# NTSB Safety Recommendation P-18-006 **Citation:** P-18-006 **Type / status:** guidance / guidance **Agency:** National Transportation Safety Board **Effective:** 2018-11-15 **Published:** 2018-11-15 TO NISOURCE: Revise the engineering plan and constructability review process across all of your subsidiaries to ensure that all applicable departments review construction documents for accuracy, completeness, and correctness, and that the documents or plans be sealed by a professional engineer prior to commencing work. (Urgent) ## Document text NTSB safety recommendation P-18-006. TO NISOURCE: Revise the engineering plan and constructability review process across all of your subsidiaries to ensure that all applicable departments review construction documents for accuracy, completeness, and correctness, and that the documents or plans be sealed by a professional engineer prior to commencing work. (Urgent) Priority: CLASS I Overall Status: Closed - Acceptable Action Issued Date: 2018-11-15 Adopted Date: 2018-11-14 Overall Date Closed: 2019-10-24 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. Probable Cause: The National Transportation Safety Board determines that the probable cause of the overpressurization of the natural gas distribution system and the resulting fires and explosions was Columbia Gas of Massachusetts’ weak engineering management that did not adequately plan, review, sequence, and oversee the construction project that led to the abandonment of a cast iron main without first relocating regulator sensing lines to the new polyethylene main. Contributing to the accident was a low-pressure natural gas distribution system designed and operated without adequate overpressure protection. Ntsbnumber: PLD18MR003 Report Number: PSR-18-02 Addressee Name: NiSource, Inc. (formerly Columbia Gas) Addressee Status: Closed - Acceptable Action Addressee Date Closed: 2019-10-24 Addressee Organization Type: P-Private Industry Communication Date: 2019-10-24 Communication Type: Transmittal Letter Communication Contents: 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. Addressee Organization Type: P-Private Industry Communication Date: 2019-10-24 Communication Type: Transmittal Letter Communication Contents: 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. Addressee Organization Type: P-Private Industry Communication Date: 2018-11-15 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 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. Addressee Organization Type: P-Private Industry Communication Date: 2023-10-27 Communication Type: NPRM Response Communication Contents: The National Transportation Safety Board (NTSB) has reviewed the Pipeline and Hazardous Materials Safety Administration’s (PHMSA) notice of proposed rulemaking (NPRM), titled “Pipeline Safety: Safety of Gas Distribution Pipelines and Other Pipeline Safety Initiatives,” published at 88 Federal Register 61746 on September 7, 2023. The NPRM proposes amendments to Title 49 Code of Federal Regulations (CFR) Parts 191, 192, and 198 in response to congressional mandates in the Leonel Rondon Pipeline Safety Act and an NTSB safety recommendation aimed at preventing catastrophic incidents resulting from overpressurization of low pressure gas distribution systems. The NTSB investigated two natural gas accidents that resulted in recommendations that are applicable to this NPRM. We describe these investigations and offer comments on the following topic areas: Clarifications and Updates to Distribution Integrity Management Program Plans, Updates to Emergency Response Communications, Updates to Operations and Maintenance Procedural Manuals, and Requirements for New Regulator Stations. Related NTSB Investigations 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. In the 2 days before the explosion, two gas related incidents occurred on the same block at houses that were served by the same natural gas main, each resulting in one injury and significant structural damage. We 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 the operator’s investigation of the two related incidents that occurred in the 2 days before the explosion. In September 2018, the NTSB investigated the overpressurization of a natural gas distribution system in Merrimack Valley, Massachusetts, which resulted in fires and explosions, 1 fatality, 22 individuals being taken to local hospitals, 5 destroyed homes, 131 damaged structures, and the evacuation of 50,000 residents. We determined that the probable cause of the accident was the operator’s failure to adequately plan, review, sequence, and oversee a pipeline construction project. Updates to Operations and Maintenance (O&M) Procedural Manuals NPRM Commentary In the NPRM, PHMSA proposes updates to O&M procedural manuals to (1) account for the response and correction of overpressurization indications, (2) ensure a management of change process when an operator makes certain changes that could impact the integrity or safety of a gas distribution system, and (3) require that operators ensure qualified personnel review and certify certain construction plans. In the discussion for the third proposed update, the NPRM cites Safety Recommendation P 19 16, which recommends that states require professional engineer (PE) approval for natural gas infrastructure projects. The NPRM expresses concern that the lack of PEs in states could cause delays in critical construction projects; therefore, PHMSA proposes to allow individuals other than licensed PEs to be considered qualified to review construction plans. NTSB Comment We focus on the third proposed change, which would add a requirement that operators ensure qualified personnel review certain construction projects. Our Merrimack Valley investigation indicated that PE approval should be an essential component of construction plans that affect public safety. In the investigation, we noted that had the comprehensive constructability review of the operator’s pipeline construction project plan required a PE’s seal, it would have likely identified a critical omission in the plan and prevented the error that led to the accident. Our investigation recognized that a PE license is a valued credential, especially for engineering projects affecting public safety. The investigation report provides several reasons that we value the PE credential, noting that (1) it conveys that the holder maintains and demonstrates technical competency; (2) PEs are bound to a code of ethics, which creates a duty to hold public safety, health, and welfare paramount and to perform services only in the areas of their competence; and (3) PEs are personally accountable for the work they approve and stamp, and they must exercise responsible charge over all aspects of the work. As a result of our investigation, we issued three safety recommendations on this topic. We issued Safety Recommendation P 18 5 to the Commonwealth of Massachusetts to eliminate the PE licensure exemption for public utility work and require a PE’s seal on public utility engineering drawings. After Massachusetts enacted a law requiring that licensed PEs review and approve engineering plans developed by or on behalf of natural gas companies, we classified the recommendation as Closed—Acceptable Action. We also issued Safety Recommendation P 18 6 to the operator to revise its engineering plan and constructability review process to ensure that all applicable departments review construction plans and that a PE seals these plans before starting work. After the operator developed criteria for when PE approval is necessary and when it is not, we classified the recommendation as Closed—?Acceptable Action. Finally, we issued Safety Recommendation P 19 16 to 31 states that allow exemptions to PE approval and stamping for natural gas infrastructure projects, calling for them to remove the exemption so that all future natural gas infrastructure projects require licensed PE approval and stamping. One of the three states that has satisfied this recommendation, Maryland, did so by removing the PE exemption and developing criteria for “covered” projects, which require PE approval, and for “noncovered” projects, which can be reviewed by a relevant, qualified person. The NTSB believes that the NPRM’s third proposed change to O&M procedural manuals, which would require that qualified personnel, rather than PEs, review and certify certain construction plans, does not address the intent of our safety recommendations on this topic. We acknowledge that not all projects may require PE approval, such as those that do not pose a risk to public safety. Therefore, in our view, PHMSA and state regulators should develop specific criteria for determining the types of projects that require PE approval and those that do not. We encourage PHMSA to include this approach in the final rule. Summary The NTSB supports many of the NPRM’s proposed revisions to its pipeline safety regulations. However, we believe that the proposal has some shortcomings and encourage PHMSA to address our comments in its final rulemaking. Thank you for the opportunity to comment on this notice. Addressee Organization Type: P-Private Industry Communication Date: 2018-12-14 Communication Type: Official Correspondence Communication Contents: -Joe Hamrock, President and CEO: NiSource will review our Engineering and Construction Gas Standards and our Constructability Review processes and implement changes to ensure that all internal operations departments are required to participate in Constructability Reviews and sign off that all documents used for construction are accurate and complete. NiSource will have a third party firm with gas industry expertise review and validate the above modified engineering and construction standards. All relevant construction documents and plans for construction work that could pose a material risk to public safety will be sealed by a professional engineer prior to commencing construction work. This work would include new or replacement mains involving multiple tie-ins, new or replacement of major components of a point of delivery, district regulator stations or large volume customer measurement and regulation station. For routine main extensions involving a standard tie-in, emergency main replacements requiring standard tie-ins and new and replacement service lines, NiSource will develop standard designs and construction procedures and have them reviewed and approved by a professional engineer. Addressee Organization Type: P-Private Industry Communication Date: 2019-03-15 Communication Type: Official Correspondence Communication Contents: -From Joe Hamrock, President and CEO: NiSource will review our Engineering and Construction Gas Standards and our Constructability Review processes and implement changes to ensure that all internal operations departments are required to participate in Constructability Reviews and sign off that all documents used for construction are accurate and complete. NiSource will have a third party firm with gas industry expertise review and validate the above modified engineering and construction standards. All relevant construction documents and plans for construction work that could pose a material risk to public safety will be sealed by a professional engineer (PE) prior to commencing construction work. This work would include new or replacement mains involving multiple tie-ins, new or replacement of major components of a point of delivery, district regulator stations or large volume customer measurement and regulation station. For routine main extensions involving a standard tie-in, emergency main replacements requiring standard tie-ins and new and replacement service lines, NiSource will develop standard designs and construction procedures and have them reviewed and approved by a professional engineer. Progress to Date: Since January 1, 2019, complex projects are being reviewed and sealed by a PE prior to approval. Standard designs for routine projects are in development with a cross-functional team working with PEs on completeness. Constructability Review enhancements are ongoing to add stakeholder participation and guidance based on project design criteria. NiSource has engaged a third-party engineering firm, TRC Solutions, to conduct a review of engineering and construction standards. Next Steps: Complete the development of standard designs for routine projects and ensure the addition of a PE’s seal. Review the recommendations to be made by TRC Solutions and incorporate enhancements as appropriate. Finalize enhancements to the Constructability Review, publish the new version, train users for appropriate use and ensure adoption. Addressee Organization Type: P-Private Industry Communication Date: 2019-05-10 Communication Type: Official Correspondence Communication Contents: -From Joe Hamrock, President and CEO: NiSource has drafted a comprehensive procedure for stakeholder review of designed capital projects which includes an enhanced Constructability Review process that assists the project engineer with identifying the stakeholders required to participate in the review and to otherwise be consulted during project planning. It is anticipated that the enhanced stakeholder review process will be implemented over the next several weeks. Additionally, as stated in the NiSource response to P-18-009, the written tie-in plan template has been enhanced to include multiple briefings where critical stakeholders including Engineering, the project execution crew, and Measurement & Regulation review the tie-in plan for risks and accuracy. These critical project milestones and other project stakeholder reviews are included in a draft procedure detailing project criteria where each is performed. All relevant construction documents and plans for construction work for “complex” projects are being sealed by a professional engineer prior to commencing construction work. Above and beyond the scope of the recommendation, NiSource continues to consider ways to review and validate Standard Designs for “non-complex” or “routine” mainline projects. Addressee Organization Type: P-Private Industry Communication Date: 2019-07-29 Communication Type: Official Correspondence Communication Contents: -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. As of January 1, 2019, all relevant construction documents and plans for construction work for complex projects are being sealed by a professional engineer prior to commencing construction work. NiSource has incorporated this practice across its seven-state footprint and continues to refine the process for effectiveness. Copies of NiSource project plans sealed by a professional engineer were submitted to the NTSB on April 18, 2019. As outlined in the Gas Standard described below, NiSource defines complex projects as follows: a) Plans for installation or replacement of transmission class pipelines or distribution mains with an MAOP equal to or greater than 200 PSIG. b) Plans for the installation of or replacement of distribution mains with more than two tie-ins. c) Plans for the installation of pipelines requiring a temporary bypass. d) Projects which involve a change in system pressure. e) Plans for the installation of distribution services requiring the interruption of gas flow to the adjacent transmission lines and/or distribution main. f) Plans for non-standard new points of delivery and district regulator stations. g) Plans for regulator station work that requires an interruption of gas flow on the inlet or outlet transmission lines and/or distribution mains. Additionally, NiSource has 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. This 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, 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. Copies of both the Gas Standard 2810.050 and enhanced Constructability/Safety Review form are included with this correspondence for your review. Addressee Organization Type: P-Private Industry Communication Date: 2019-02-19 Communication Type: Official Correspondence Communication Contents: We note that you plan to review your engineering and construction gas standards and your constructability review processes and implement changes to ensure that all internal operations departments participate in constructability reviews and that all construction documents are accurate and complete. You also plan to have a third-party firm with gas industry expertise review and validate your engineering and construction standards once they have been modified. We further note that you will require that a PE seal all relevant documents and plans for construction work that could pose a risk to public safety. For routine main extensions involving a standard tie in, emergency main replacements requiring standard tie-ins, and new and replacement service lines, you plan to develop standard designs and construction procedures that will be reviewed and approved by a PE. Pending completion of these reviews and revisions, Safety Recommendation P 18-6 is classified OPEN--ACCEPTABLE RESPONSE. Addressee Organization Type: P-Private Industry Communication Date: 2019-07-22 Communication Type: Official Correspondence Communication Contents: We note that, since January 1, 2019, PEs have been reviewing and sealing complex project plans prior to their approval, a cross-functional team is working with PEs to develop standard designs for routine projects, and you are enhancing constructability reviews so stakeholders may participate and suggest guidance based on project design criteria. Additionally, you have awarded a contract to a third-party engineering firm to review your engineering and construction standards, and you plan to incorporate the firm’s recommended revisions, as appropriate. Finally, we note that you intend to finalize and publish your constructability review process and train your staff on how to implement it. Discussion during our March 4, 2019, and April 18, 2019, meetings centered extensively on how to determine when a project is complex enough to warrant PE review and seal. We understand your concern that there are potentially large numbers of routine main extensions involving a standard tie-in, emergency main replacements requiring standard tie-ins, and new and replacement service lines, and that completing all of these standard designs may delay your implementation of this recommendation beyond what is appropriate, given its urgent classification. Therefore, although you agree that construction work that could pose a material risk to public safety needs PE review and approval prior to commencing, you believe it would be more efficient to also develop criteria for when such a review is not necessary. We believe this is a reasonable way to address your concerns, and we ask that you tell us what criteria you develop and how the guidance will be shared with your staff. Pending your completion of the activities that you described and our review of your guidance for when PE review and approval may not be necessary, Safety Recommendation P-18-6 remains classified OPEN--ACCEPTABLE RESPONSE. ## Provenance - Official: Yes - Source: - Source ID: `ntsb-pipeline` - SHA-256: `4bf8eebf3242faafc19e557b71139f3d94ef8d5ea9f9ecae6b6582ee3ef0311d` - Retrieved: 2026-08-20T04:57:24.741Z - Exported: 2026-08-22T19:20:30.754Z - Document slug: `ntsb-recommendation-p-18-006` ### Source metadata ```json { "recordKind": "ntsb_safety_recommendation", "safetyRecommendationNumber": "P-18-006", "recommendationMode": "Pipeline", "topicMode": "Pipeline", "ntsbNumber": "PLD18MR003", "priority": "CLASS I", "overallStatus": "Closed - Acceptable Action", "overallStatusAcronym": "CAA", "overallDateClosed": "2019-10-24", "lastModifiedDate": "2023-10-30", "reportNumber": "PSR-18-02", "reportUrl": "https://www.ntsb.gov/investigations/Pages/PLD18MR003.aspx", "transmittalLetterUrl": "http://www.ntsb.gov/safety/safety-recs/recletters/P-18-005-009.pdf", "addressees": [ { "addresseeName": "NiSource, Inc. (formerly Columbia Gas)", "addresseeStatusAcronym": "CAA", "addresseeStatus": "Closed - Acceptable Action", "addresseeDateClosed": "2019-10-24", "addresseeDetails": [ { "addresseeAcronym": null, "addresseeOrganizationType": "P-Private Industry", "isFromNtsb": true, "communicationDate": "2019-10-24", "communicationType": "Transmittal Letter", "communicationContents": "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\r\n\r\nIn 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.\r\n\r\nBecause 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: \r\n\r\nRevise 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) \r\nIn 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. \r\n\r\nSince 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: \r\n\r\n• Plans for installation or replacement of transmission-class pipelines or distribution mains with an MAOP equal to or greater than 200 psig \r\n• Plans for the installation of or replacement of distribution mains with more than two tie-ins \r\n• Plans for the installation of pipelines requiring a temporary bypass\r\n\r\n??Projects which involve a change in system pressure \r\n• Plans for the installation of distribution services requiring the interruption of natural gas flow to the adjacent transmission lines and/or distribution main \r\n• Plans for nonstandard new points of delivery and district regulator stations \r\n• Plans for regulator station work that require an interruption of natural gas flow on the inlet or outlet transmission lines and/or distribution mains \r\n\r\nThe 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." }, { "addresseeAcronym": null, "addresseeOrganizationType": "P-Private Industry", "isFromNtsb": true, "communicationDate": "2019-10-24", "communicationType": "Transmittal Letter", "communicationContents": "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\r\n\r\nIn 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.\r\n\r\nBecause 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: \r\n\r\nRevise 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) \r\nIn 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. \r\n\r\nSince 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: \r\n\r\n• Plans for installation or replacement of transmission-class pipelines or distribution mains with an MAOP equal to or greater than 200 psig \r\n• Plans for the installation of or replacement of distribution mains with more than two tie-ins \r\n• Plans for the installation of pipelines requiring a temporary bypass\r\n\r\n??Projects which involve a change in system pressure \r\n• Plans for the installation of distribution services requiring the interruption of natural gas flow to the adjacent transmission lines and/or distribution main \r\n• Plans for nonstandard new points of delivery and district regulator stations \r\n• Plans for regulator station work that require an interruption of natural gas flow on the inlet or outlet transmission lines and/or distribution mains \r\n\r\nThe 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." }, { "addresseeAcronym": null, "addresseeOrganizationType": "P-Private Industry", "isFromNtsb": true, "communicationDate": "2018-11-15", "communicationType": "Transmittal Letter", "communicationContents": "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. \r\nOn 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.\r\nAmong the safety recommendations are four urgent safety recommendations issued to NiSource, Inc., which can be found on page 7 of the report.\r\nThe 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." }, { "addresseeAcronym": null, "addresseeOrganizationType": "P-Private Industry", "isFromNtsb": true, "communicationDate": "2023-10-27", "communicationType": "NPRM Response", "communicationContents": "The National Transportation Safety Board (NTSB) has reviewed the Pipeline and Hazardous Materials Safety Administration’s (PHMSA) notice of proposed rulemaking (NPRM), titled “Pipeline Safety: Safety of Gas Distribution Pipelines and Other Pipeline Safety Initiatives,” published at 88 Federal Register 61746 on September 7, 2023. The NPRM proposes amendments to Title 49 Code of Federal Regulations (CFR) Parts 191, 192, and 198 in response to congressional mandates in the Leonel Rondon Pipeline Safety Act and an NTSB safety recommendation aimed at preventing catastrophic incidents resulting from overpressurization of low pressure gas distribution systems. \r\n\r\nThe NTSB investigated two natural gas accidents that resulted in recommendations that are applicable to this NPRM. We describe these investigations and offer comments on the following topic areas: Clarifications and Updates to Distribution Integrity Management Program Plans, Updates to Emergency Response Communications, Updates to Operations and Maintenance Procedural Manuals, and Requirements for New Regulator Stations.\r\n\r\nRelated NTSB Investigations \r\nIn 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. In the 2 days before the explosion, two gas related incidents occurred on the same block at houses that were served by the same natural gas main, each resulting in one injury and significant structural damage. We 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 the operator’s investigation of the two related incidents that occurred in the 2 days before the explosion. \r\nIn September 2018, the NTSB investigated the overpressurization of a natural gas distribution system in Merrimack Valley, Massachusetts, which resulted in fires and explosions, 1 fatality, 22 individuals being taken to local hospitals, 5 destroyed homes, 131 damaged structures, and the evacuation of 50,000 residents. We determined that the probable cause of the accident was the operator’s failure to adequately plan, review, sequence, and oversee a pipeline construction project.\r\n\r\nUpdates to Operations and Maintenance (O&M) Procedural Manuals\r\n\r\nNPRM Commentary\r\n\r\n\tIn the NPRM, PHMSA proposes updates to O&M procedural manuals to (1) account for the response and correction of overpressurization indications, (2) ensure a management of change process when an operator makes certain changes that could impact the integrity or safety of a gas distribution system, and (3) require that operators ensure qualified personnel review and certify certain construction plans. \r\n\r\nIn the discussion for the third proposed update, the NPRM cites Safety Recommendation P 19 16, which recommends that states require professional engineer (PE) approval for natural gas infrastructure projects. The NPRM expresses concern that the lack of PEs in states could cause delays in critical construction projects; therefore, PHMSA proposes to allow individuals other than licensed PEs to be considered qualified to review construction plans.\r\n\r\nNTSB Comment\r\n\r\nWe focus on the third proposed change, which would add a requirement that operators ensure qualified personnel review certain construction projects. \r\n\r\nOur Merrimack Valley investigation indicated that PE approval should be an essential component of construction plans that affect public safety. In the investigation, we noted that had the comprehensive constructability review of the operator’s pipeline construction project plan required a PE’s seal, it would have likely identified a critical omission in the plan and prevented the error that led to the accident. \r\n\r\nOur investigation recognized that a PE license is a valued credential, especially for engineering projects affecting public safety. The investigation report provides several reasons that we value the PE credential, noting that (1) it conveys that the holder maintains and demonstrates technical competency; (2) PEs are bound to a code of ethics, which creates a duty to hold public safety, health, and welfare paramount and to perform services only in the areas of their competence; and (3) PEs are personally accountable for the work they approve and stamp, and they must exercise responsible charge over all aspects of the work. As a result of our investigation, we issued three safety recommendations on this topic.\r\n\r\nWe issued Safety Recommendation P 18 5 to the Commonwealth of Massachusetts to eliminate the PE licensure exemption for public utility work and require a PE’s seal on public utility engineering drawings. After Massachusetts enacted a law requiring that licensed PEs review and approve engineering plans developed by or on behalf of natural gas companies, we classified the recommendation as Closed—Acceptable Action. \r\n\r\nWe also issued Safety Recommendation P 18 6 to the operator to revise its engineering plan and constructability review process to ensure that all applicable departments review construction plans and that a PE seals these plans before starting work. After the operator developed criteria for when PE approval is necessary and when it is not, we classified the recommendation as Closed—?Acceptable Action. \r\n\r\nFinally, we issued Safety Recommendation P 19 16 to 31 states that allow exemptions to PE approval and stamping for natural gas infrastructure projects, calling for them to remove the exemption so that all future natural gas infrastructure projects require licensed PE approval and stamping. One of the three states that has satisfied this recommendation, Maryland, did so by removing the PE exemption and developing criteria for “covered” projects, which require PE approval, and for “noncovered” projects, which can be reviewed by a relevant, qualified person. \r\n\r\nThe NTSB believes that the NPRM’s third proposed change to O&M procedural manuals, which would require that qualified personnel, rather than PEs, review and certify certain construction plans, does not address the intent of our safety recommendations on this topic. We acknowledge that not all projects may require PE approval, such as those that do not pose a risk to public safety. Therefore, in our view, PHMSA and state regulators should develop specific criteria for determining the types of projects that require PE approval and those that do not. We encourage PHMSA to include this approach in the final rule. \r\n\r\nSummary\r\n\r\n\tThe NTSB supports many of the NPRM’s proposed revisions to its pipeline safety regulations. However, we believe that the proposal has some shortcomings and encourage PHMSA to address our comments in its final rulemaking.\r\n\t\r\nThank you for the opportunity to comment on this notice." }, { "addresseeAcronym": null, "addresseeOrganizationType": "P-Private Industry", "isFromNtsb": false, "communicationDate": "2018-12-14", "communicationType": "Official Correspondence", "communicationContents": "-Joe Hamrock, President and CEO: NiSource will review our Engineering and Construction Gas Standards and our Constructability Review processes and implement changes to ensure that all internal operations departments are required to participate in Constructability Reviews and sign off that all documents used for construction are accurate and complete.\r\n\r\nNiSource will have a third party firm with gas industry expertise review and validate the above modified engineering and construction standards. All relevant construction documents and plans for construction work that could pose a material risk to public safety will be sealed by a professional engineer prior to commencing construction work. This work would include new or replacement mains involving multiple tie-ins, new or replacement of major components of a point of delivery, district regulator stations or large volume customer measurement and regulation station. For routine main extensions involving a standard tie-in, emergency main replacements requiring standard tie-ins and new and replacement service lines, NiSource will develop standard designs and construction procedures and have them reviewed and approved by a professional engineer." }, { "addresseeAcronym": null, "addresseeOrganizationType": "P-Private Industry", "isFromNtsb": false, "communicationDate": "2019-03-15", "communicationType": "Official Correspondence", "communicationContents": "-From Joe Hamrock, President and CEO: NiSource will review our Engineering and Construction Gas Standards and our Constructability Review processes and implement changes to ensure that all internal operations departments are required to participate in Constructability Reviews and sign off that all documents used for construction are accurate and complete.\r\n\r\nNiSource will have a third party firm with gas industry expertise review and validate the above modified engineering and construction standards. All relevant construction documents and plans for construction work that could pose a material risk to public safety will be sealed by a professional engineer (PE) prior to commencing construction work. This work would include new or replacement mains involving multiple tie-ins, new or replacement of major components of a point of delivery, district regulator stations or large volume customer measurement and regulation station. For routine main extensions involving a standard tie-in, emergency main replacements requiring standard tie-ins and new and replacement service lines, NiSource will develop standard designs and construction procedures and have them reviewed and approved by a professional engineer.\r\n\r\nProgress to Date:\r\nSince January 1, 2019, complex projects are being reviewed and sealed by a PE prior to approval.\r\n\r\nStandard designs for routine projects are in development with a cross-functional team working with PEs on completeness. Constructability Review enhancements are ongoing to add stakeholder participation and guidance based on project design criteria.\r\n\r\nNiSource has engaged a third-party engineering firm, TRC Solutions, to conduct a review of engineering and construction standards.\r\n\r\nNext Steps:\r\nComplete the development of standard designs for routine projects and ensure the addition of a PE’s seal.\r\n\r\nReview the recommendations to be made by TRC Solutions and incorporate enhancements as appropriate. Finalize enhancements to the Constructability Review, publish the new version, train users for appropriate use and ensure adoption." }, { "addresseeAcronym": null, "addresseeOrganizationType": "P-Private Industry", "isFromNtsb": false, "communicationDate": "2019-05-10", "communicationType": "Official Correspondence", "communicationContents": "-From Joe Hamrock, President and CEO: NiSource has drafted a comprehensive procedure for stakeholder review of designed capital projects which includes an enhanced Constructability Review process that assists the project engineer with identifying the stakeholders required to participate in the review and to otherwise be consulted during project planning. It is anticipated that the enhanced stakeholder review process will be implemented over the next several weeks.\r\n\r\nAdditionally, as stated in the NiSource response to P-18-009, the written tie-in plan template has been enhanced to include multiple briefings where critical stakeholders including Engineering, the project execution crew, and Measurement & Regulation review the tie-in plan for risks and accuracy. These critical project milestones and other project stakeholder reviews are included in a draft procedure detailing project criteria where each is performed.\r\n\r\nAll relevant construction documents and plans for construction work for “complex” projects are being sealed by a professional engineer prior to commencing construction work. Above and beyond the scope of the recommendation, NiSource continues to consider ways to review and validate Standard Designs for “non-complex” or “routine” mainline projects." }, { "addresseeAcronym": null, "addresseeOrganizationType": "P-Private Industry", "isFromNtsb": false, "communicationDate": "2019-07-29", "communicationType": "Official Correspondence", "communicationContents": "-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. \r\n\r\nSince 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.\r\n\r\n As of January 1, 2019, all relevant construction documents and plans for construction work for complex projects are being sealed by a professional engineer prior to commencing construction work. NiSource has incorporated this practice across its seven-state footprint and continues to refine the process for effectiveness. Copies of NiSource project plans sealed by a professional engineer were submitted to the NTSB on April 18, 2019. As outlined in the Gas Standard described below, NiSource defines complex projects as follows: \r\na) Plans for installation or replacement of transmission class pipelines or distribution mains with an MAOP equal to or greater than 200 PSIG. \r\nb) Plans for the installation of or replacement of distribution mains with more than two tie-ins. \r\nc) Plans for the installation of pipelines requiring a temporary bypass. \r\nd) Projects which involve a change in system pressure. \r\ne) Plans for the installation of distribution services requiring the interruption of gas flow to the adjacent transmission lines and/or distribution main. \r\nf) Plans for non-standard new points of delivery and district regulator stations. \r\ng) Plans for regulator station work that requires an interruption of gas flow on the inlet or outlet transmission lines and/or distribution mains. \r\n\r\nAdditionally, NiSource has 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. This 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, 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. Copies of both the Gas Standard 2810.050 and enhanced Constructability/Safety Review form are included with this correspondence for your review." }, { "addresseeAcronym": null, "addresseeOrganizationType": "P-Private Industry", "isFromNtsb": true, "communicationDate": "2019-02-19", "communicationType": "Official Correspondence", "communicationContents": "We note that you plan to review your engineering and construction gas standards and your constructability review processes and implement changes to ensure that all internal operations departments participate in constructability reviews and that all construction documents are accurate and complete. You also plan to have a third-party firm with gas industry expertise review and validate your engineering and construction standards once they have been modified. We further note that you will require that a PE seal all relevant documents and plans for construction work that could pose a risk to public safety. For routine main extensions involving a standard tie in, emergency main replacements requiring standard tie-ins, and new and replacement service lines, you plan to develop standard designs and construction procedures that will be reviewed and approved by a PE. Pending completion of these reviews and revisions, Safety Recommendation P 18-6 is classified OPEN--ACCEPTABLE RESPONSE." }, { "addresseeAcronym": null, "addresseeOrganizationType": "P-Private Industry", "isFromNtsb": true, "communicationDate": "2019-07-22", "communicationType": "Official Correspondence", "communicationContents": "We note that, since January 1, 2019, PEs have been reviewing and sealing complex project plans prior to their approval, a cross-functional team is working with PEs to develop standard designs for routine projects, and you are enhancing constructability reviews so stakeholders may participate and suggest guidance based on project design criteria. Additionally, you have awarded a contract to a third-party engineering firm to review your engineering and construction standards, and you plan to incorporate the firm’s recommended revisions, as appropriate. Finally, we note that you intend to finalize and publish your constructability review process and train your staff on how to implement it.\r\n\r\nDiscussion during our March 4, 2019, and April 18, 2019, meetings centered extensively on how to determine when a project is complex enough to warrant PE review and seal. We understand your concern that there are potentially large numbers of routine main extensions involving a standard tie-in, emergency main replacements requiring standard tie-ins, and new and replacement service lines, and that completing all of these standard designs may delay your implementation of this recommendation beyond what is appropriate, given its urgent classification. Therefore, although you agree that construction work that could pose a material risk to public safety needs PE review and approval prior to commencing, you believe it would be more efficient to also develop criteria for when such a review is not necessary. We believe this is a reasonable way to address your concerns, and we ask that you tell us what criteria you develop and how the guidance will be shared with your staff. Pending your completion of the activities that you described and our review of your guidance for when PE review and approval may not be necessary, Safety Recommendation P-18-6 remains classified OPEN--ACCEPTABLE RESPONSE." } ] } ], "jurisdiction": "US" } ```