Counsel for MarkWest — Pipeline Safety Interpretation

Page 11200 New Jersey Avenue, SE Washington, DC 20590 U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration October 26, 2020 Mr. Keith J. Coyle Babst, Calland, Clements and Zomnir, P.C. Counsel for MarkWest 505 9th Street, NW, Suite 700 Washington, DC 20004 Dear Mr. Coyle: In a letter to the Pipeline and Hazardous Materials Safety Administration (PHMSA), dated April 27, 2020, MarkWest requested that PHMSA clarify a statement in a supplemental interpretation issued by the agency on April 7, 2020. In the supplemental interpretation, PHMSA confirmed an earlier interpretation dated October 15, 2019, that pipelines delivering gas to MarkWest’s gas processing plant were transmission lines. PHMSA described the pipelines as delivering off-gas from refineries to the MarkWest Javelina processing plant, where the plant “uses the off-gas as chemical and plastic feedstocks and sends residue gas back to the refineries” for their use as fuel. The interpretation noted that the plant processed approximately 28,000 bbl/day of liquid hydrocarbons in this manner. PHMSA stated further that it disagreed with Markwest’s opinion that the gas processing plant is not a large volume customer for purposes of the transmission line definition in § 192.3. In its April 27, 2020 letter, MarkWest asserted that during a November 19, 2019, meeting with PHMSA, the company indicated that none of the refinery off-gas received at the plant is used as a feedstock for other products, but rather MarkWest processes the off-gas to create pipeline- quality gas for delivery to another downstream customer. Unless something has significantly changed in its processing of the feedstock into chemical feedstocks, this assertion appears to be inconsistent with information MarkWest provided to PHMSA on November 14, 2016, which explained in more detail how the Javelina plant separates off-gas into valuable components—as the off-gas contains light hydrocarbon components that are more valuable as chemical and plastic feedstocks. In addition, the information provided by MarkWest on November 14, 2016, appears to be consistent with information provided to PHMSA by the Texas Railroad Commission. The products produced include propane, butane, ethane, and other NGLs. In addition, PHMSA notes that the Javelina plant receives up to 142 mmscfd of off-gas from refineries, a volume consistent with, if not exceeding, volumes received by large volume customers. Accordingly, PHMSA finds no reason to modify its April 7, 2020, interpretation. The Pipeline and Hazardous Materials Safety Administration, Office of Pipeline Safety provides written clarifications of the Regulations (49 CFR Parts 190-199) in the form of interpretation letters. These letters reflect the agency's current application of the regulations to the specific facts presented by the person requesting the clarification. Interpretations are not generally applicable, do not create legally-enforceable rights or obligations, and are provided to help the specific requestor understand how to comply with the regulations.#

Page 22 Finally, as this pipeline is regulated by the Texas Railroad Commission, PHMSA encourages MarkWest to work directly with its regulator to resolve any future issues. Sincerely, John A. Gale Director, Office of Standards and Rulemaking The Pipeline and Hazardous Materials Safety Administration, Office of Pipeline Safety provides written clarifications of the Regulations (49 CFR Parts 190-199) in the form of interpretation letters. These letters reflect the agency's current application of the regulations to the specific facts presented by the person requesting the clarification. Interpretations are not generally applicable, do not create legally-enforceable rights or obligations, and are provided to help the specific requestor understand how to comply with the regulations.#

Page 3April 27, 2020 John A. Gale Director, Office of Standards and Rulemaking Office of Pipeline Safety (PHP-30) Pipeline and Hazardous Materials Safety Administration U.S. Department of Transportation 1200 New Jersey Avenue, S.E. Washington, DC 20590-0001 Re: Response to Supplemental Written Regulatory Interpretation Dear Mr. Gale: The Office of Pipeline Safety (OPS) recently responded to a supplemental request for written regulatory interpretation from MarkWest Javelina Pipeline Company, L.L.C. (MarkWest). In the supplemental interpretation letter, OPS affirmed the guidance provided in a prior interpretation letter that several pipelines that transport off-gas from refineries to a natural gas processing plant in Corpus Christi, Texas, should be classified as transmission lines under 49 C.F.R. Part 192. OPS also affirmed its prior guidance that the gas processing plant qualifies as a large volume customer under the transmission line definition in 49 C.F.R. § 192.3. MarkWest is respectfully requesting that OPS clarify a factual statement in the supplemental interpretation letter. Specifically, OPS states in the large volume customer analysis that “the gas processing plant uses the off-gas as chemical and plastic feedstocks[.]” However, as MarkWest indicated during its November 19, 2019, meeting with OPS staff, none of the refinery off-gas received at the Corpus Christi plant is used as a feedstock for other products. MarkWest processes the off-gas to create pipeline-quality gas for delivery to another downstream customer. To the extent that fact is material to the large volume customer analysis, MarkWest is respectfully requesting that OPS take appropriate action to clarify the supplemental interpretation letter. MarkWest appreciates OPS’s efforts in this matter. If you have any additional questions or concerns, please feel free to contact me at 202-853-3460 or kcoyle@babstcalland.com. Respectfully Submitted, /s/ Keith J. Coyle Keith J. Coyle Babst, Calland, Clements & Zomnir, P.C. 505 9th St. NW, Suite 700 Washington DC, 20004 (202) 853-3460 kcoyle@babstcalland.com Counsel for MarkWest#