 1162 communications with customers that educates customers on unsafe inside storage practices in and around its meters and regulators, on the actions to take if a natural gas odor is smelled, and on the availability of Washington Gas qualified technicians around the clock to respond to any customer safety concern. Furthermore, the inside installation location affords certain safety protections not always obtained with outside installations, to include protection from corrosive weather elements, as well as other outside forces, such as vehicles and falling ice, known to have caused damages which can cause serious natural gas fed fires and incidents. 4. Because the inside locations do not provide complete protection from damage to WG facilities, WG included legacy inside meter and regulator installations in its safety initiative of installing fire valves on all new and replaced meter and regulation facilities. In the event of a fire impacting the meter or regulator, the elevated temperature trips the TSV, closing off further flow of gas into the structure. In that scenario, the TSV reduces the risk of natural gas further fueling the fire, complicating fire suppression activities and slowing or preventing the prompt evacuation of residents. 5. Washington Gas expects that there will be some intersection between its accelerated replacement programs, in all three of its jurisdictions, and the population of inside meter and regulator locations. For that population, the inside meter and regulator will be relocated to the outside upon the service replacement, with only minimal disruption of service to the customer. 6. Even with the safety practices outlined above, Washington Gas concurs that locating its jurisdictional piping, meters and regulators to outside locations represents an enhanced safety measure, and that practice is currently the Company’s default approach to installation of new and replaced services, as outlined above. Furthermore, Washington Gas is aware of the NTSB recommendation to the Pipeline Hazardous Materials and Safety Administration, P-19-02, and PHMSA’s response to the recommendation. WG concurs with the analysis provided by PHMSA and, in addition to complying with any new requirements that may be forthcoming, will engage constructively with the Agency, and the Company’s state regulatory authorities, as well as industry stakeholders on advisory bulletins or guidance regarding the continued safe maintenance and operation of the inside meter and regulator facilities. Washington Gas appreciates the opportunity to update the NTSB as to the Company’s continuing response to implement Safety Recommendations P19-9 through 13. Please contact me should you or your staff have questions about the foregoing report.

Addressee Organization Type: P-Private Industry

Communication Date: 2020-04-10

Communication Type: Official Correspondence

Communication Contents: We note that it is already your practice to move service regulators outside occupied structures, when feasible, whenever gas service lines are replaced; however, you cannot commit to moving service regulators outside whenever a meter or regulator is replaced. Because we specifically included meter and regulator replacements in Safety Recommendation P-19-13, it is classified OPEN--UNACCEPTABLE RESPONSE. We believe that relocating indoor regulators outside would provide a significant safety benefit, but we also recognize there may be considerable consequences associated with such a move. We invite you to share with us the criteria and process that you use to determine if the consequences of relocating an interior regulator outside outweigh the increased safety, and we will determine if these criteria and process represent an acceptable alternate response to this recommendation.

Addressee Organization Type: P-Private Industry

Communication Date: 2020-08-06

Communication Type: Official Correspondence

Communication Contents: In our April 10, 2020, letter, we noted that it is your practice to move service regulators outside occupied structures, when feasible, whenever gas service lines are replaced; however, you could not commit to moving service regulators outside whenever a meter or regulator is replaced. Because our recommendation specifically includes meters and regulators, we classified Safety Recommendation P-19-13, “Open—Unacceptable Response.” However, we recognized there may be considerable consequences associated with such a move, and asked what criteria and process you use to determine if the consequences of relocating an interior regulator outside outweigh the increased safety. We note that your inside installations conform with federal and state requirements, and that installation safety is maintained by practices such as odorization and round-the-clock response to any customer safety concern. Beyond that, you have added thermal safety valves to your legacy inside meters and regulators. We further note that you expect that your MRRP will increase the relocation of inside installations in all three of your public service commission jurisdictions. Lastly, we note that you are aware of Safety Recommendation P-19-2, which we issued to the Pipeline and Hazardous Materials Administration (PHMSA), and you concur with PHMSA’s analysis. We understand that Washington Gas is committed to complying with any new requirements PHMSA may enact regarding inside meter and regulator relocation, maintenance, and operation. We are pleased that you relocate existing interior service regulators outside occupied structures whenever the gas service line is replaced, and that you are committed to prioritizing multifamily structures. Although you cannot commit to relocating an inside installation whenever a regulator or meter is replaced, we believe that your alternate actions satisfy the intent of our recommendation. Accordingly, Safety Recommendation P-19-13 is classified, CLOSED--ACCEPTABLE ALTERNATE ACTION.