MPLX LP — Warning Letter

12023038WL_Warning Letter_04132023_(22-233210)_text.pdf, page 1Official PDFWARNING LETTER OVERNIGHT EXPRESS DELIVERY April 13, 2023 Mr. Gregory Floerke Executive Vice President, Gathering and Processing MPLX LP 1515 Arapahoe Street, Tower 1 Suite 1600 Denver, Colorado 80202 CPF 1-2023-038-WL Dear Mr. Floerke: From August 8, 2022, through October 21, 2022, a representative of the Pipeline and Hazardous Materials Safety Administration (PHMSA) pursuant to Chapter 601 of 49 United States Code (U.S.C.) conducted an inspection of MPLX LP’s (MPLX) procedures and records in Denver, Colorado1 . As a result of the inspection, it is alleged that you have 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 insure that the manual is 1 This inspection included multiple subsidiaries of MPLX, LLC. The assets covered during this inspection included: PHMSA Operator Identification Number (OPID) 39920 for MarkWest Liberty Ethane Pipeline, L.L.C. under inspection unit number 89319; OPID 39941 for MarkWest Utica EMG, L.L.C. under inspection unit number 82542; and, OPID 39922 for Markwest Liberty NGL Pipeline, L.L.C. under inspection unit number 89319. Since the inspection, MPLX consolidated OPIDs 39920 and 39922 under OPID 40149 MPLX, LP.#

12023038WL_Warning Letter_04132023_(22-233210)_text.pdf, page 2effective. 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. MPLX failed to follow its manual of written procedures. Specifically, MPLX failed to follow its Operations, Maintenance & Emergency Manual-Liquids Program, dated 06/07/21 (OME) and its Appendix J – Accident/Incident Investigation Plan, dated 06/04/21 (Appendix J) regarding analyzing pipeline accidents to determine their cause pursuant to § 195.402(c)(5)2 . The OME Section 7.6 and Appendix J included MPLX’s detailed requirements for analyzing and documenting each failure or accident involving its liquid facilities. During the inspection, PHMSA requested records related to analyzing pipeline accidents. MPLX provided the Accident Report - PHMSA 7000.1, accident date 06/30/21 (Accident Record). The Accident Record only provided the information required by the PHMSA form which includes a narrative description of the accident that occurred. During the inspection, PHMSA requested records which supported MPLX’s emergency response and any subsequent actions taken towards documenting and analyzing the accident pursuant to their procedures. MPLX was unable to provide any supporting documentation or justification for the cause identified other than discussing that the 7000.1 report was submitted to PHMSA. The Accident Record failed to record much of the information related to the questions required by MPLX’s Appendix J. No documentation was provided during the inspection regarding any 3rd party consultations for determining the root cause of the failure or other information about the incident that was to be tracked in its Intelex system. Therefore, MPLX failed to follow its written procedures regarding analyzing a pipeline accident that occurred in calendar years 2019. 2. § 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 insure 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. MPLX failed to follow its manual of written procedures. Specifically, MPLX failed to follow its Operations, Maintenance & Emergency Manual-Liquids Program, dated 06/07/21 (OME) to 2At the time of the accident in question, 49 CFR 195.402(c)(5) stated: (a) … (c) Maintenance and normal operations. The manual required by paragraph (a) of this section must include procedures for the following to provide safety during maintenance and normal operations: (1) … (5) Analyzing pipeline accidents to determine their causes.#

12023038WL_Warning Letter_04132023_(22-233210)_text.pdf, page 3adequately document its periodic reviews of the work done by operator personnel to determine the effectiveness of the procedures used in normal operation and maintenance and taking corrective action where deficiencies are found as required by § 195.402(a). The OME Section 7.14.1 included MPLX’s requirements for conducting and documenting periodic reviews pursuant to § 195.402(c)(13)3 . During the inspection PHSMA requested records related to effectiveness reviews for calendar years 2020 and 2021. MPLX provided Operations, Maintenance and Emergencies Manual – Spot Check Performance Form, dated 11/16/20 and 03/02/21 (Effectiveness Records). The Effectiveness Records failed to indicate what reviews were conducted of the work done, what procedure was reviewed by operator personnel in normal operation and maintenance tasks and how MPLX determined if the review was effective. During the inspection, MPLX discussed how this information was included in the Section 4 – Remarks on the Effectiveness Records, however, the information on the records did not indicate relevant data to the effectiveness reviews being conducted. Therefore, MPLX failed to follow its manual of written procedures for adequately documenting periodic reviews of the work done by operator personnel to determine the effectiveness of the procedures used in normal operation and maintenance and taking corrective action where deficiencies are found in calendar years 2020 and 2021 in accordance with §§ 195.402(a) and 195.402(c)(13). 3. § 195.555 What are the qualifications for supervisors? You must require and verify that supervisors maintain a thorough knowledge of that portion of the corrosion control procedures established under §195.402(c)(3) for which they are responsible for insuring compliance. MPLX failed to verify that its supervisors maintain a thorough knowledge of that portion of the corrosion control procedures established under § 195.402(c)(3) for which they are responsible for insuring compliance. During the inspection, PHMSA requested § 195.555 corrosion control supervisor training records for calendar years 2020 and 2021. MPLX discussed the professional engineering license and industry certifications for its supervisor. However, MPLX was unable to show any records demonstrating that the supervisors’ knowledge of MPLX’s corrosion control procedures were verified. 3 § 195.402 Procedural manual for operations, maintenance, and emergencies. (a) … (c) Maintenance and normal operations. The manual required by paragraph (a) of this section must include procedures for the following to provide safety during maintenance and normal operations: (1) … (13) Periodically reviewing the work done by operator personnel to determine the effectiveness of the procedures used in normal operation and maintenance and taking corrective action where deficiencies are found.#

12023038WL_Warning Letter_04132023_(22-233210)_text.pdf, page 4After the inspection, MPLX provided the Operations, Maintenance and Emergencies Manual – Plan Review, dated 11/12/20 and Operations, Maintenance and Emergencies Program – Plan Review, dated 08/17/21 (Supervisor Records). MPLX stated that the Supervisor Records were the annual reviews of the procedures that were performed for each year. However, the personnel listed who attended the meeting were pipeline compliance department personnel, not corrosion control supervisors. Additionally, the Supervisor Records were the operations and maintenance manual annual review records and did not demonstrate how MPLX requires and verifies that its corrosion control supervisors are maintaining a thorough knowledge of its corrosion control procedures. Therefore, MPLX failed to verify that its supervisors maintain a thorough knowledge of that portion of the corrosion control procedures for which they are responsible for insuring compliance during calendar years 2020 and 2021, in accordance with § 195.555. Under 49 U.S.C. § 60122 and 49 CFR § 190.223, you are subject to a civil penalty not to 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. 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 time. We advise you to correct the items identified in this letter. Failure to do so will result in MPLX 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 1-2023-038-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).#

12023038WL_Warning Letter_04132023_(22-233210)_text.pdf, page 5Sincerely, Robert Burrough Director, Eastern Region, Office of Pipeline Safety Pipeline and Hazardous Materials Safety Administration#