CONTANGO RESCOURCES — Warning Letter

52026003WL_Warning Letter_03192026_(25-329418)_text.pdf, page 1Official PDFU.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration 12300 W. Dakota Ave., Suite 340 Lakewood, CO 80228 WARNING LETTER VIA ELECTRONIC MAIL TO: greg.westfall@contango.com March 19, 2026 Mr. Greg Westfall Director Contango Resources 1717 South Boulder, Suite 900 Tulsa, OK 74119 CPF 5-2026-003-WL Dear Mr. Westfall: From September 22 through September 25, 2025 representatives of the Pipeline and Hazardous Materials Safety Administration (PHMSA), pursuant to Chapter 601 of 49 United States Code, (U.S.C.) inspected Contango Resource’s (Contango) Wamsutter Crude System in Wamsutter, Wyoming. As a result of the inspection, it is alleged that Contango has committed probable violations of the Pipeline Safety Regulations, Title 49, Code of Federal Regulations (CFR). The items inspected and the probable violations are: 1. § 195.402 Procedural manual for operations, maintenance, and emergencies. (a) General. Each operator shall prepare and follow for each pipeline system a manual of written procedures for conducting normal operations and maintenance activities and handling abnormal operations and emergencies. This manual shall be reviewed at intervals not exceeding 15 months, but at least once each calendar year, and appropriate changes made as necessary to ensure that the manual is effective. This manual shall be prepared before initial operations of a pipeline system commence, and appropriate parts shall be kept at locations where operations and maintenance activities are conducted.#

52026003WL_Warning Letter_03192026_(25-329418)_text.pdf, page 2Contango failed to have a written manual of procedures for conducting normal operations and maintenance activities and handling abnormal operations and emergencies, as required. Specifically, during the PHMSA inspection, Contango was unable to provide its step-by-step operating procedures for any covered task specific to the pipeline system, as defined per § 195.501(b), such as how to close a block valve during normal operations or emergencies. PHMSA reviewed Contango’s operations and maintenance manual (O&M) during the PHMSA inspection which cross referenced Standard Operating Procedures (SOPs) specific to the Wamsutter Pipeline System. The O&M also noted that the SOPs manual was located at the Wamsutter, Wyoming Field Operations Office. However, when asked, Contango was unable to provide the SOPs for review. Therefore, Contango failed to prepare and follow a manual of written procedures for normal operations, maintenance activities, abnormal operating conditions and emergencies in accordance with § 195.402(a). 2. § 194.101 Operators required to submit plans. (a) Except as provided in paragraph (b) of this section, unless OPS grants a request from a Federal On-Scene Coordinator (FOSC) to require an operator of a pipeline in paragraph (b) to submit a response plan, each operator of an onshore pipeline facility shall prepare and submit a response plan to PHMSA as provided in § 194.119. A pipeline which does not meet the criteria for significant and substantial harm as defined in § 194.103(c) and is not eligible for an exception under § 194.101(b), can be expected to cause substantial harm. Operators of substantial harm pipeline facilities must prepare and submit plans to PHMSA for review. Contango failed to submit a response plan to PHMSA as provided in § 194.119. Specifically, during inspection, Contango was unable to provide the PHMSA inspector a copy of its response plan or any proof a response plan had been prepared and submitted to PHMSA for approval in accordance with § 194.119, as required. Further, the exception for not preparing and submitting a response plan to PHMSA, as described per § 194.101(b), did not apply to the Wamsutter Crude System because the system consists of approximately 26 miles of 6-inch pipe and 6.1 miles of 8- inch pipe. Therefore, Contango failed to prepare a response plan that was reviewed and approved by PHMSA in accordance with § 194.101(a). 3. § 195.64 National Registry of Operators. (a) … (c) Changes. Each operator must notify PHMSA electronically through the National Registry of Operators at https://portal.phmsa.dot.gov, of certain events. (1) … (2) An operator must notify PHMSA of any following event not later than 60 days after the event occurs: 2#

52026003WL_Warning Letter_03192026_(25-329418)_text.pdf, page 3(i) A change in the primary entity responsible (i.e., with an assigned OPID) for managing or administering a safety program required by this part covering pipeline facilities operated under multiple OPIDs. (ii) A change in the name of the operator; (iii) A change in the entity (e.g., company, municipality) responsible for operating an existing pipeline, pipeline segment, or pipeline facility; (iv) The acquisition or divestiture of 50 or more miles of pipeline or pipeline system subject to this part; or (v) The acquisition or divestiture of an existing pipeline facility subject to this part. Contango failed to notify PHMSA of an acquisition of an existing pipeline facility subject to this part within 60 days, as required. Specifically, Western Midstream Partners, the prior owners of the Wamsutter Crude System, submitted a divestiture notification to PHMSA on August 13, 2024 with an effective date of July 31, 2024. However, Contango did not notify PHMSA it had taken responsibility of the system. Rather, PHMSA learned of Contango’s acquisition seven months later on March 25, 2025 when a PHMSA representative spoke with Contango’s Department of Transportation compliance point of contact who verified the acquisition. Therefore, Contango failed to notify PHMSA of its acquisition of an existing pipeline facility subject to Part 195 no later than 60 days after the event occurred. Under 49 U.S.C. § 60122 and 49 CFR § 190.223, you are subject to a civil penalty not to exceed $272,926 per violation per day the violation persists, up to a maximum of $2,729,245 for a related series of violations. For violation occurring on or after December 28, 2023 and before December 30, 2024, the maximum penalty may not exceed $266,015 per violation per day the violation persists, up to a maximum of $2,660,135 for a related series of violations. For violation occurring on or after January 6, 2023 and before December 28, 2023, the maximum penalty may not exceed $257,664 per violation per day the violation persists, up to a maximum of $2,576,627 for a related series of violations. For violation occurring on or after March 21, 2022 and before January 6, 2023, the maximum penalty may not exceed $239,142 per violation per day the violation persists, up to a maximum of $2,391,142 for a related series of violations. For violation occurring on or after May 3, 2021 and before March 21, 2022, the maximum penalty may not 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. 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 items identified in this letter. Failure to do so will result in Contango being subject to additional enforcement action. 3#

52026003WL_Warning Letter_03192026_(25-329418)_text.pdf, page 4No reply to this letter is required. If you choose to reply, in your correspondence please refer to CPF 5-2026-003-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, Dustin Hubbard Director, Western Region, Office of Pipeline Safety Pipeline and Hazardous Materials Safety Administration cc: PHP-60 Compliance Registry PHP-500 E. Ballado (25-329418) Randy Schrinar, Contango Resources, Pipeline Manager, randy.schrinar@contango.com 4#