GULF SOUTH PIPELINE COMPANY, LLC — Corrective Action Order

32026020CAO_Corrective Action Order_05162026_(26-372495)_text.pdf, page 1Official PDFMay 16, 2026 VIA EMAIL TO: scott.hallam@bwpipelines.com Scott Hallam President and CEO Gulf South Pipeline Company, LLC 9 Greenway Plaza, Suite 2800 Houston, Texas 77046 CPF 3-2026-020-CAO Dear Mr. Hallam: Enclosed please find a Corrective Action Order (“CAO” or “Order”) issued by the Pipeline and Hazardous Materials Safety Administration (PHMSA), Office of Pipeline Safety (OPS). The CAO requires Gulf South Pipeline Company, LLC (Gulf South) to take certain corrective actions with respect to the pipeline failure that occurred on May 14, 2026, on a 20-inch diameter interstate natural gas transmission line near Choudrant, Louisiana. Service of the CAO by email is effective upon the date of transmission and acknowledgment of receipt as provided under 49 CFR § 190.5. The terms and conditions of this Order are effective upon completion of service. Sincerely, Linda Daugherty Associate Administrator Pipeline and Hazardous Materials Safety Administration Enclosure: CAO cc: AJ McKean, Central Region Director, Office of Pipeline Safety, PHMSA Tim Brown, Manager of Compliance and Assurance, Boardwalk Pipelines, tim.brown@bwpipelines.com Michael Preuit, Manager of Integrity, Boardwalk Pipelines, micheal.preuit@bwpipelines.com#

32026020CAO_Corrective Action Order_05162026_(26-372495)_text.pdf, page 21 DEPARTMENT OF TRANSPORTATION PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION OFFICE OF PIPELINE SAFETY WASHINGTON, D.C. 20590 ____________________________________ In the Matter of ) Gulf South Pipeline Company, LLC, ) CPF No. 3-2026-020-CAO ) ) ) Respondent ) ____________________________________) CORRECTIVE ACTION ORDER Background and Purpose The Pipeline and Hazardous Materials Safety Administration (PHMSA), Office of Pipeline Safety (OPS), is issuing this Corrective Action Order (CAO or Order) pursuant to the authority provided in 49 U.S.C. § 60112. The CAO requires Gulf South Pipeline Company, LLC (Gulf South or Respondent), a subsidiary of Boardwalk Pipelines, to take certain necessary corrective actions to protect the public, property, and the environment from the potential hazards associated with the continued operation of its interstate 266 loop line. The 266 loop line is a 1949 vintage, 20-inch diameter interstate natural gas transmission line. On May 14, 2026, the 266 loop line ruptured near Choudrant, Louisiana (Failure). The Failure resulted in the release of natural gas. Gulf South responded by closing main line block valves and taking approximately 17 miles of pipe out of service. PHMSA inspectors dispatched to the scene of the Failure and observed the excavation and removal of the ruptured pipe. Visual inspection indicated that the rupture originated in the longitudinal seam. Pursuant to 49 U.S.C. § 60117, PHMSA has initiated an investigation of the Failure. The preliminary findings of PHMSA’s ongoing investigation are as follows: ● The 266 loop line is a 20-inch diameter interstate gas transmission line installed prior to the adoption of the Federal safety standards in 49 CFR Part 192. ● The 266 loop line is constructed with pipe manufactured by Youngstown Steel in 1949 with a DC-ERW seam. ● The 266 loop line received a pressure test in 1984 to 1082 psig. ● The 266 loop line has a maximum allowable operating pressure (MAOP) of 828 psig.#

32026020CAO_Corrective Action Order_05162026_(26-372495)_text.pdf, page 32 ● Gulf South conducted in-line inspection of the 266 loop line using magnetic flux leakage (MFL) tools in 2005, 2011, 2018, and 2025. ● On May 14, 2026, at 10:27 PM, Gulf South supervisory control and data acquisition (SCADA) system received a low-low pressure alarm. ● The low-low pressure alarm indicated that the 266 loop line had ruptured near Choudrant, Louisiana. ● The operating pressure of the 266 loop line at the time of the rupture was 760 psig. ● The portion of the 266 loop line that ruptured is in a Class 1 location. ● The rupture resulted in the release of natural gas. ● The rupture did not result in any injuries or fatalities. ● Gulf South technicians closed the main line block valves on the 266 loop line after the rupture, taking approximately 17 miles of pipe out of service. ● On May 15, 2026, PHMSA inspectors arrived at the scene to witness the excavation and removal of the ruptured pipe. ● PHMSA inspectors observed that the rupture originated in the longitudinal seam of the pipe. ● Gulf South has sent the ruptured pipe to a third-party laboratory for metallurgical testing. ● Gulf South is in the process of repairing the 266 loop line. Determination of Necessity for Corrective Action Order and Right to Hearing Section 60112 of title 49, United States Code, authorizes PHMSA to determine that a pipeline facility is or would be hazardous to life, property, or the environment and if there is a likelihood of serious harm, to expeditiously order the operator of the facility to take necessary corrective action, including suspended or restricted use of the facility, physical inspection, testing, repair, replacement, or other appropriate action. An order issued expeditiously must provide an opportunity for a hearing as soon as practicable after the order is issued. In deciding whether to issue an order, PHMSA must consider the following, if relevant: (1) the characteristics of the pipe and other equipment used in the pipeline facility, including the age, manufacture, physical properties, and method of manufacturing, constructing, or assembling the equipment; (2) the nature of the material the pipeline facility transports, the corrosive and deteriorative qualities of the material, the sequence in which the material is transported, and the pressure required for transporting the material; (3) the aspects of the area in which the pipeline facility is located, including climatic and geologic conditions and soil characteristics; (4) the proximity of the area in which the facility is located to environmentally sensitive areas; (5) the population density and population and growth patterns of the area in which the pipeline facility is located; (6) any recommendation of the National Transportation Safety Board made under another law; and (7) any other factors PHMSA may consider as appropriate. The preliminary findings of fact indicate that the 266 loop line is constructed with vintage pipe of a seam type that is known to be susceptible to potential integrity issues, i.e., DC-ERW pipe#

32026020CAO_Corrective Action Order_05162026_(26-372495)_text.pdf, page 43 manufactured in 1949 by Youngtown Steel; that this vintage seam type pipe ruptured due to a longitudinal seam defect that Gulf South failed to detect and remediate following multiple MFL ILI tool runs; and that the rupture resulted in the release of natural gas, creating potential impacts to life, property and the environment. For these reasons, and considering the nature of the Failure, the possibility that the cause of the Failure may be present elsewhere on the 266 loop line, the hazardous nature of the material transported (natural gas), and the existing and potential impacts to life, property, and the environment, it is hereby determined that continued operation of the Affected Segment of the 266 loop line, as defined below, without corrective measures is or would be hazardous to life, property, or the environment, and that failure to issue this Order expeditiously would result in the likelihood of serious harm. Accordingly, this Order mandating immediate corrective action is issued expeditiously without prior notice and opportunity for a hearing. The terms and conditions of this Order are effective upon completion of service. Within 10 days of receipt of this Order, Respondent may request a hearing, to be held as soon as practicable, by notifying the Associate Administrator for Pipeline Safety in writing, with a copy to the Director, PHMSA, OPS Central Region. If a hearing is requested, it will be held in accordance with 49 CFR § 190.211. After receiving and analyzing additional data in the course of this investigation, PHMSA may identify other corrective measures that need to be taken. Gulf South will be notified of any additional measures required and, if appropriate, PHMSA will consider a further amended order. To the extent consistent with safety, Gulf South will be afforded notice and an opportunity for a hearing prior to the imposition of any additional corrective measures. Corrective Measures Definitions Affected Segment – The “Affected Segment” means the pipe and facilities from the upstream compressor station (Halls Summit) to the West Monroe Junction (end of line) where the Failure occurred. Director – The “Director” means the Director, PHMSA, OPS Central Region. Failure – The “Failure” means the rupture and resulting release of natural gas that occurred on the 266 loop line near Choudrant, Louisiana, on May 14, 2026. Isolated Segment – The “Isolated Segment” means the 17 miles of pipeline taken out of service following the Failure (station 2934+98 to station 3845+22) on Index 266-L. 1. Shut Down. Gulf South must not operate the Isolated Segment until authorized to do so by the Director.#

32026020CAO_Corrective Action Order_05162026_(26-372495)_text.pdf, page 54 2. Operating Pressure Restriction. Gulf South must reduce and maintain a twenty percent (20%) pressure reduction in the actual operating pressure along the entire length of the Affected Segment such that the operating pressure along the Affected Segment will not exceed eighty percent (80%) of the actual operating pressure in effect immediately prior to the Failure. a. This pressure restriction is to remain in effect until written approval to increase the pressure or return the pipeline to its pre-failure operating pressure is obtained from the Director. b. Within 10 days of receipt of this Order, Gulf South must provide the Director the actual operating pressures of each pump/compressor station and each main line pressure regulating station on the Affected Segment at the time of failure and the reduced pressure restriction set-points at these same locations. c. This pressure restriction requires any relevant remote or local alarm limits, software programming set-points or control points, and mechanical over-pressure devices to be adjusted accordingly. d. When determining the pressure restriction set-points, Gulf South must take into account any in-line inspection (ILI) features or anomalies present in the Affected Segment to provide for continued safe operation while further corrective actions are completed. e. Gulf South must review the pressure restriction monthly by analyzing the operating pressure data. Gulf South must take into account any in-line inspection (ILI) features or anomalies present in the Affected Segment and immediately reduce the operating pressure to maintain the safe operations of the Affected Segment, if warranted by the monthly review. Gulf South must submit the results of the monthly review to the Director. The results must include, at a minimum, the current discharge set-points (including any additional pressure reductions), and any pressure exceedance at discharge set-points. 3. Restart Plan. Prior to resuming operation of the Isolated Segment, Gulf South must develop and submit a written Restart Plan to the Director for prior approval. a. The Director may approve the Restart Plan incrementally without approving the entire plan, but the Isolated Segment cannot resume operation until the Restart Plan is approved in its entirety. b. Once approved by the Director, the Restart Plan will be incorporated by reference into this Order. c. The Restart Plan must provide for adequate patrolling of the Isolated Segment during the restart process and must include incremental pressure increases during start up, with each increment to be held for at least 2 hours. d. The Restart Plan must specify a day-light restart and include advanced communications with local emergency response officials. e. The Restart Plan must provide for a review of the Isolated Segment for conditions similar to those of the Failure including a review of construction, operating and maintenance (O&M), and integrity management records such as in-line inspection#

32026020CAO_Corrective Action Order_05162026_(26-372495)_text.pdf, page 65 (ILI) results, hydrostatic tests, root cause failure analysis of prior failures, aerial and ground patrols, corrosion, cathodic protection, excavations, and pipe replacements. Gulf South must address any findings that require remedial measures to be implemented prior to restart. f. The Restart Plan must also include documentation of the completion of all mandated actions, and a management of change plan to ensure that all procedural modifications are incorporated into Gulf South’s operations and maintenance procedures manual. 4. Return to Service. After the Director approves the Restart Plan, Gulf South may return the Isolated Segment to service but the operating pressure must not exceed eighty percent (80%) of the actual operating pressure in effect immediately prior to the Failure on May 14, 2026, in accordance with Item 2 above. 5. Removal of Pressure Restriction. The Director may allow the removal or modification of the pressure restriction upon a written request from Gulf South demonstrating that restoring the pipeline to its pre-failure operating pressure is justified based on a reliable engineering analysis showing that the pressure increase is safe considering all known defects, anomalies, and operating parameters of the pipeline. 6. Temporary Modification of Pressure Restrictions. The Director may allow the temporary removal or modification of the pressure restrictions upon a written request from Gulf South demonstrating that temporary mitigative and preventive measures are implemented prior to and during the temporary removal or modification of the pressure restriction. The Director's determination will be based on the Failure cause and provision of evidence that preventative and mitigative actions taken by the operator provide for the safe operation of the Affected Segment during the temporary removal or modification of the pressure restriction. Appeals to determinations of the Director in this regard will be decided by the Associate Administrator for Pipeline Safety. 7. Mechanical and Metallurgical Testing. Within 45 days of receipt of this Order, Gulf South must complete mechanical and metallurgical testing and failure analysis of the failed pipe, including an analysis of soil samples and any foreign materials. Gulf South must submit the completed final report of this testing and analysis to the Director for review and approval. Gulf South must ensure that all reports, whether draft or final, are made available in their entirety to the Director at the same time they are made available to Gulf South. Mechanical and metallurgical testing must be conducted by an independent third-party approved by the Director prior to commencing testing and must document the decision- making process and all factors contributing to the failure. Respondent must complete the testing and analysis as follows: a. Document the chain-of-custody when handling and transporting the failed pipe section and other evidence from the Failure site. b. Within 10 days of receipt of this Order, develop and submit the testing protocol and the proposed testing laboratory to the Director for prior approval. c. Prior to beginning the mechanical and metallurgical testing, provide the Director with the scheduled date, time, and location of the testing to allow for an OPS representative to witness the testing.#

32026020CAO_Corrective Action Order_05162026_(26-372495)_text.pdf, page 76 d. Ensure the testing laboratory distributes all reports whether draft or final in their entirety to the Director at the same time they are made available to Gulf South. 8. Root Cause Failure Analysis. Within 90 days following receipt of this Order, Gulf South must complete a root cause failure analysis (RCFA) and submit a final report of this RCFA to the Director for review and approval. No later than 30 days following receipt of this Order, Gulf South must provide the scope and protocol of the RCFA to the Director for review and approval. The RCFA must be conducted by an independent third-party approved by the Director prior to commencing the analysis, and must document the decision-making process and all factors contributing to the failure. Gulf South must direct the third-party to engage in once-a-week calls with PHMSA to provide updates as to the progress of the RCFA. These calls shall be done virtually and continue until the RCFA has been submitted to the Director. Gulf South must ensure that all reports, whether draft or final, are made available in their entirety to the Director at the same time they are made available to Gulf South. The final report must include findings, and any lessons learned and whether the findings and any lessons learned are applicable to other locations within Gulf South’s pipeline system. 9. Remedial Work Plan (RWP). a. Within 60 days of approval of the RCFA required above, Gulf South must submit a Remedial Work Plan (RWP) to the Director for approval. b. The Director may approve the RWP incrementally without approving the entire RWP. c. Once approved by the Director, the RWP will be incorporated by reference into this Order. d. The RWP must specify the tests, inspections, assessments, evaluations, and remedial measures Gulf South will use to verify the integrity of the Affected Segment. It must address all known or suspected factors and causes of the Failure. Guld South should consider both the risk of another failure and the consequence of another failure to develop a prioritized schedule for RWP related work along the Affected Segment. e. The RWP must include a procedure or process to: i. Identify pipe within Gulf South’s systems (OPID 31728) with characteristics similar to the contributing factors identified for the Failure. ii. Gather all data necessary to review the failure history (in service and pressure test failures) of pipe within Gulf South’s systems (OPID 31728) and to prepare a written report containing all the available information such as the locations, dates, and causes of leaks and failures. iii. Integrate the results of the metallurgical testing, root cause failure analysis, and other corrective actions required by this Order with all relevant pre- existing operational and assessment data for pipe within Gulf South’s systems (OPID 31728). Pre-existing operational data includes, but is not limited to, construction, operations, maintenance, testing, repairs, prior metallurgical analyses, and any third-party consultation information. Pre-#

32026020CAO_Corrective Action Order_05162026_(26-372495)_text.pdf, page 87 existing assessment data includes, but is not limited to, ILI tool runs, hydrostatic pressure testing, direct assessments, close interval surveys, and DCVG/ACVG surveys. iv. Determine if conditions similar to those contributing to the Failure are likely to exist elsewhere on pipe within Gulf South’s systems (OPID 31728). Conduct additional field tests, inspections, assessments, and/or evaluations to determine whether, and to what extent, the conditions associated with the Failure and other failures from the failure history (see 9(e)(ii) above) or any other integrity threats are present elsewhere on the pipe within Gulf South’s systems (OPID 31728). At a minimum, this process must consider all failure causes and specify the following: 1) Inline inspection (ILI) tools that are technically appropriate for assessing the pipeline system based on the cause of the Failure and that can reliably detect and identify anomalies, 2) Hydrostatic pressure testing, 3) Corrosion control methods including cathodic protection and coating evaluations, close-interval surveys, evaluation of stray current, and stress corrosion cracking and selective seam corrosion surveys, if applicable, 4) Other tests, inspections, assessments, and evaluations appropriate for the Failure causes. Note: Gulf South may use the results of previous tests, inspections, assessments, and evaluations if approved by the Director, provided the results of the tests, inspections, assessments, and evaluations are analyzed with regard to the factors known or suspected to have caused the Failure. v. Describe the inspection and repair criteria Gulf South will use to prioritize, excavate, evaluate, and repair anomalies, imperfections, and other identified integrity threats, including those related to processes applied per 9(e)(iv) above. Include a description of how any defects will be graded and a schedule for repairs or replacement. vi. Based on the known history and condition of the pipe within Gulf South’s systems (OPID 31728), describe the methods Gulf South will use to repair, replace, or take other corrective measures to remediate the conditions associated with the Failure and to address other known integrity threats along the pipe within Gulf South’s systems (OPID 31728). The repair, replacement, or other corrective measures must meet the criteria specified in 9(e)(v) above. vii. Incorporate findings and lessons learned in response to the Failure in all related programs and procedures to ensure the ongoing safe operation of the pipe within Gulf South’s systems (OPID 31728) considering the results of the analyses, inspections, and evaluations resulting from actions taken in response to this Order.#

32026020CAO_Corrective Action Order_05162026_(26-372495)_text.pdf, page 98 f. Include a proposed schedule for completion of the RWP. g. Gulf South must revise the RWP as necessary to incorporate new information obtained during the failure investigation and remedial activities, to incorporate the results of actions undertaken pursuant to this Order, and to incorporate modifications required by the Director. Gulf South must submit any plan revisions to the Director for prior approval. The Director may approve plan revisions incrementally. Any and all revisions to the RWP after it has been approved and incorporated by reference into this Order will be fully described and documented in the CAO Documentation Report (CDR). h. Gulf South must implement the RWP as it is approved by the Director, including any revisions to the plan. 10. CAO Documentation Report (CDR). Gulf South must create and revise, as necessary, a CAO Documentation Report (CDR). When Gulf South has concluded all the items in this Order it will submit the final CDR in its entirety to the Director. This will allow the Director to complete a thorough review of all actions taken by Gulf South with regards to this Order prior to approving the closure of this Order. The intent is for the CDR to summarize all activities and documentation associated with this Order in one document. a. The Director may approve the CDR incrementally without approving the entire CDR. b. Once approved by the Director, the CDR will be incorporated by reference into this Order. c. The CDR must include but not be limited to: i. Table of Contents; ii. Summary of the pipeline Failure, and the response activities; iii. Summary of pipe data and properties and all prior assessments of the Affected Segment; iv. Summary of all tests, inspections, assessments, evaluations, and analysis required by the Order; v. Summary of the Mechanical and Metallurgical Testing as required by the Order; vi. Summary of the RCFA with all root causes as required by the Order; vii. Documentation of all actions taken by Gulf South to implement the RWP, the results of those actions, and the inspection and repair criteria used; viii. Documentation of any revisions to the RWP including those necessary to incorporate the results of actions undertaken pursuant to this Order and whenever necessary to incorporate new information obtained during the failure investigation and remedial activities; ix. Lessons learned while completing this Order;#

32026020CAO_Corrective Action Order_05162026_(26-372495)_text.pdf, page 109 x. A path forward describing specific actions Gulf South will take on its entire pipeline system as a result of the lessons learned from work on this Order; and xi. Appendices (if required). 11. Reporting. Gulf South must submit quarterly reports to the Director that: (1) include all available data and results of the testing and evaluations required by this Order; and (2) describe the progress of the repairs or other remedial actions being undertaken. The first quarterly report is due on August 14, 2026, covering the period through the date the quarterly report is submitted. The Director may change the interval for the submission of these reports. 12. Documentation of the Costs. It is requested that Respondent maintain documentation of the costs associated with implementation of this CAO. Include in each quarterly report submitted the to-date total costs associated with: (1) preparation and revision of procedures, studies, and analyses; (2) physical changes to pipeline infrastructure, including repairs, replacements, and other modifications; and (3) environmental remediation, if applicable. Administrative Actions 13. Approvals. With respect to each submission under this Order that requires the approval of the Director, the Director may: (a) approve, in whole or part, the submission; (b) approve the submission on specified conditions; (c) modify the submission to cure any deficiencies; (d) disapprove in whole or in part, the submission, directing that Respondent modify the submission, or (e) any combination of the above. In the event of approval, approval upon conditions, or modification by the Director, Respondent shall proceed to take all action required by the submission as approved or modified by the Director. If the Director disapproves all or any portion of the submission, Respondent must correct all deficiencies within the time specified by the Director and resubmit it for approval. 14. Extensions of Time. The Director may grant an extension of time for compliance with any of the terms of this Order upon a written request timely submitted demonstrating good cause for an extension. Be advised that all material submitted 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). In your correspondence on this matter, please refer to “CPF No. 3-2026-020-CAO” and for each document you submit, please provide a copy in electronic format whenever possible. The actions required by this Order are in addition to and do not waive any requirements that apply to Respondent’s pipeline system under 49 CFR Parts 190 through 199, under any other order issued to Respondent under authority of 49 U.S.C. Chapter 601, or under any other provision of federal or state law.#

32026020CAO_Corrective Action Order_05162026_(26-372495)_text.pdf, page 1110 Respondent may appeal any decision of the Director to the Associate Administrator for Pipeline Safety. Decisions of the Associate Administrator shall be final. Failure to comply with this Order may result in the assessment of civil penalties and in referral to the Attorney General for appropriate relief in United States District Court pursuant to 49 U.S.C. § 60120. The terms and conditions of this Order are effective upon service in accordance with 49 CFR § 190.5. __________________________ _______________________ Linda Daugherty Date Issued Acting Associate Administrator for Pipeline Safety#