NTSB Safety Recommendation P-19-012

NTSB safety recommendation P-19-012.

TO THE WASHINGTON GAS LIGHT COMPANY: Install all new service regulators outside occupied structures.

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): An existing practice where feasible. 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 Company’s default practice is to follow this recommendation, unless otherwise not feasible. Your letter requested further information on the policies and procedures on which the Company relies to determine when installing new service regulators outside may not be feasible. In response, and to provide for additional clarity on feasibility, the following is contained in the Company’s Operations and Maintenance provisions: Washington Gas O&M Manual Section 5111, “Meter Location and Clearance Requirements”, Revision 6, Effective 09/11/2019, includes requirements for the relocation of inside regulators during service replacements. OM-5111 states: Locate meters and regulators in accordance with the following: ? New single-family residential installations: Outside. ? Legacy service replacements: Outside, unless: o An outside location would result in non-compliance with governing code or law. OR o There is a compelling basis to overcome the enhanced safety and improved access afforded by an outside location. Factors which may prevent outdoor locations include: ? Americans with Disabilities Act non-compliance ? Installations which result in an underground houseline ? Installations requiring guards for protection from vehicles or other external forces, where guards would violate traffic laws or interfere with the public right-of-way Additionally, the Company’s service territory in the District of Columbia, Maryland and Virginia includes areas that are designated as “historic districts” which can impose restrictions as to placement of meters and regulators. OM-5111 provides “Historic district permission may be required in addition to other required permits. Preliminary contact with an agency or jurisdiction may help address concerns of the agency or jurisdiction, and help determine if the agency or jurisdiction will allow the installation as proposed.” Washington Gas also considers the location of regulators serving large-demand facilities and meter banks in accordance with OM-5133, “Large Load Meter and Regulator Facilities”, OM-5131, “Meter Banks”; OM-5132, “Meter Bank Regulator Installation”; and OM-5315, “Distributed Meter Room Design and Installation”. For larger meter and regulator build-ups such as these, Washington Gas follows a policy where “regulators shall be installed outside unless there is no practical outside location”.

Addressee Organization Type: P-Private Industry

Communication Date: 2020-04-10

Communication Type: Official Correspondence

Communication Contents: We note that it is your practice to install new service regulators outside occupied structures where feasible. Before we close this recommendation, we ask that you provide us with information on the policies and procedures that you use to determine whether locating a new service regulator outdoors is feasible. Pending that information, Safety Recommendation P-19-12 is classified OPEN--ACCEPTABLE RESPONSE.

Addressee Organization Type: P-Private Industry

Communication Date: 2020-08-06

Communication Type: Official Correspondence

Communication Contents: We note that Washington Gas installs all new service regulators outside occupied structures, unless doing so would result in noncompliance with governing code or law, or if there is another compelling reason not to. At a July 17, 2020, meeting, your staff informed us that it is rare for new service regulators to be installed inside, and they can only be installed inside after a Washington Gas construction supervisor approves the justifications for doing so. We further note that new inside installations and relevant justifying documentation are being incorporated into your work management system. Accordingly, Safety Recommendation P-19-12 is classified CLOSED--ACCEPTABLE ALTERNATE ACTION.