MAGELLAN PIPELINE COMPANY, LP — Warning Letter

32026001WL_Warning Letter_01212026_(25-330699)_text.pdf, page 1Official PDFU.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration 901 Locust Street, Suite 480 Kansas City, MO 64106 WARNING LETTER VIA ELECTRONIC MAIL TO: randy.lentz@oneok.com; charles.misak@oneok.com January 21, 2026 Mr. Randy Lentz President / CEO Magellan Pipeline Company, LP 100 West 5th Street Tulsa, OK 74103 CPF 3-2026-001-WL Dear Mr. Lentz: From March 11, 2025, to December 11, 2025, 1 representatives of the Pipeline and Hazardous Materials Safety Administration (PHMSA), pursuant to Chapter 601 of 49 United States Code (U.S.C.), conducted field construction inspections of the El Dorado to Wichita 8” hazardous liquid pipeline and the El Dorado to Andale 12” hazardous liquid pipeline of Magellan Pipeline Company, LP (MPC) in El Dorado, Kansas. As a result of the inspections, it is alleged that MPC has 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. § 195.202 Compliance with specifications or standards. Each pipeline system must be constructed in accordance with comprehensive written specifications or standards that are consistent with the requirements of this part. MPC did not construct the 8” El Dorado to Wichita pipeline and the 12” El Dorado to Andale pipeline in accordance with MPC’s written specifications. Specifically, MPC’s contractor did not follow the specifications for: removing the alignment clamp prior to 50% of the root bead being installed; pre-heating the pipe prior to welding; and staying within the travel speed requirements of the qualified welding procedure. 1 Construction and construction inspections of the 8” and 12” pipelines are on-going.#

32026001WL_Warning Letter_01212026_(25-330699)_text.pdf, page 2MPC’s SPECIFICATION 100—CONSTRUCTION AND FABRICATION OF PIPELINES AND RELATED PIPING SYSTEMS, section 3.1.7, indicated that “All welding, including DOT jurisdictional pipelines shall be performed in accordance with a qualified welding procedure.” The 8” and 12” pipeline construction projects utilized qualified weld procedure MAG-X60-V- G1&2-2025 which specified the qualified welding parameters for the welds. During the field visits to El Dorado to inspect the construction of the 8” and 12” lines, PHMSA observed the following instances where MPC’s contractor did not follow the welding specifications and procedures: • The qualified welding procedure specifically stated that the removal of an external clamp shall not occur until 50% of the root has been installed. In addition, section 7.2.2 of Specification 100 stated “External line-up clamps may be removed after the root bead is 50% complete, provided the completed portion of the root bead is in segments of approximately equal length, and provided the segments are equally spaced around the circumference of the pipe.” On July 15, 2025, while observing a lineup of the pipe using external clamps, a discussion between PHMSA and MPC’s inspectors occurred pertaining to removal of the alignment clamp before 50% of the root bead was done. The importance of following the specification was discussed between PHMSA and MPC representatives at the verbal exit briefing on July 16, 2025. On August 26, 2025, at tie-in location 2162+00 on the 8” line, PHMSA observed the contractor removing the external clamp at a tie-in a repair location before the root bead was 50% complete. PHMSA and the MPC inspector had another discussion about completing 50% of the root bead before removing the clamp. On December 10, 2025, at tie-in location 1576+00 on the 12” line, PHMSA, while accompanied by the MPC inspector and compliance representative, again observed a clamp removed before 50% of the root bead was installed. In this case, MPC’s contractor merely welded one side and did not weld the other side before removing the clamp. • The qualified welding procedure specifically states that when the ambient temperature is below 40⁰ F, moisture is present, or if thickness is greater than .500”, a pre-heat of the pipe is to be done to a minimum of 200⁰ F. In addition, section 7.16 of Specification 100 stated, “When preheating is required by the procedure, temperature readings shall be taken using temperature indicating crayons or direct reading pyrometers. Measurements shall be made at four locations ninety degrees apart on each side of the weld joint. The location shall be 2 inches from the weld joint center line. Maximum temperature differential between any two points shall not exceed 50⁰ F.” On October 30, 2025, PHMSA observed at station number 1271+11 on the 12” line, that MPC’s contractors were not checking to ensure that the pre-heat was meeting the requirements of the welding procedure. The ambient temperature was approximately 35⁰ F, which required 2#

32026001WL_Warning Letter_01212026_(25-330699)_text.pdf, page 3pre-heating per the procedure. When the contractor did the same on the next weld, the MPC inspector checked and found the pre-heat of the pipe to be below criteria and had them re-heat the weld. The importance of pre-heat in cold weather was discussed between PHMSA and MPC representatives at the verbal exit briefing on October 30, 2025. On December 2, 2025, at station number 864+00 on the 12” line, PHMSA again observed that MPC’s contractor was not preheating the entire weld to 200⁰ F. The ambient temperature was approximately 25⁰ F. The welder’s helper, who pre-heated the weld, stood on one side of the pipe and heated up the areas that he could reach without moving over to the other side. After the helper finished pre-heating the weld, PHMSA staff requested that the MPC inspector check the temperature on the bottom quarter of the girth weld on the opposite side of where the helper was standing. It was well below the 200⁰ F minimum. • The qualified welding procedure specifically defines the allowable travel speeds for each welding pass. On August 27, 2025, at station number 2140+00 on the 12" line, PHMSA observed that the travel speed for the root bead was exceeded as calculated by the MPC’s inspector. PHMSA and MPC’s inspectors discussed this topic, and the importance of staying within the parameter(s) of the welding procedure was subsequently relayed to MPC’s contractor. On December 4, 2025, at station number 674+00 on the 12” line, PHMSA again observed that MPC’s contractor exceeded the travel speed parameters. The hot pass was measured at 21 inches per minute. The maximum speed for the size of welding rod used was 14 inches per minute as specified in the qualified welding procedure. Again, PHMSA and the MPC inspector discussed this issue, and the MPC inspector subsequently talked to MPC’s contractor to reiterate that the parameters must be adhered to. 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 3#

32026001WL_Warning Letter_01212026_(25-330699)_text.pdf, page 431, 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 item(s) identified in this letter. Failure to do so will result in Magellan Pipeline Company, LP, 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 3-2026-001-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, David Barrett Acting Director, Central Region, Office of Pipeline Safety Pipeline and Hazardous Materials Safety Administration cc: Mr. Charles Misak, Director – Integrated Operations Services Asset Integrity 4#