COLUMBIA GAS TRANSMISSION, LLC — Warning Letter

12022018WL_Warning Letter (Amended)_03302022_(21-231686)_text.pdf, page 1Official PDFAMENDED WARNING LETTER VIA ELECTRONIC MAIL TO: stanley chapman iii@tcenergy.com March 30, 2022 Mr. Stanley Chapman Executive Vice President & President US & Mexico Natural Gas Columbia Gas Transmission, LLC 7000 Louisiana Street Houston, Texas 77002 CPF 1-2022-018-WL Dear Mr. Chapman: On May 10, 2021, Columbia Gas Transmission, LLC (Columbia) submitted to PHMSA a letter related to Safety-Related Condition Reports. A representative of the Pipeline and Hazardous Materials Safety Administration (PHMSA), Office of Pipeline Safety (OPS), pursuant to Chapter 601 of 49 United States Code (U.S.C.) reviewed the submission and investigated these conditions. As a result of the investigation, PHMSA issued to Columbia a Warning Letter (Original Notice) on March 15, 2022. PHMSA is issuing this Amended Warning Letter to correct errors in Well numbers that were present in the table below. As a result of the inspection, it is alleged that you have committed a probable violation of the Pipeline Safety Regulations, Title 49, Code of Federal Regulations (CFR). The item inspected and the probable violation is: 1. § 191.25 Filing safety-related condition reports. (a) Each report of a safety-related condition under § 191.23(a)(1) through (9) must be filed (received by the Associate Administrator) in writing within 5 working days (not including Saturday, Sunday, or Federal holidays) after the day a representative of an operator first determines that the condition exists, but not later than 10 working days after the day a representative of an operator discovers the condition. Separate conditions may be described in a single report if they are#

12022018WL_Warning Letter (Amended)_03302022_(21-231686)_text.pdf, page 2CPF 1-2022-018-WL closely related. Reporting methods and report requirements are described in paragraph (c) of this section. Columbia failed to file 14 safety related condition (SRC) reports within the reporting requirements of § 191.25(a). Specifically, Columbia failed to file reports within 5 working days after the day a representative first determined that the conditions existed, but not later than 10 working days after the day a representative of Columbia discovered the conditions. On May 10, 2021, PHMSA received a letter from Columbia reporting the discovery of 14 SRCs in which underground natural gas storage wells were not isolated from the storage horizon within 5 business days or reported to PHMSA within the required 10 days of discovery. The following table is a list of SRCs identified and submitted by Columbia on May 10, 2021. Well Name 7152 Date of Discovery 11/30/2020 Date of Determination Date Well out of service Notification date 11/30/2020 1/11/2021 5/10/2021 7220 1/31/2020 1/31/2020 4/19/2021 5/10/2021 4337 6/8/2020 6/8/2020 4/1/2020 5/10/2021 12430 1/31/2020 1/31/2020 7/15/2020 5/10/2021 4275 5/1/2020 5/1/2020 7/24/2020 5/10/2021 11176 6/8/2020 6/8/2020 4/1/2021 5/10/2021 1194 9/2/2020 9/2/2020 4/8/2021 5/10/2021 10001 6/13/2019 6/13/2019 2/8/2021 5/10/2021 11418 5/1/2020 4/28/2021 11/13/2020 5/10/2021 3762 9/2/2020 1/20/2021 1/26/2021 5/10/2021 10374 10/20/2020 11/6/2020 6/4/2020 5/10/2021 10729 1/31/2020 1/31/2020 4/16/2021 5/10/2021 10817 5/1/2020 5/1/2020 2/6/2020 5/10/2021 548 4/26/2019 1/11/2020 4/1/2020 5/10/2021 Therefore, Columbia failed to report 14 safety related conditions in accordance with the reporting requirements of § 191.25. Under 49 U.S.C. § 60122 and 49 CFR § 190.223, you are subject to a civil penalty not to exceed $225,134 per violation per day the violation persists, up to a maximum of $2,251,334 for a related series of violations. For violation occurring on or after January 11, 2021 and before May 3, 2021, the maximum penalty may not exceed $222,504 per violation per day the violation persists, up to a maximum of $2,225,034 for a related series of violations. For violation occurring on or after July 31, 2019 and before January 11, 2021, the maximum penalty may not exceed $218,647 per violation per day the violation persists, up to a maximum of $2,186,465 for a related series of violations. For violation occurring on or after November 27, 2018 and before July 31, 2019, the maximum penalty may not exceed $213,268 per violation per day, with a maximum penalty not to exceed $2,132,679. For violation occurring on or after November 2, 2015 and before November 12022018WL_Warning Letter (Amended)_03302022_(21-231686)_text Page 2 of 3#

12022018WL_Warning Letter (Amended)_03302022_(21-231686)_text.pdf, page 3CPF 1-2022-018-WL 27, 2018, the maximum penalty may not exceed $209,002 per violation per day, with a maximum penalty not to exceed $2,090,022. We have reviewed the circumstances and supporting documents involved in this case and have decided not to conduct additional enforcement action or penalty assessment proceedings at this time. We advise you to correct the item identified in this letter. Failure to do so will result in Columbia Gas Transmission, LLC being subject to additional enforcement action. No reply to this letter is required. If you choose to reply, in your correspondence please refer to CPF 1-2022-018-WL. Be advised that all material you submit in response to this enforcement action is subject to being made publicly available. If you believe that any portion of your responsive material qualifies for confidential treatment under 5 U.S.C. 552(b), along with the complete original document you must provide a second copy of the document with the portions you believe qualify for confidential treatment redacted and an explanation of why you believe the redacted information qualifies for confidential treatment under 5 U.S.C. 552(b). Sincerely, Robert Burrough Director, Eastern Region, Office of Pipeline Safety Pipeline and Hazardous Materials Safety Administration 12022018WL_Warning Letter (Amended)_03302022_(21-231686)_text Page 3 of 3#

12022018WL_Warning Letter_03152022_(21-231686)_text.pdf, page 1Official PDFWARNING LETTER OVERNIGHT EXPRESS DELIVERY March 15, 2022 Mr. Stanley Chapman Executive Vice President & President US & Mexico Natural Gas Columbia Gas Transmission, LLC 7000 Louisiana Street Houston, Texas 77002 CPF 1-2022-018-WL Dear Mr. Chapman: On May 10, 2021, Columbia Gas Transmission, LLC (Columbia) submitted to PHMSA a letter related to Safety-Related Condition Reports. A representative of the Pipeline and Hazardous Materials Safety Administration (PHMSA), Office of Pipeline Safety (OPS), pursuant to Chapter 601 of 49 United States Code (U.S.C.) reviewed the submission and investigated these conditions. As a result of the inspection, it is alleged that you have committed a probable violation of the Pipeline Safety Regulations, Title 49, Code of Federal Regulations (CFR). The item inspected and the probable violation is: 1. § 191.25 Filing safety-related condition reports. (a) Each report of a safety-related condition under § 191.23(a)(1) through (9) must be filed (received by the Associate Administrator) in writing within 5 working days (not including Saturday, Sunday, or Federal holidays) after the day a representative of an operator first determines that the condition exists, but not later than 10 working days after the day a representative of an operator discovers the condition. Separate conditions may be described in a single report if they are closely related. Reporting methods and report requirements are described in paragraph (c) of this section. Columbia failed to file 13 safety related condition (SRC) reports within the reporting requirements#

12022018WL_Warning Letter_03152022_(21-231686)_text.pdf, page 2CPF 1-2022-018-WL of § 191.25(a). Specifically, Columbia failed to file reports within 5 working days after the day a representative first determined that the conditions existed, but not later than 10 working days after the day a representative of Columbia discovered the conditions. On May 10, 2021, PHMSA received a letter from Columbia reporting the discovery of 13 SRCs in which underground natural gas storage wells were not isolated from the storage horizon within 5 business days or reported to PHMSA within the required 10 days of discovery. The following table is a list of SRCs identified and submitted by Columbia on May 10, 2021. Well Name Date of Discovery Date of Determination Date Well out of service Notification date 7152 11/30/2020 11/30/2020 1/11/2021 5/10/2021 7220 1/31/2020 1/31/2020 4/19/2021 5/10/2021 12430 1/31/2020 1/31/2020 7/15/2020 5/10/2021 11176 6/8/2020 6/8/2020 4/1/2021 5/10/2021 1194 9/2/2020 9/2/2020 4/8/2021 5/10/2021 10001 6/13/2019 6/13/2019 2/8/2021 5/10/2021 11418 5/1/2020 4/28/2021 11/13/2020 5/10/2021 3762 9/2/2020 1/20/2021 1/26/2021 5/10/2021 10374 10/20/2020 11/6/2020 6/4/2020 5/10/2021 10729 1/31/2020 1/31/2020 4/16/2021 5/10/2021 10817 5/1/2020 5/1/2020 2/6/2020 5/10/2021 548 4/26/2019 1/11/2020 4/1/2020 5/10/2021 9409 2/7/2020 2/7/2020 4/1/2020 5/10/2021 Therefore, Columbia failed to report 13 safety related conditions in accordance with the reporting requirements of § 191.25. Under 49 U.S.C. § 60122 and 49 CFR § 190.223, you are subject to a civil penalty not to exceed $225,134 per violation per day the violation persists, up to a maximum of $2,251,334 for a related series of violations. For violation occurring on or after January 11, 2021 and before May 3, 2021, the maximum penalty may not exceed $222,504 per violation per day the violation persists, up to a maximum of $2,225,034 for a related series of violations. For violation occurring on or after July 31, 2019 and before January 11, 2021, the maximum penalty may not exceed $218,647 per violation per day the violation persists, up to a maximum of $2,186,465 for a related series of violations. For violation occurring on or after November 27, 2018 and before July 31, 2019, the maximum penalty may not exceed $213,268 per violation per day, with a maximum penalty not to exceed $2,132,679. For violation occurring on or after November 2, 2015 and before November 27, 2018, the maximum penalty may not exceed $209,002 per violation per day, with a maximum penalty not to exceed $2,090,022. We have reviewed the circumstances and supporting documents involved in this case and have decided not to conduct additional enforcement action or penalty assessment proceedings at this 12022018WL_Warning Letter_03152022_(21-231686)_text Page 2 of 3#

12022018WL_Warning Letter_03152022_(21-231686)_text.pdf, page 3CPF 1-2022-018-WL time. We advise you to correct the item identified in this letter. Failure to do so will result in Columbia Gas Transmission, LLC being subject to additional enforcement action. No reply to this letter is required. If you choose to reply, in your correspondence please refer to CPF 1-2022-018-WL. Be advised that all material you submit in response to this enforcement action is subject to being made publicly available. If you believe that any portion of your responsive material qualifies for confidential treatment under 5 U.S.C. 552(b), along with the complete original document you must provide a second copy of the document with the portions you believe qualify for confidential treatment redacted and an explanation of why you believe the redacted information qualifies for confidential treatment under 5 U.S.C. 552(b). Sincerely, Robert Burrough Director, Eastern Region, Office of Pipeline Safety Pipeline and Hazardous Materials Safety Administration 12022018WL_Warning Letter_03152022_(21-231686)_text Page 3 of 3#