Rockies Express Pipeline, LLC — Pipeline Special Permit

2025-0455 - Final Conditions - REX, page 1Official PDFU.S. DEPARTMENT OF TRANSPORTATION PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION SPECIAL PERMIT – Alternative MAOP Special Permit Information: Docket Number: PHMSA-2025-0455 Requested By: Rockies Express Pipeline, LLC Operator ID#: 32163 Original Date Requested: July 18, 2025 Original Issuance Date: May 27, 2026 Effective Date: May 27, 2026 Code Sections: 49 CFR § 192.620(b)(2), (b)(4), (b)(7), (c)(1), (c)(2), (c)(3), (c)(4), (c)(5), (c)(7), (d)(6), (d)(7)(i), (d)(7)(ii), (d)(7)(iii), (d)(9), (d)(11)(ii)(a), (d)(4)(v) and (d)(7)(iv)(B) Grant of Special Permit: By this order, the Pipeline and Hazardous Materials Safety Administration (PHMSA), Office of Pipeline Safety (OPS)1 grants this special permit to Rockies Express Pipeline, L.L.C. (REX). 2 This special permit waives certain design, construction, and certification requirements in 49 Code of Federal Regulations (CFR) § 192.620, Alternative maximum allowable operating pressure for certain steel pipelines, that would otherwise apply to the 2,886 gas transmission special permit segments in the REX pipeline. These special permit segments currently operate at a maximum allowable operating pressure (MAOP) of 1,480 pounds per square inch gauge (psig) pursuant to waivers granted by PHMSA in two previous orders.3 The waivers—originally issued prior to the adoption of the alternative maximum allowable operating pressure (AMAOP) requirements in 49 CFR § 192.620—authorized the operation of special permit segments at an MAOP resulting in a hoop stress of up to 80 percent of the specified minimum yield strength (SMYS). 1 Throughout this special permit, the use of “PHMSA” or “PHMSA OPS” means the U.S. Department of Transportation’s Pipeline and Hazardous Materials Safety Administration Office of Pipeline Safety. 2 Rockies Express Pipeline, L.L.C. (REX) is owned by Tallgrass Energy, L.P. 3 Pursuant to PHMSA dockets PHMSA-2006-23998 and PHMSA-2022-0044. Special Permit – Alternative MAOP Acceptance Page 1 of 4#

2025-0455 - Final Conditions - REX, page 2Section 192.620 stipulates that operators must adhere to specific design, pressure testing, class location, and operations and maintenance (O&M) requirements to maintain an AMAOP. This special permit authorizes REX to continue operating the special permit segments as an AMAOP pipeline under the conditions identified herein for Class 1 locations. It also grants permission to operate similarly in Class 2 locations that originally were designed and constructed for a hoop stress of up to 80 percent SMYS under the waiver granted in Docket No. PHMSA-2006-23998. I. Purpose and Need The special permit would allow REX to operate mainline segments—originally designed and constructed per Docket No. PHMSA-2006-23998—as an AMAOP pipeline in accordance with 49 CFR §192.620 by waiving the following paragraphs of 49 CFR § 192.620: (b)(2), design requirements; (b)(4), construction requirements; (b)(7), nondestructive examination; (c)(1), notification; (c)(2), certification; (c)(3), certification delivery; (c)(4), strength testing; (c)(5), operations requirements; (c)(7), records retention; (d)(6), interference–external corrosion; (d)(7)(i), (d)(7)(ii), (d)(7)(iii), corrosion control indirect assessment; (d)(9), integrity baseline assessment; and (d)(11)(ii)(A), dent defect repair; and by implementing 49 CFR § 192.620(d)(4)(v), damage prevention within 1 year; and (d)(7)(iv)(B), pipe-to-soil test stations in high consequence areas within 1 year. The 2006 waiver had similar requirements to the proposed sections of 49 CFR § 192.620 to be waived by this special permit but varied slightly as shown in Attachment E of Docket No. PHMSA-2025-0455. Docket No. PHMSA-2006-23998 allowed REX to operate certain segments of the REX pipeline at hoop stresses up to 80 percent of SMYS in Class 1 locations and at an MAOP of 1,480 psig. The 46 waiver conditions included in Docket No. PHMSA-2006-23998 were a precursor to— and provided an equivalent level of safety to—the design, construction, operations, maintenance, and integrity management requirements later adopted in 49 CFR § 192.620. Docket No. PHMSA-2022-0044 allowed REX to waive compliance with 49 CFR § 192.611 for Class 1 to Class 2 location changes for 20 specific miles, totaling approximately 4.25 non- contiguous miles of the REX pipeline originally operated under the 2006 waiver. Docket No. PHMSA-2022-0044 will be superseded and replaced by this special permit based on the class change allowance granted by 49 CFR §§ 192.620(c)(8) and 192.611(a), which allow the REX pipeline segments originally designed to operate at 80 percent of SMYS in Class 1 locations to be upgraded one class. This special permit will allow REX to continue safely operating mainline segments at hoop stresses up to 80 percent of SMYS pursuant to 49 CFR § 192.620 while waiving certain design, construction, and certification requirements. This special permit will create a unified and consistent approach for managing the REX pipeline. II. Special Permit Segments and Inspection Areas The request submitted by the operator and supporting documents can be viewed under Docket No. PHMSA-2025-0455 in the Federal Docket Management System located at www.regulations.gov. This special permit pertains to the 2,886 special permit segments and corresponding special permit inspection areas identified in Attachment A. The special permit Special Permit – Alternative MAOP Acceptance Page 2 of 4#

2025-0455 - Final Conditions - REX, page 3covers approximately 1,162 non-contiguous miles of interstate pipeline, extending from the Cheyenne Compressor Station (latitude, longitude of approximately 40.947022, -104.796757) in Weld County, Colorado, to the Clarington Hub (latitude, longitude of approximately 39.831828, -80.877256) in Monroe County, Ohio. The special permit segments contain 42-inch steel mainline piping, operating at 1,480 psig with hoop stresses of up to 80 percent SMYS, installed under the 2006 special permit, PHMSA-2006-23998. The REX pipeline segments that were originally designed to operate at hoop stresses of up to 72 percent SMYS are not subject to the special permit. Maps of the REX pipeline are available at www.npms.phmsa.dot.gov. To search for maps of the REX pipeline, select Use Public Map Viewer tool, search by State and county, and use the Query Tool to search by Operator ID to find REX pipelines operated in each county. III. Conditions PHMSA grants this special permit subject to REX’s compliance with the following conditions. These conditions must be implemented in addition to all applicable requirements of the Federal pipeline safety regulations, except for the provisions in 49 CFR § 192.620 that are specifically waived below: 1) MAOP: REX will continue to operate at current MAOP of up to 1,480 psig. 2) Notifications: REX must make all notifications required by 49 CFR § 192.620, except to the extent compliance is waived by Condition 5 of this special permit, to PHMSA and State agents after the permit is granted. 3) Procedures: REX must implement, develop, and modify all relevant procedural changes necessary within 90 days of the granting of this special permit. 4 4) Record Requirements: REX must maintain records demonstrating compliance with 49 CFR § 192.620, except to the extent compliance is waived by Condition 5 of this special permit, after the date of the issuance of the special permit. 5) Operations and Maintenance: REX must operate the special permit segments as an AMAOP pipeline in compliance with the applicable safety standards in 49 CFR § 192.620, with a waiver of the following design, construction, and certification requirements of 49 CFR § 192.620 going forth from the date of this permit: a. 49 CFR § 192.620(b)(2), (b)(4), (b)(7), (c)(1), (c)(2), (c)(3), (c)(4), (c)(5), (c)(7), (d)(6), (d)(7)(i), (d)(7)(ii), (d)(7)(iii), (d)(9), (d)(11)(ii)(a), and b. 49 CFR § 192.620(d)(4)(v) and (d)(7)(iv)(B) to the extent they require 4 REX must provide the Director, PHMSA Western Region, with all information and documentation specified in this special permit, including when notification is required to PHMSA. If the specified PHMSA Region assignment changes, REX will be notified to which Region it should direct its correspondence. Special Permit – Alternative MAOP Acceptance Page 3 of 4#

2025-0455 - Final Conditions - REX, page 4immediate implementation. Implementation shall be extended to 1 year of the issuance of the special permit. IV. Limitations This special permit is subject to the limitations set forth in 49 CFR § 190.341, as well as the following limitations: 1. PHMSA has the sole authority to make all determinations on whether the operator has complied with the specified conditions of this special permit. Failure to comply with any condition of this special permit may result in revocation of the special permit. 2. Any procedures, plans, and associated schedules for the special permit segments are automatically incorporated into this special permit and are enforceable in the same manner. 4. As provided in 49 CFR § 190.341, PHMSA may issue an enforcement action for failure to comply with this special permit. The terms and conditions of any order issued by PHMSA applicable to a pipeline facility covered by this special permit will take precedence over the terms of this special permit. 5. If the operator sells, merges, transfers, or otherwise disposes of all or part of the assets known as the 42-inch diameter REX pipeline, extending from the Cheyenne Compressor Station in Weld County, Colorado, to the Clarington Hub in Monroe County, Ohio, the operator must provide written notice of the change within 30 days of the consummation date. 6. PHMSA grants this special permit for the operational life of the REX pipeline. 7. PHMSA reserves the right to revoke, suspend, or modify the special permit if a material change occurs in conditions or circumstances underlying the permit. AUTHORITY: 49 U.S. Code 60118(c)(1) and 49 CFR § 1.97. Issued in Washington, D.C., on May 27, 2026. Linda Daugherty Acting Associate Administrator for Pipeline Safety Special Permit – Alternative MAOP Acceptance Page 4 of 4#

2025-0455 - Final Letter of Determination - REX, page 1Official PDFVia E-Mail May 27, 2026 Crystal Heter Chief Operating Officer Tallgrass Energy, L.P. 370 Van Gordon Street Lakewood, CO 80228 Re: Docket No. PHMSA-2025-0455 Dear Ms. Heter: On July 18, 2025, Rockies Express Pipeline, LLC (REX), an entity owned by Tallgrass Energy, L.P., applied to the Pipeline and Hazardous Materials Safety Administration (PHMSA) for a special permit pursuant to 49 Code of Federal Regulations (CFR) § 190.341. In its application, REX asked PHMSA to waive certain requirements in the Federal pipeline safety regulations in 49 CFR Part 192 to allow the REX pipeline to continue to operate mainline segments, originally designed and constructed in accordance with special permit Docket No. PHMSA-2006-23998 as an alternative maximum allowable operating pressure (AMAOP) pipeline in compliance with 49 CFR § 192.620. REX proposed implementing enhanced integrity management practices to provide an equivalent or superior level of safety if PHMSA granted the application. PHMSA has reviewed the public comments and other information in the record and is issuing the enclosed special permit to REX. The special permit waives the requirements in 49 CFR §§ 192.620(b)(2), (b)(4), (b)(7), (c)(1), (c)(2), (c)(3), (c)(4), (c)(5),(c)(7), (d)(6), (d)(7)(i), (d)(7)(ii), (d)(7)(iii), (d)(9), (d)(11)(ii)(a), (d)(4)(v), and (d)(7)(iv)(B) for the REX gas transmission pipeline special permit segments and requires REX to comply with conditions and limitations designed to maintain an equivalent level of pipeline safety. This and other pertinent documents can be reviewed in Docket No. PHMSA-2025-0455 in the Federal Docket Management System at www.regulations.gov. 1 1 https://www.regulations.gov/docket/PHMSA-2025-0455 Special Permit: PHMSA-2025-0455 Letter of Decision – AMAOP Page 1 of 2#

2025-0455 - Final Letter of Determination - REX, page 2Please be advised that the special permit is subject to the requirements in 49 CFR § 190.341(j). If REX does not implement the special permit conditions, REX must notify PHMSA within 60 days and comply with the entirety of 49 CFR § 192.620 within 18 months of the date of this letter. My staff would be pleased to discuss this special permit or any other regulatory matter with you. For technical matter, please contact Max Kieba, Director, Engineering and Research Division, by e-mail at pipelinespecialpermits@dot.gov. For compliance matters specific to this special permit, please contact Dustin Hubbard, Director, Western Region, by e-mail at dustin.hubbard@dot.gov. Sincerely, Linda Daugherty Acting Associate Administrator for Pipeline Safety Enclosure: Special Permit – PHMSA-2025-0455 Special Permit: PHMSA-2025-0455 Letter of Decision – AMAOP Page 2 of 2#

Special Permit Technical Correction, page 1Official PDFJuly 21, 2026 Crystal Heter President and Chief Executive Officer Tallgrass Energy, L.P. 370 Van Gordon Street Lakewood, CO 80228 Re: Docket No. PHMSA-2025-0455; Technical Correction Dear Ms. Heter: On May 27, 2026, the Pipeline and Hazardous Materials Safety Administration (PHMSA) issued to Rockies Express Pipeline, LLC (REX), an entity owned by Tallgrass Energy, L.P., a special permit pursuant to 49 Code of Federal Regulations (CFR) § 190.341. The special permit waives certain requirements in 49 CFR § 192.620 for the REX gas transmission pipeline special permit segments and requires REX to comply with conditions and limitations designed to maintain an equivalent level of pipeline safety. This and other pertinent documents can be reviewed in Docket No. PHMSA-2025-0455 in the Federal Docket Management System at www.regulations.gov. 1 This letter serves to inform you of a technical correction to the special permit. The special permit, on page 2, refers to “20 specific miles, totaling approximately 4.25 non-contiguous miles of the REX pipeline.” This clause should properly read as “20 specific segments, totaling approximately 4.25 non-contiguous miles of the REX pipeline.” This correction is consistent with the draft special permit as it was issued for public notice. No revised permit is forthcoming, and the original permit remains in effect. Sincerely, Max Kieba Director, Engineering and Research, Office of Pipeline Safety 1 https://www.regulations.gov/docket/PHMSA-2025-0455 Special Permit: PHMSA-2025-0455 Letter of Decision – AMAOP Page 1 of 1#

2025-0455 - Special Permit Analysis and Findings - REX, page 1Official PDFU.S. DEPARTMENT OF TRANSPORTATION PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION Special Permit Analysis and Findings Alternative MAOP Special Permit Information: Docket Number: PHMSA-2025-0455 Requested By: Rockies Express Pipeline, LLC Operator ID#: 32163 Original Date Requested: July 18, 2025 Original Issuance Date: May 27, 2026 Code Sections: 49 CFR §192.620(b)(2), (b)(4), (b)(7), (c)(1), (c)(2), (c)(3), (c)(4), (c)(5), (c)(7), (d)(6), (d)(7)(i), (d)(7)(ii), (d)(7)(iii), (d)(9), (d)(11)(ii)(a), (d)(4)(v) and (d)(7)(iv)(B) Purpose: The Pipeline and Hazardous Materials Safety Administration (PHMSA), Office of Pipeline Safety (OPS)1 provides this information to describe the facts of the subject special permit application submitted by Rockies Express Pipeline, LLC (REX), 2 to discuss any relevant public comments received with respect to the application, to present the engineering and safety analysis of the special permit application, and to make findings justifying the requested special permit being granted. Pipeline System Affected: On July 18, 2025, REX applied for a special permit that would, in conjunction with enhanced integrity management (IM) practices, waive 49 Code of Federal Regulations (CFR) § 192.620(b)(2), (b)(4), (b)(7), (c)(1), (c)(2), (c)(3), (c)(4), (c)(5), (c)(7), (d)(6), (d)(7)(i), (d)(7)(ii), (d)(7)(iii), (d)(9), (d)(11)(ii)(a), (d)(4)(v), and (d)(7)(iv)(B) for approximately 1,162 non-contiguous miles of the 1 Throughout this special permit, the use of “PHMSA” or “PHMSA OPS” means the U.S. Department of Transportation’s Pipeline and Hazardous Materials Safety Administration Office of Pipeline Safety. 2 Rockies Express Pipeline, L.L.C. (REX) is owned by Tallgrass Energy. PHMSA-2025-0455 – Rockies Express Pipeline, LLC Special Permit Analysis and Findings Page 1 of 5#

2025-0455 - Special Permit Analysis and Findings - REX, page 242-inch diameter natural gas transmission REX pipeline from the Cheyenne Compressor Station in Weld County, Colorado, to the Clarington Hub in Monroe County, Ohio. Special Permit Request: REX requested that PHMSA allow REX to continue to operate mainline segments, originally designed and constructed per special permit Docket No. 2006-23998, as an alternative maximum allowable operating pressure (AMAOP) pipeline prior to the adoption of the AMAOP requirements in 49 CFR § 192.620. This special permit waives the following paragraphs of 49 CFR § 192.620: (b)(2), design requirements; (b)(4), construction requirements; (b)(7), nondestructive examination; (c)(1), notification; (c)(2), certification; (c)(3), certification delivery; (c)(4), strength testing; (c)(5), operations requirements; (c)(7), records retention; (d)(6), interference – external corrosion; (d)(7)(i), (d)(7)(ii), (d)(7)(iii), corrosion control indirect assessment; (d)(9), integrity baseline assessment; and (d)(11)(ii)(A), dent defect repair; and implements 49 CFR § 192.620(d)(4)(v), damage prevention; and (d)(7)(iv)(B), pipe-to-soil test stations in high consequence areas within 1 year. This special permit supersedes the 2006 waiver as well as Docket No. PHMSA-2022-0044, which allowed REX to waive compliance with 49 CFR § 192.611 for Class 1 to Class 2 location changes for 20 specific segments, totaling approximately 4.25 non-contiguous miles of the REX pipeline originally operated under the 2006 waiver. Pipe descriptions and specifications for the 2,886 special permit segments are detailed in Attachment A in Docket No. PHMSA-2025-0455. Public Notice: On February 9, 2026, PHMSA posted a notice of this special permit request in the Federal Register (91 FR 5803) with a closing date of March 11, 2026. The special permit application letter, Federal Register notice, environmental assessment, and all other pertinent documents are available for review in Docket No. PHMSA-2025-0455 in the Federal Docket Management System located at www.regulations.gov. PHMSA reviewed all public comments received for Docket No. PHMSA-2025-0455 through March 11, 2026. PHMSA received three public comments concerning this special permit request that are addressed below in the public comment summary. On March 20, 2026, PHMSA also received a supplemental letter from REX regarding submitted public comments, which is included in the docket as Attachment B. Specific citations from the Federal pipeline safety regulations 49 CFR Part 190 and Part 192 are referenced throughout PHMSA’s responses to the public comments and are accessible online at eCFR: 49 CFR Chapter I Subchapter D – Pipeline Safety. 3 Summary of Public Comments: PHMSA received a total of three public comments—from the Pipeline Safety Trust (PST), the Environmental Defense Fund (EDF), and one anonymous source. The anonymous source comment was not relevant to the special permit request. Tallgrass also submitted a comment to PHMSA directly, which will be posted to the docket upon publication of the permit. 3 https://www.ecfr.gov/current/title-49/subtitle-B/chapter-I/subchapter-D PHMSA-2025-0455 – Rockies Express Pipeline, LLC Special Permit Analysis and Findings Page 2 of 5#

2025-0455 - Special Permit Analysis and Findings - REX, page 3PST raised questions about the evolution over time of the class locations along the pipeline and encouraged the use of safety measures in Class 1 locations even though they tend to be less populated. PHMSA notes that the requirement in the special permit for the use of AMAOP IM applies to the entirety of the pipeline, including Class 1 locations. This directly address the concern raised in PST’s comment about protecting less populated Class 1 locations along the line. While population growth along pipelines is always subject to change, REX will continue to be required by the regulations to maintain continuous surveillance of its facilities to identify and address class changes and adjust its safety measures accordingly. In addition, this special permit maintains the 80 percent of specified minimum yield strength (SMYS) limit for Class 2 locations and does not extend to Class 3 location changes. In addition, PST questioned the special permit’s term for the operational life of the pipeline and asked whether periodic re-evaluations or automatic permit modification were warranted. PHMSA notes that design and construction requirements, such as those in 49 CFR § 192.620, cannot simply be retroactively satisfied at a future date. Granting a permit for the operational life of the pipeline is reasonable and obviates the need for perpetual renewals. The 2006 waiver also did not have a defined termination date or renewal requirement. REX’s compliance with the special permit conditions, as well as its compliance with other applicable regulations, will be addressed through PHMSA’s inspection and enforcement program, which includes evaluations of operator maintenance, operations, and records to confirm compliance. PST raised several other requests for additions to the permit, including the public auditing of special permit compliance, annual reporting of certain data to PHMSA and State agencies, and triggers for permit revocation. These concerns are addressed through PHMSA’s inspection program, the revocation criteria in 49 CFR § 190.341, and other applicable reporting criteria already in Federal pipeline safety regulations. For example, the AMAOP regulations address such issues as public notification (49 CFR § 190.620(d)(2)) and right-of-way protection (49 CFR § 192.620(d)(4)), and REX will continue to implement these measures on the pipeline as part of the special permit. PST also raised a question about the special permit’s one-year grace period for compliance with 49 CFR § 192.620(d)(4)(v) and (d)(7)(iv). PHMSA notes that the grace period allows REX to transition from the Common Ground Alliance Best Practices, which it implemented in accordance with the 2006 waiver, and the requirements under 49 CFR § 192.620(d)(4)(v), which are slightly different and require different documentation. PST also raised several location-specific questions, including questions regarding class changes specific to Ohio and a particular cluster of corrosion anomalies, and requested additional special permit conditions for both. PHMSA notes the special permit conditions were designed to harmonize REX’s 2006 waiver and 49 CFR § 192.620, which was promulgated after the waiver was issued to REX. Both the waiver and 49 CFR § 192.620 include enhanced IM procedures, requiring REX to address all integrity threats to the pipeline. The proposed special permit does not change these requirements. The IM measures, which are part of PHMSA’s standard regulatory structure, are well-designed to address corrosion issues and, in conjunction with any required class changes, address risks arising from population growth near the pipeline. Based on the conditions proposed in the draft special permit, PHMSA has determined that the permit is consistent with pipeline safety. PHMSA-2025-0455 – Rockies Express Pipeline, LLC Special Permit Analysis and Findings Page 3 of 5#

2025-0455 - Special Permit Analysis and Findings - REX, page 4Lastly, both PST and EDF referenced the Notice of Limited Enforcement Discretion and Statement of Policy for Issuing Special Permits in Response to National Energy Emergency issued by PHMSA on January 12, 2026. REX did not request that PHMSA consider its application in accordance with the provisions of the Notice, which is not relevant to the special permit issued in this proceeding. Analysis: Background: REX constructed this pipeline between 2005 and 2009. PHMSA issued a waiver on July 11, 2006, allowing REX to operate certain segments of the REX pipeline at a hoop stress up to 80 percent of SMYS in Class 1 locations and at a maximum allowable operating pressure (MAOP) of 1,480 pounds per square inch (Docket No. PHMSA-2006-23998, referenced herein as “2006 waiver”). The 2006 waiver also: (1) grants the REX pipeline relief from equipment requirements for pressure relieving and limiting stations, and (2) contains 46 “waiver conditions.” The waiver conditions were additional requirements exceeding those established in 49 CFR Part 192, and addressed aspects of pipeline design, construction, operations and maintenance, reporting, and IM. The requirements provided a higher level of pipeline safety relative to pipelines operated under the typical regulations in place at the time as prescribed in 49 CFR Part 192. The REX pipeline was designed, constructed, and operated under these waiver conditions from 2006 through the effective date of this special permit. Two years later, PHMSA adopted 49 CFR § 192.620, “Alternative maximum allowable operating pressure for certain steel pipelines” (“AMAOP Rule”). Pipeline Safety: Standards for Increasing the Maximum Allowable Operating Pressure for Gas Transmission Pipelines, 73 Fed. Reg. 62,148 (Oct. 17, 2008). The new AMAOP Rule allowed for operation of pipelines at an MAOP corresponding to percentage of SMYS greater than previously allowed by 49 CFR Part 192. The AMAOP Rule further established a process for managing the life cycle of a pipeline operating at a higher stress level based on experience with the waivers/special permits. As noted in the preamble to the AMAOP Rule, the requirements of the AMAOP Rule were established to codify the terms and conditions in the waivers, including the 2006 waiver, issued by PHMSA prior to publishing the AMAOP Rule. As such, the 2006 waiver conditions were a precursor to the design, construction, and operations and maintenance requirements contained in 49 CFR § 192.620. In 2022, PHMSA issued REX Special Permit PHMSA-2022-0044 to waive compliance with 49 CFR § 192.611 for Class 1 to Class 2 location changes for 20 specific segments, totaling approximately 4.25 non-contiguous miles of the REX pipeline, originally operated under the 2006 waiver. The 2022 special permit was requested because the 2006 waiver did not contemplate these types of class location changes, which are allowed on pipelines constructed under 49 CFR § 192.620. This special permit supersedes the 2006 waiver, as well as Docket No. PHMSA-2022-0044. Enforcement History: In the last 5 years, PHMSA has taken seven enforcement actions against REX. 4 Some of the prior enforcements concern matters, including class location, that are addressed by the requirements of this special permit. In the last 5 years, PHMSA has also taken 10 enforcement actions against Tallgrass Energy, 5 which owns REX. PHMSA did not identify these enforcement matters as likely to render the special permit conditions ineffective or inappropriate. PHMSA’s review of the enforcement history for REX does not indicate that granting the special permit would be inconsistent 4 See Federal Enforcement Data: REX, PHMSA, https://primis.phmsa.dot.gov/enforcement-data/operator/32163 5 See Federal Enforcement Data: Tallgrass Energy, PHMSA, https://primis.phmsa.dot.gov/enforcement-data/operator/1007 PHMSA-2025-0455 – Rockies Express Pipeline, LLC Special Permit Analysis and Findings Page 4 of 5#

2025-0455 - Special Permit Analysis and Findings - REX, page 5with pipeline safety. The enforcement data and reports used during PHMSA’s review are publicly available on PHMSA’s Enforcement Transparency website. Incident History: In the last 5 years, REX reported four incidents.6 PHMSA did not identify these prior incidents as likely to render the special permit conditions ineffective or inappropriate. PHMSA’s review of the incident history for REX does not indicate that the granting of the special permit would be inconsistent with pipeline safety. The incident data used during PHMSA’s review is publicly available on PHMSA’s Data Mart website. Findings: Based on the information submitted by REX and PHMSA’s review of the documentation, PHMSA finds that granting this special permit with conditions that waives the requirements of 49 CFR § 192.620(b)(2), (b)(4), (b)(7), (c)(1), (c)(2), (c)(3), (c)(4), (c)(5),(c)(7), (d)(6), (d)(7)(i), (d)(7)(ii), (d)(7)(iii), (d)(9), (d)(11)(ii)(a), (d)(4)(v), and (d)(7)(iv)(B) on the special permit segment of the REX pipeline system is not inconsistent with pipeline safety. This special permit requires REX to implement the special permit conditions that include applying integrity management practices to the special permit segment. Completed in Washington, D.C., on: May 27, 2026 Prepared by: PHMSA – Engineering and Research Division 6 To view this data, go to https://www.phmsa.dot.gov/data-and-statistics/pipeline/operator-information, click on Operator Search link to search for Rockies Express Pipeline, LLC, and click on the “Incidents” tab. PHMSA-2025-0455 – Rockies Express Pipeline, LLC Special Permit Analysis and Findings Page 5 of 5#