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Safety Recommendation Details

Safety Recommendation P-18-008
Details
Synopsis: On September 13, 2018, about 4:00 p.m. eastern daylight time, a series of explosions and fires occurred after high-pressure natural gas was released into a low-pressure gas distribution system in the northeast region of the Merrimack Valley, Massachusetts. The distribution system was owned and operated by Columbia Gas of Massachusetts (Columbia Gas), a subsidiary of NiSource, Inc. The system overpressure damaged 131 structures, including at least 5 homes that were destroyed in the city of Lawrence and the towns of Andover and North Andover. Most of the damage was a result of structure fires ignited by gas-fueled appliances. Several structures were destroyed by natural gas explosions. One person was killed and at least 21 individuals, including 2 firefighters, were transported to the hospital. Seven other firefighters received minor injuries.
Recommendation: TO NISOURCE: Apply management of change process to all changes to adequately identify system threats that could result in a common mode failure. (Urgent)
Original recommendation transmittal letter: PDF
Overall Status: Closed - Acceptable Action
Mode: Pipeline
Location: Merrimack Valley, MA, United States
Is Reiterated: No
Is Hazmat: No
Is NPRM: No
Accident #: PLD18MR003
Accident Reports: Preliminary Report Pipeline: Over-pressure of a Columbia Gas of Massachusetts Low-pressure Natural Gas Distribution SystemSafety Recommendation Report: Natural Gas Distribution System Project Development and Review (Urgent)Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts
Report #: PSR-18-02
Accident Date: 9/13/2018
Issue Date: 11/15/2018
Date Closed: 10/24/2019
Addressee(s) and Addressee Status: NiSource, Inc. (formerly Columbia Gas) (Closed - Acceptable Action)
Keyword(s):

Safety Recommendation History
From: NTSB
To: NiSource, Inc. (formerly Columbia Gas)
Date: 10/24/2019
Response: From NTSB Report PAR-19-02: Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018: 2.2 NTSB Urgent Recommendations to NiSource In the November 14, 2018, safety recommendation report, Natural Gas Distribution System Project Development and Review, the NTSB also issued four urgent recommendations to NiSource (NTSB 2018). While the engineering design package for the South Union Street project underwent a constructability review, the review did not identify the impact on pressure regulation and control. The NiSource field engineer who developed the engineering plans told NTSB investigators he developed them without reviewing engineering drawings that documented the regulator sensing lines. Because a comprehensive constructability review, which would require all departments to review each project, along with the seal of approval from a registered P.E., likely would have identified the omission of the regulator sensing lines, thereby preventing the error that led to the accident, the NTSB issued urgent Safety Recommendation P-18-6 to NiSource: Revise the engineering plan and constructability review process across all your subsidiaries to ensure that all applicable departments review documents for accuracy, completeness, and correctness, and that the documents or plans be sealed by a professional engineer prior to commencing work. (P-18-6) (Urgent) In response to this recommendation, NiSource developed and implemented a new Gas Standard (GS 2810.050) detailing the stakeholder reviews that are required for design capital projects or projects where pipeline facilities are installed or replaced. The Gas Standard details the steps in project design and execution when additional stakeholder input is necessary to ensure safe work performance. With this Gas Standard, the use of an enhanced Constructability/Safety Review form is required across the organization to provide additional assurance that all applicable departments review project plans prior to the start of work. Since January 1, 2019, NiSource requires that all relevant construction documents for complex projects are being sealed by a P.E. prior to the start of construction. In meetings with the NTSB, NiSource discussed that there were potentially large numbers of routine main extensions involving standard tie-ins, emergency main replacements requiring standard tie-ins, or new and replacement service lines, and that completing all of these standard designs would delay implementing this recommendation beyond what is appropriate given its urgent classification. Therefore, although NiSource agreed that construction work that could pose a material risk to public safety needed P.E. review and approval prior to commencing construction, NiSource developed criteria for when review by a P.E. is not necessary. In GS 2810.050, NiSource defines complex projects requiring that documents or plans be sealed by a P.E. as follows: • Plans for installation or replacement of transmission-class pipelines or distribution mains with an MAOP equal to or greater than 200 psig • Plans for the installation of or replacement of distribution mains with more than two tie-ins • Plans for the installation of pipelines requiring a temporary bypass ??Projects which involve a change in system pressure • Plans for the installation of distribution services requiring the interruption of natural gas flow to the adjacent transmission lines and/or distribution main • Plans for nonstandard new points of delivery and district regulator stations • Plans for regulator station work that require an interruption of natural gas flow on the inlet or outlet transmission lines and/or distribution mains The development and implementation of GS 2810.050, including the requirement that construction documents and plans be sealed by a P.E., satisfies Safety Recommendation P-18-6 which is classified “Closed- Acceptable Action.” NiSource engineering plans used during the construction work did not document the location of regulator sensing lines. The NTSB believes that had accurate alignment sheets with comprehensive system information been prominently available and required within the toolsets used by the engineers, and diligently reviewed for completeness and technical/safety risks by engineering supervisors, the work package and construction activity plans would have accounted for the regulator sensing lines and prioritized their relocation before abandoning the cast iron main. As a result, the NTSB made the following urgent safety recommendation to NiSource: Review and ensure that all records and documentation of your natural gas systems are traceable, reliable, and complete. (P-18-7) (Urgent) In its May 10, 2019, letter, NiSource responded it had completed locating, marking, and mapping control (regulator-sensing) lines at all 2,072 low-pressure regulator runs across its system. NiSource said that these facilities are depicted in isometric drawings and are visible in its GIS. In addition, NiSource contracted with a third-party natural gas engineering firm to verify the assets required to safely operate its low-pressure natural gas systems and ensure these assets are clearly indicated on relevant maps and records. On July 22, 2019, Safety Recommendation P-18-7 was classified CLOSED-ACCEPTABLE ACTION.

From: NiSource, Inc. (formerly Columbia Gas)
To: NTSB
Date: 7/29/2019
Response: -From Joe Hamrock, President and CEO: On November 14, 2018, the NTSB issued four urgent safety recommendations to NiSource Inc. based upon the NTSB's investigation thus far of the September 13, 2018, gas overpressurization in Merrimack Valley, Massachusetts. We’ve since issued our initial response, outlined our commitments to meeting the recommendations and provided follow-up progress reports, including our recommendation to close two of the four recommendations. Since the Merrimack Valley incident, NiSource has implemented significant changes to improve pipeline safety and enhance practices related to project planning and execution, all of which further protect our customers, communities and employees. On May 10, 2019, NiSource submitted a letter to the NTSB constituting closure of urgent recommendations P-18-007 and P- 18-009. On July 22, 2019, NTSB responded to that letter notifying NiSource that urgent recommendations P-18-007 and P-18-009 had been “Closed-Acceptable Action.” Herein, we describe why our work constitutes closure of the remaining two recommendations, P-18-006 and -008. NiSource has completed its initial asset risk review and assessment, and continues to mature its probabilistic risk assessments to understand the spectrum of pipeline safety risks across the organization. This initial review has proven invaluable as NiSource continues to make progress on implementing our Safety Management System and places added emphasis on identifying and evaluating risks according to probability of occurrence and level of impact. The asset review that is performed will inform future data collection efforts to ensure that NiSource is tracking the appropriate risks and events for trends and analysis. Additionally, the review of critical assets and associated risks will inform the NiSource business planning process to ensure that funds are allocated to mitigate the most significant risks across the organization. An overview of NiSource’s Asset Assessment and Probabilistic Risk Assessment is included with this correspondence for your review. NiSource has developed and implemented a critical management of change procedure through the enhanced Gas Standard 1680.010 and written tie-in plan template. These documents were shared as part of the NiSource letter dated May 10, 2019, recommending closure of urgent recommendation P 18-009. Above and beyond the scope of the recommendation, NiSource continues to develop the Safety Management System, including NiSource enterprise-wide Management of Change governance documentation.

From: NTSB
To: NiSource, Inc. (formerly Columbia Gas)
Date: 7/22/2019
Response: We note that you have improved your MOC process by using Gas Standard 1680.010, “Tie Ins and Tapping Pressurized Pipelines,” and you now require the use of a written tie-in plan template. We further note that you continue to develop and implement a safety management system (SMS), which includes documentation of enterprise-wide MOC governance. As part of your SMS development activities, you initiated asset review and probabilistic risk assessments that focus on improving risk analysis, identification, and mitigation. Finally, you have developed and implemented an MOC procedure for your construction employees and contractors that details the steps needed to ensure safety on a project during a change in personnel. During our March 4, 2019, and April 18, 2019, meetings, we discussed your efforts to develop a company-wide SMS consistent with American Petroleum Institute Recommended Practice 1173, “Pipeline Safety Management System.” We were pleased to see the work you are doing to develop your SMS, as well as your plans to share lessons learned with other members of the natural gas distribution industry. We believe that, in addition to addressing issues specifically discussed in these recommendations, developing and implementing an SMS can significantly improve the safety of all operations within the natural gas distribution industry. Pending completion of your initial asset review and probabilistic risk assessments, Safety Recommendation P-18-8 remains classified OPEN--ACCEPTABLE RESPONSE.

From: NiSource, Inc. (formerly Columbia Gas)
To: NTSB
Date: 5/10/2019
Response: -From Joe Hamrock, President and CEO: NiSource is near completion of its initial asset review and probabilistic risk assessment efforts focused on improving risk identification, analysis and mitigation efforts across the organization. The result of this effort will be prioritization of risks based on the analysis performed across all asset classes to ensure focus is appropriately placed on mitigating those high priority risks. A critical management of change procedure was developed and implemented through the enhanced Gas Standard 1680.010 and written tie-in plan template as stated in the NiSource response to P-18-009. NiSource also continues to develop and implement a Safety Management System, including enterprise-wide Management of Change governance documentation.

From: NiSource, Inc. (formerly Columbia Gas)
To: NTSB
Date: 3/15/2019
Response: -From Joe Hamrock, President and CEO: NiSource Response: NiSource will engage third party experts to conduct gas system risk review with NiSource subject matter experts and key executives. The review will focus on risk identification, latent system risks, risk analysis, failures and failure sequences (cut set), risk end states, fault tree development, failure modes and effects analysis, event trees, dominant risk drivers, failures and failure combinations, risk mitigation /management options, risk register development and population, risk reduction action plan development and actions options, assessment of low probability- high consequence events and common mode failure threats. NiSource will strengthen its Management of Change (MOC) procedures with the adoption of API RP 1173 and developing and implementing a Pipeline Safety Management System in 2019. Identified system threats that can result in a common mode of failure and high consequence events will be integrated into work risk reviews and procedures enhancements. Progress to Date: As part of SMS development, we have launched asset review and probabilistic risk assessment teams focused on improving risk analysis, identification and mitigation efforts across the organization. These teams have partnered with advisors who have expertise in these practices. Additionally, SMS development is helping mature MOC procedures as safety excellence and risk mitigation strategies are defined. We developed and deployed an MOC procedure to our construction employees and contractors that details steps needed to ensure safety on a project during a change in personnel. We developed new enhanced tapping and tie-in procedures that outline stakeholder engagement, risk identification, roles and responsibilities and MOC principles. Next Steps: Continue SMS development across NiSource to bolster risk review and MOC processes and procedures. Develop and implement additional MOC procedures to be used during construction planning and execution phases. Implement enhanced tapping and tie-in procedures.

From: NTSB
To: NiSource, Inc. (formerly Columbia Gas)
Date: 2/19/2019
Response: We note that you will engage third-party experts to work with your staff to conduct risk reviews of your gas systems. We further note that you will strengthen your MOC procedures by adopting American Petroleum Institute Recommended Practice 1173, “Pipeline Safety Management System.” Pending completion of your risk review and implementation of a PSMS, Safety Recommendation P-18-8 is classified OPEN--ACCEPTABLE RESPONSE.

From: NiSource, Inc. (formerly Columbia Gas)
To: NTSB
Date: 12/14/2018
Response: -Joe Hamrock, President and CEO: NiSource will engage third party experts to conduct gas system risk review with NiSource subject matter experts and key executives. The review will focus on risk identification, latent system risks, risk analysis, failures and failure sequences (cut set), risk end states, fault tree development, failure modes and effects analysis, event trees, dominant risk drivers, failures and failure combinations, risk mitigation /management options, risk register development and population, risk reduction action plan development and actions options, assessment of low probability- high consequence events and common mode failure threats. NiSource will strengthen its Management of Change (MOC) procedures with the adoption of API RP 1173 and developing and implementing a Pipeline Safety Management System in 2019. Identified system threats that can result in a common mode of failure and high consequence events will be integrated into work risk reviews and procedures enhancements.

From: NTSB
To: NiSource, Inc. (formerly Columbia Gas)
Date: 11/15/2018
Response: 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. On November 14, 2018, the National Transportation Safety Board (NTSB) adopted its safety recommendation report, Natural Gas Distribution System Project Development and Review PSR 18/02. The details of this safety recommendation report may be found at http://www.ntsb.gov. Among the safety recommendations are four urgent safety recommendations issued to NiSource, Inc., which can be found on page 7 of the report. The NTSB is vitally interested in these recommendations because they are designed to prevent accidents and save lives. We would appreciate a response within 30 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. We encourage you to submit your response to correspondence@ntsb.gov. If it exceeds 10 megabytes, including attachments, 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.