NTSB Safety Recommendation Letter P-19-014 through P-19-018

Page 1Official PDFOctober 24, 2019 The Honorable Howard “Skip” Elliott Administrator Pipeline and Hazardous Materials Safety Administration 1200 New Jersey Ave., SE Washington, DC 20590 The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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. 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 of the date of this letter, 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-19-14 and -15). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 2National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Howard “Skip” Elliott Administrator Pipeline and Hazardous Materials Safety Administration 1200 New Jersey Ave., SE Washington, DC 20590 Dear Mr. Elliott: This letter provides information about the National Transportation Safety Board’s (NTSB) September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendations to the Pipeline and Hazardous Materials Safety Administration. Additional information regarding these recommendations can be found in the noted sections of the report. • Revise Title 49 Code of Federal Regulations Part 192 to require overpressure protection for low-pressure natural gas distribution systems that cannot be defeated by a single operator error or equipment failure. (P-19-14) (See section 3.2.) • Issue an alert to all low-pressure natural gas distribution system operators of the possibility of a failure of overpressure protection; and the alert should recommend that operators use 59529#

Page 32 a failure modes and effects analysis or equivalent structured and systematic method to identify potential failures and take action to mitigate those identified failures. (P-19-15) (See section 3.2.) 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 of the date of this letter, 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-19-14). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman 59529#

Page 4October 24, 2019 The Honorable Kay Ivey Governor of Alabama State Capitol 600 Dexter Ave. Montgomery, AL 36130-2751 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02.. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 5National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Kay Ivey Governor of Alabama State Capitol 600 Dexter Ave. Montgomery, AL 36130-2751 Dear Governor Ivey: 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 the State of Alabama to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems 59529#

Page 62 • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the State of Alabama. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 7October 24, 2019 The Honorable Michael J. Dunleavy Governor of Alaska State Capitol Third Floor PO Box 110001 Juneau, AK 99811-0001 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02.The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division.#

Page 8Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 9National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Michael J. Dunleavy Governor of Alaska State Capitol Third Floor PO Box 110001 Juneau, AK 99811-0001 Dear Governor Dunleavy: 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 the State of Alaska to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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. 59529#

Page 102 As a result of this investigation, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the State of Alaska. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 11October 24, 2019 The Honorable Doug Ducey Governor of Arizona State Capitol 1700 W. Washington St. Phoenix, AZ 85007-2812 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 12National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Doug Ducey Governor of Arizona State Capitol 1700 W. Washington St. Phoenix, AZ 85007-2812 Dear Governor Ducey: 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 the State of Arizona to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems 59529#

Page 132 • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the State of Arizona. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 14October 24, 2019 The Honorable Asa Hutchinson Governor of Arkansas 250 State Capitol 500 Woodlane Ave. Little Rock, AR 72201-3405 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02.The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 15National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Asa Hutchinson Governor of Arkansas 250 State Capitol 500 Woodlane Ave. Little Rock, AR 72201-3405 Dear Governor Hutchinson: 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 the State of Arkansas to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems 59529#

Page 162 • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the State of Arkansas. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 17October 24, 2019 The Honorable Gavin Newsom Governor of California 1303 10th St. Suite 1173 Sacramento, CA 95814-4910 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 18National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Gavin Newsom Governor of California 1303 10th St. Suite 1173 Sacramento, CA 95814-4910 Dear Governor Newsom: 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 the State of California to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems 59529#

Page 192 • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the State of California. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 20October 24, 2019 The Honorable Jared Polis Governor of Colorado 136 State Capitol Denver, CO 80203-1792 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 21National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Jared Polis Governor of Colorado 136 State Capitol Denver, CO 80203-1792 Dear Governor Polis: 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 the State of Colorado to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems 59529#

Page 222 • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the State of Colorado. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 23October 24, 2019 The Honorable Ned Lamont Governor of Connecticut State Capitol 210 Capitol Ave. Hartford, CT 06106-1535 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 24National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Ned Lamont Governor of Connecticut State Capitol 210 Capitol Ave. Hartford, CT 06106-1535 Dear Governor Lamont: 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 the State of Connecticut to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems 59529#

Page 252 • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the State of Connecticut. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 26October 24, 2019 The Honorable Ron DeSantis Governor of Florida State Capitol 400 S. Monroe St. Tallahassee, FL 32399-0001 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02.The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 27National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Ron DeSantis Governor of Florida State Capitol 400 S. Monroe St. Tallahassee, FL 32399-0001 Dear Governor DeSantis: 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 the State of Florida to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems 59529#

Page 282 • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the State of Florida. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 29October 24, 2019 The Honorable Brian P. Kemp Governor of Georgia 111 State Capitol 206 Washington St. Atlanta, GA 30334-1600 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 30National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Brian P. Kemp Governor of Georgia 111 State Capitol 206 Washington St. Atlanta, GA 30334-1600 Dear Governor Kemp: 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 the State of Georgia to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems 59529#

Page 312 • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the State of Georgia. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 32October 24, 2019 The Honorable Brad Little Governor of Idaho State Capitol Building PO Box 83720 Boise, ID 83720-0003 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 33National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Brad Little Governor of Idaho State Capitol Building PO Box 83720 Boise, ID 83720-0003 Dear Governor Little: 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 the State of Idaho to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems 59529#

Page 342 • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the State of Idaho. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 35October 24, 2019 The Honorable J.B. Pritzker Governor of Illinois 207 State House Springfield, IL 62706-9998 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02.. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 36National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable J.B. Pritzker Governor of Illinois 207 State House Springfield, IL 62706-9998 Dear Governor Pritzker: 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 the State of Illinois to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems 59529#

Page 372 • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the State of Illinois. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 38October 24, 2019 The Honorable Kim Reynolds Governor of Iowa 1007 E. Grand Ave. Des Moines, IA 50319-0001 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 39National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Kim Reynolds Governor of Iowa 1007 E. Grand Ave. Des Moines, IA 50319-0001 Dear Governor Reynolds: 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 the State of Iowa to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems 59529#

Page 402 • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the State of Iowa. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 41October 24, 2019 The Honorable Matt Bevin Governor of Kentucky 700 Capitol Ave. Frankfort, KY 40601-3454 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 42National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Matt Bevin Governor of Kentucky 700 Capitol Ave. Frankfort, KY 40601-3454 Dear Governor Bevin: 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 the Commonwealth of Kentucky to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems 59529#

Page 432 • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the Commonwealth of Kentucky. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 44October 24, 2019 The Honorable John Bel Edwards Governor of Louisiana PO Box 94004 Baton Rouge, LA 70804-9004 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 45National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable John Bel Edwards Governor of Louisiana PO Box 94004 Baton Rouge, LA 70804-9004 Dear Governor Edwards: 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 the State of Louisiana to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems 59529#

Page 462 • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the State of Louisiana. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 47October 24, 2019 The Honorable Janet T. Mills Governor of Maine 1 State House Station Augusta, ME 04333-0001 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 48National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Janet T. Mills Governor of Maine 1 State House Station Augusta, ME 04333-0001 Dear Governor Mills: 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 the State of Maine to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems 59529#

Page 492 • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the State of Maine. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 50October 24, 2019 The Honorable Larry Hogan Governor of Maryland 100 State Circle Annapolis, MD 21401-1925 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 51National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Larry Hogan Governor of Maryland 100 State Circle Annapolis, MD 21401-1925 Dear Governor Hogan: 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 the State of Maryland to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems 59529#

Page 522 • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the State of Maryland. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 53October 24, 2019 The Honorable Tim Walz Governor of Minnesota 130 State Capitol St. Paul, MN 55155-1605 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 54National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Tim Walz Governor of Minnesota 130 State Capitol St. Paul, MN 55155-1605 Dear Governor Walz: 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 the State of Minnesota to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems 59529#

Page 552 • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the State of Minnesota. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 56October 24, 2019 The Honorable Phil Bryant Governor of Mississippi PO Box 139 Jackson, MS 39205-0139 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02.. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 57National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Phil Bryant Governor of Mississippi PO Box 139 Jackson, MS 39205-0139 Dear Governor Bryant: 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 the State of Mississippi to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems 59529#

Page 582 • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the State of Mississippi. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 59October 24, 2019 The Honorable Michael L. Parson Governor of Missouri PO Box 720 Jefferson City, MO 65102-0720 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 60National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Michael L. Parson Governor of Missouri PO Box 720 Jefferson City, MO 65102-0720 Dear Governor Parson: 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 the State of Missouri to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems 59529#

Page 612 • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the State of Missouri. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 62October 24, 2019 The Honorable Steve Bullock Governor of Montana State Capitol PO Box 200801 Helena, MT 59620-0801 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02.. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 63National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Steve Bullock Governor of Montana State Capitol PO Box 200801 Helena, MT 59620-0801 Dear Governor Bullock: 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 the State of Montana to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems 59529#

Page 642 • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the State of Montana. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 65October 24, 2019 The Honorable Pete Ricketts Governor of Nebraska PO Box 94848 Lincoln, NE 68509-4848 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02.. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 66National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Pete Ricketts Governor of Nebraska PO Box 94848 Lincoln, NE 68509-4848 Dear Governor Ricketts: 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 the State of Nebraska to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems 59529#

Page 672 • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the State of Nebraska. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 68October 24, 2019 The Honorable Steve Sisolak Governor of Nevada State Capitol 101 N. Carson St. Carson City, NV 89701-5336 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 69National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Steve Sisolak Governor of Nevada State Capitol 101 N. Carson St. Carson City, NV 89701-5336 Dear Governor Sisolak: 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 the State of Nevada to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems 59529#

Page 702 • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the State of Nevada. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 71October 24, 2019 The Honorable Andrew M. Cuomo Governor of New York State Capitol Albany, NY 12224-0343 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 72National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Andrew M. Cuomo Governor of New York State Capitol Albany, NY 12224-0343 Dear Governor Cuomo: 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 the State of New York to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems 59529#

Page 732 • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the State of New York. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 74October 24, 2019 The Honorable Roy Cooper Governor of North Carolina 20301 Mail Service Center Raleigh, NC 27699-0301 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 75National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Roy Cooper Governor of North Carolina 20301 Mail Service Center Raleigh, NC 27699-0301 Dear Governor Cooper: 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 the State of North Carolina to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems 59529#

Page 762 • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the State of North Carolina. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 77October 24, 2019 The Honorable Tom Wolf Governor of Pennsylvania 508 Main Capitol Bldg. Harrisburg, PA 17120-0062 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 78National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Tom Wolf Governor of Pennsylvania 508 Main Capitol Bldg. Harrisburg, PA 17120-0062 Dear Governor Wolf: 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 the Commonwealth of Pennsylvania to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems 59529#

Page 792 • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the Commonwealth of Pennsylvania. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 80October 24, 2019 The Honorable Henry McMaster Governor of South Carolina 1205 Pendleton St. Columbia, SC 29201-3756 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 81National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Henry McMaster Governor of South Carolina 1205 Pendleton St. Columbia, SC 29201-3756 Dear Governor McMaster: 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 the State of South Carolina to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment 59529#

Page 822 • Safety management systems • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the State of South Carolina. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 83October 24, 2019 The Honorable Kristi Noem Governor of South Dakota 500 E. Capitol Ave. Pierre, SD 57501-5001 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 84National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Kristi Noem Governor of South Dakota 500 E. Capitol Ave. Pierre, SD 57501-5001 Dear Governor Noem: 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 the State of South Dakota to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems 59529#

Page 852 • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the State of South Dakota. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 86October 24, 2019 The Honorable Greg Abbott Governor of Texas PO Box 12428 Austin, TX 78711-2428 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 87National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Greg Abbott Governor of Texas PO Box 12428 Austin, TX 78711-2428 Dear Governor Abbott: 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 the State of Texas to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems 59529#

Page 882 • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the State of Texas. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 89October 24, 2019 The Honorable Gary R. Herbert Governor of Utah 350 N. State St. Suite 200 PO Box 142220 Salt Lake City, UT 84114-2220 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02.. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division.#

Page 90Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 91National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Gary R. Herbert Governor of Utah 350 N. State St. Suite 200 PO Box 142220 Salt Lake City, UT 84114-2220 Dear Governor Herbert: 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 the State of Utah to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment 59529#

Page 922 • Safety management systems • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the State of Utah. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 93October 24, 2019 The Honorable Ralph S. Northam Governor of Virginia PO Box 1475 Richmond, VA 23218-1475 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 94National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Ralph S. Northam Governor of Virginia PO Box 1475 Richmond, VA 23218-1475 Dear Governor Northam: 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 the Commonwealth of Virginia to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems 59529#

Page 952 • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the Commonwealth of Virginia. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 96October 24, 2019 The Honorable Mark Gordon Governor of Wyoming Idelman Mansion 2323 Carey Ave. Cheyenne, WY 82002-0010 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 97National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Mark Gordon Governor of Wyoming Idelman Mansion 2323 Carey Ave. Cheyenne, WY 82002-0010 Dear Governor Gordon: 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 the State of Wyoming to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems 59529#

Page 982 • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the 31 states that allow exemptions to professional engineer approval and stamping for natural gas infrastructure projects, including the State of Wyoming. Additional information regarding this recommendation can be found in the noted section of the report. • Remove the exemption so that all future natural gas infrastructure projects require licensed professional engineer approval and stamping. (P-19-16) (See section 3.4.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 99October 24, 2019 The Honorable Charlie Baker Governor of Massachusetts 280 State House Boston, MA 02133-1002 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-16). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 100National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 The Honorable Charlie Baker Governor of Massachusetts 280 State House Boston, MA 02133-1002 Dear Governor Baker: 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 the Commonwealth of Massachusetts Executive Office of Public Safety and Security to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems 59529#

Page 1012 • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to the Commonwealth of Massachusetts Executive Office of Public Safety and Security. Additional information regarding this recommendation can be found in the noted section of the report. • Develop guidance that includes a component for effective communications when deploying mutual aid resources within the first hours of a multi-jurisdictional incident. (P-19-17) (See section 3.5.2.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-17). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 102October 24, 2019 Mr. Joseph Hamrock Chief Executive Officer NiSource, Inc. 801 E. 86th Ave. Merrillville, IN 46410 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. The attached letter from the NTSB Chairman provides information about the NTSB’s September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. The details of this accident investigation and the resulting safety recommendation may be found in the attached report, which can also be accessed at http://www.ntsb.gov. For more information about NTSB and our recommendation process, please see the attached one-page summary. 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 of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations. When replying, please refer to the safety recommendation by number (for example, P-19-18). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, 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. All communications regarding safety recommendations will be stored by the NTSB and viewable by the public. Please do not send privileged or confidential communications in response to this recommendation. Responses marked as confidential or privileged (or similar designations) will be considered nonresponsive. If you have concerns about this protocol, please contact us at ExecutiveSecretariat@ntsb.gov or call (202) 314-6290 and ask to be directed to the Safety Recommendations Division. Executive Secretariat-LRM Office of the Managing Director National Transportation Safety Board 490 L’Enfant Plaza SW Washington, DC 20594 Tel: (202)314-6047 Email: ExecutiveSecretariat@ntsb.gov#

Page 103National Transportation Safety Board Washington, DC 20594 Office of the Chairman October 24, 2019 Mr. Joseph Hamrock Chief Executive Officer NiSource, Inc. 801 E. 86th Ave. Merrillville, IN 46410 Dear Mr. Hamrock: 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 NiSource, Inc. to act on the safety recommendation in this letter because we believe your organization can help reduce the risk of future accidents. For more information about the NTSB and our recommendation process, please see the attached one-page summary. This letter provides information about our September 24, 2019, report Overpressurization of Natural Gas Distribution System, Explosions, and Fires in Merrimack Valley, Massachusetts, September 13, 2018, NTSB/PAR-19/02. 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, we identified the following safety issues: • Adequacy of natural gas regulations • Project documentation • Constructability review • Project management • Risk assessment • Safety management systems 59529#

Page 1042 • Licensed professional engineer approval of natural gas projects • Emergency response Accordingly, the NTSB makes the following safety recommendation to NiSource, Inc. Additional information regarding this recommendation can be found in the noted section of the report. • Review your protocols and training for responding to large-scale emergency events, including providing timely information to emergency responders, appropriately assigning NiSource emergency response duties, performing multi-jurisdictional training exercises, and participating cooperatively with municipal emergency management agencies. (P-19-18) (See section 3.5.3.) The NTSB is vitally interested in this recommendation because it is designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement this recommendation. When replying, please refer to the safety recommendation by number (for example, P-19-18). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply, including attachments, exceeds 20 megabytes, 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. Sincerely, [Original Signed] Robert L. Sumwalt, III Chairman#

Page 105NTSB Recommendations and You The National Transportation Safety Board (NTSB) is an independent federal agency charged with investigating and determining the probable cause of transportation accidents. We do not make regulations, but we do issue recommendations to organizations such as yours when we discover shortcomings in the transportation system that increase the risk of accidents. As a result of our investigative activities, we have issued one or more safety recommendations that we believe you can act on to improve transportation safety. Why did the NTSB issue my organization a safety recommendation? We issue safety recommendations to organizations that can bring about change to reduce the risk of accidents, either through their direct role in the transportation industry, their legislative or regulatory authority, or the significant influence they have among others in the industry. We believe your organization is able to make or influence such changes. What does the NTSB expect of safety recommendation recipients? First and foremost, we encourage you to promptly take the recommended action to improve safety. Because we’re eager to see recommendations implemented before more accidents occur, we follow recipients’ efforts to implement each recommendation. We ask that you update us any time you achieve a significant milestone in your progress toward implementing the attached recommendation(s), or at least annually. We will provide feedback on your efforts by classifying each recommendation as open or closed, acceptable or unacceptable.1 Information about your actions associated with your recommendation(s) is available at our website so that the public can see our combined efforts to improve transportation safety. What should our response to the NTSB include? Please respond to us within 90 days (30 for urgent recommendations) explaining the specific actions you have taken or intend to take in response to the safety recommendation(s), and propose a timeline for completion. We understand organizations today are faced with competing priorities and limited resources, which can make implementing our recommendations a challenge. If, for any reason, you are not able to take the recommended action, or if you believe an alternate action would be more appropriate for your organization, please explain why. When you respond, please provide an e-mail address for future communications. We will review your response and provide feedback. What if my organization doesn’t believe the recommended action is the best way to improve safety? We base our recommendations on the evidence, facts, and circumstances of the accidents we investigate. Sometimes industry leaders identify ways to attain the same safety objective more efficiently, and we encourage recipients to share their ideas with us. In these cases, we will evaluate the alternate means of achieving the safety objective and provide feedback. We believe safety is a collaborative effort, and we’re happy to work with your organization to set goals and make improvements. Why does the NTSB expect us to take action, even though our organization wasn’t responsible for the accident that resulted in the safety recommendation? Our goal is to prevent accidents. Often, the factors we identify as causing or contributing to an accident are not unique— they represent common practices or situations that may be accidents waiting to happen. In such instances, we may make recommendations intended to raise the minimum standard for safety throughout the industry. How do we contact the NTSB to provide updates or obtain further information? Please contact us electronically at executivesecretariat@ntsb.gov. If you wish to send us supporting documentation that, with your response, exceeds 10 megabytes, please contact us at the same e-mail address for instructions. You can also reach our Safety Recommendations staff at (202) 314-6290 (please ask to be directed to the Safety Recommendations Division). 1  For a full description of our safety recommendation classifications, see the Status Explanation page on our website. www.ntsb.gov We look forward to working with you to prevent accidents and save lives!#