WESTERN MIDSTREAM PARTNERS, LP — Warning Letter

520176007W_Warning Letter_04042017_text.pdf, page 1Official PDFWARNING LETTER CERTIFIED MAIL - RETURN RECEIPT REQUESTED April 4, 2017 Mr. Al Walker President Anadarko Petroleum Corporation 1201 Lake Robbins Drive The Woodlands, TX 77380 CPF 5-2017-6007W Dear Mr. Walker: On October 26 through 30, 2016, and November 14 through 18, 2016, a representative of the Pipeline and Hazardous Materials Safety Administration (PHMSA), pursuant to Chapter 601 of 49 United States Code, inspected your Chipeta Pipelines and Granger-Mapco Pipeline in Vernal, Utah and Granger, Wyoming, respectively. 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. The items inspected and the probable violations are: 1. §195.412 Inspection of rights-of-way and crossings under navigable waters. (a) Each operator shall, at intervals not exceeding 3 weeks, but at least 26 times each calendar year, inspect the surface conditions on or adjacent to each pipeline right-of-way. Methods of inspection include walking, driving, flying or other appropriate means of traversing the right-of-way.#

520176007W_Warning Letter_04042017_text.pdf, page 2Anadarko Petroleum Corporation (APC) failed to inspect the surface conditions on or adjacent to each pipeline right-of-way (ROW) for the Chipeta Pipelines and Granger-Mapco Pipeline, at intervals not exceeding three (3) weeks, in accordance with §195.412(a). During the records review of APC’s ROW inspection program, it was noted that APC exceeded the three-week requirements between January 10, 2015 and February 6, 2015 for the Chipeta Pipelines. In addition, APC exceeded the three-week requirements between August 10, 2015 and September 3, 2015, between October 30, 2015 and November 24, 2015, and between December 9, 2015 and February 9, 2016 for the Granger-Mapco Pipeline. 2. §195.420 Valve maintenance. (b) Each operator shall, at intervals not exceeding 7 ½ months, but at least twice each calendar year, inspect each mainline valve to determine that it is functioning properly. APC failed to inspect each mainline valve for Granger-Mapco Pipeline, at intervals not exceeding 7 ½ months, in accordance with §195.420(b). During the records review of APC’s valve maintenance program, it was noted that APC failed to demonstrate that they performed valve inspections on the mainline valves for the second part of 2014. Additionally, APC exceeded the 7 ½-month requirements between August 18, 2015 and April 18, 2016. 3. §195.583 What must I do to monitor atmospheric corrosion control? (a) You must inspect each pipeline or portion of pipeline that is exposed to the atmosphere for evidence of atmospheric corrosion, as follows: Onshore – At least once every 3 calendar years, but with intervals not exceeding 39 months. APC failed to inspect each pipeline or portion of pipeline that is exposed to the atmosphere for evidence of atmospheric corrosion for Granger-Mapco Pipeline at least every 3 calendar years, but with intervals not exceeding 39 months, in accordance with §195.583(a). During the records review of APC’s atmospheric control program, it was noted that APC exceeded the 39-month requirement for conducting their atmospheric corrosion monitoring program. The period of monitoring was between January 25, 2012 and July 15, 2015. This interval exceeded the maximum allowable interval by 3 months. Under 49 United States Code, § 60122, you are subject to a civil penalty not to exceed $205,638 per violation per day the violation persists up to a maximum of $2,056,380 for a related series of violations. For violation occurring between January 4, 2012 to August 1, 2016, the maximum penalty may not exceed $200,000 per violation per day, with a maximum penalty not to exceed $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 2#

520176007W_Warning Letter_04042017_text.pdf, page 3this 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 5-2017-6007W. 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, Chris Hoidal Director, Western Region Pipeline and Hazardous Materials Safety Administration cc: PHP-60 Compliance Registry PHP-500 D. Fehling (#153720 and #153718) 3#