WESTERN MIDSTREAM PARTNERS, LP — Warning Letter

520151010W_warning letter_11102015_text.pdf, page 1Official PDFWARNING LETTER CERTIFIED MAIL - RETURN RECEIPT REQUESTED November 10, 2015 Mrs. Jacqueline Dimpel Vice President of Midstream Anadarko Petroleum Corporation 1201 Lake Robbins Drive The Woodlands, TX 77380 CPF 5-2015-1010W Dear Mrs. Dimpel: Between July 27, 2015 and July 31, 2015, representatives of the Pipeline and Hazardous Materials Safety Administration (PHMSA), pursuant to Chapter 601 of 49 United States Code, inspected your Wyoming Gas Lines in Gillette, Wyoming. As a result of the inspection, it appears that you have committed probable violations of the Pipeline Safety Regulations, Title 49, Code of Federal Regulations. The items inspected and the probable violations are: 1. §192.603 General Provisions. (b) Each operator shall keep records necessary to administer the procedures established under §192.605. No records were available at the time of the inspection to demonstrate that the Recluse and Python compressor stations were abandoned as required by §192.727(b) Abandonment or deactivation of facilities. The records for abandonment or deactivation of facilities must be kept to ensure the procedures under §192.605 are being implemented. Subsequently, Anadarko Petroleum Corporation provided the records for abandonment or deactivation of the Recluse and Python compressor stations.#

520151010W_warning letter_11102015_text.pdf, page 22. §192.603 General Provisions. (b) Each operator shall keep records necessary to administer the procedures established under §192.605. No records were available at the time of the inspection to demonstrate that the Maximum Allowable Operating Pressure (MAOP) was determined as required by §192.619(s) Maximum allowable operating pressure – Steel or plastic pipelines. It is our understanding that your MAOPs for the 6-inch part of the MIGC to Nortex Wells (11.59 miles) built in 1983, Macsy Discharge 0.92 miles of 4-inch line built in 1994, MIGC to Manning 3.09 miles of 4-inch built in 1973, and MIGC to Powell 4.9 miles of 6-inch built in 1984 were determined by pressure test records. Subsequently, Anadarko Petroleum Corporation provided the pressure test records to address the pipeline segments listed above. Under 49 United States Code, § 60122, you are subject to a civil penalty not to exceed $200,000 per violation per day the violation persists up to a maximum of $2,000,000 for a related series of violations. For violations occurring prior to January 4, 2012, the maximum penalty may not exceed $100,000 per violation per day, with a maximum penalty not to exceed $1,000,000 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 Anadarko Petroleum Corporation 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 5-2015-1010W. 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, For Chris Hoidal Director, Western Region Pipeline and Hazardous Materials Safety Administration cc: PHP-60 Compliance Registry PHP-500 G. Ogirima (#150200) 2#