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Safety Recommendation Details

Safety Recommendation P-18-007
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: Review and ensure that all records and documentation of your natural gas systems are traceable, reliable, and complete. (Urgent)
Original recommendation transmittal letter: PDF
Overall Status: Open - Acceptable Response
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)
Report #: PSR-18-02
Accident Date: 9/13/2018
Issue Date: 11/15/2018
Date Closed:
Addressee(s) and Addressee Status: NiSource, Inc. (formerly Columbia Gas) (Open - Acceptable Response)
Keyword(s):

Safety Recommendation History
From: NiSource, Inc. (formerly Columbia Gas)
To: NTSB
Date: 5/10/2019
Response: -From Joe Hamrock, President and CEO: NiSource has completed locating, marking and mapping of control (regulator-sensing) lines at all 2,072 low-pressure regulator runs across its seven state footprint. These facilities are depicted in isometric drawings, examples of which were provided to the NTSB during a meeting on April 18, and are visible in the NiSource geographic information system (GIS). NiSource worked with third-party gas engineering firm TRC Solutions to verify the assets required to safely operate its low-pressure gas systems and ensure these assets are clearly indicated on relevant maps and records. The review of critical assets concluded that NiSource maps include visual records with attributes of facilities required to operate the low-pressure systems including but not limited to pipes, valves and pressure regulating stations. The review focused closely on the existence and quality of the updated station drawings showing control lines. This review concluded that those station schematics are traceable, reliable, and complete. Results from this review are documented in a report published by TRC titled, Report on Compliance with NTSB Recommendation - Item #2 - Material Verification Records. NiSource provided this report to the NTSB during a meeting on April 18. Above and beyond the scope of this urgent recommendation, and as part of business planning and overall SMS implementation, NiSource is prioritizing the mapping of control lines on the remaining elevated pressure stations across its seven-state footprint.

From: NiSource, Inc. (formerly Columbia Gas)
To: NTSB
Date: 3/15/2019
Response: -From Joe Hamrock, President and CEO: Only 12 of NiSource's 2,072 low pressure regulator station control lines (sensing lines) remain to be mapped, marked and protected. NiSource is working to complete these remaining lines. NiSource, with assistance from third party experts, will define the assets required to safely operate its low pressure gas systems and check that such assets have records that are traceable, reliable and complete. NiSource will develop a plan to remediate any deficiencies identified. NiSource will conduct a similar review for all of its other gas systems as part of its Safety Management System implementation. Progress to Date: NiSource is nearly complete in marking and protecting our 2,072 low pressure regulator station control lines, with only a few remaining. NiSource engaged a third-party engineering firm, TRC Solutions, to review NiSource’s geographic information system (GIS) and perform a gap analysis of visible and available assets within low pressure systems to recommend enhancements. NiSource is in the midst of implementing a company-wide SMS with the intention of performing similar gap analyses on our other systems. Hundreds of employees are directly engaged in this project. Next Steps: Complete the mapping, marking and protection of the few remaining low pressure regulator station control lines. Perform a thorough low pressure system asset gap analysis with TRC Solutions, who will share findings and recommendations with NiSource. Build plans to enhance GIS and other systems as appropriate.

From: NTSB
To: NiSource, Inc. (formerly Columbia Gas)
Date: 2/19/2019
Response: In our investigation of the Merrimack Valley accident, we learned that the engineering plans used during the construction work did not document the location of regulator-sensing lines, which led to the circumstances that caused the over pressurization of the low-pressure gas distribution lines. We note that you are currently working to map, mark, and protect the remaining 12 of your 2,072 low pressure regulator station control lines (sensing lines) that have not yet been addressed. We further note that you plan to work with third-party experts to define the assets required to safely operate your low-pressure gas systems and ensure that the records for those assets are traceable, reliable, and complete. Additionally, you will develop a plan to remediate any deficiencies you identify. Finally, we note that you plan to conduct a similar review for all of your other gas systems as part of your pipeline safety management system (PSMS). Pending completion of these actions, Safety Recommendation P-18-7 is classified OPEN--ACCEPTABLE RESPONSE.

From: NiSource, Inc. (formerly Columbia Gas)
To: NTSB
Date: 12/14/2018
Response: -Joe Hamrock, President and CEO: Only 12 of NiSource’s 2,072 low pressure regulator station control lines (sensing lines) remain to be mapped, marked and protected. We are working to complete these remaining lines. NiSource, with assistance from third party experts, will define the assets required to safely operate its low pressure gas systems and ensure that such assets have records that are traceable, reliable and complete. NiSource will develop a plan to remediate any deficiencies identified. NiSource will conduct a similar review for all of its other gas systems as part of its Safety Management System implementation.

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.