PUBLIC NOTICE Notice of Proposed Issuance of an Alaska Pollutant Discharge Elimination System (APDES) Individual Permit to Discharge to Waters of the United States. The Alaska Department of Environmental Conservation (DEC) has tentatively determined to reissue a discharge permit for the activity described below. Permit No: AK0029840 - Hilcorp North Slope, LLC - Prudhoe Bay Seawater Treatment Plant Applicant: Hilcorp North Slope, LLC - Seawater Treatment Plant; Stefansson Sound, Beaufort Sea; 900 E. Benson Blvd.; Anchorage, Alaska 99508 Proposed Project and Location: The proposed permit covers the discharge for Prudhoe Bay Seawater Treatment Plant into Stefansson Sound, Beaufort Sea. The Facility is located at the end of the West Dock Causeway, Prudhoe Bay, Alaska and functions as a treatment and distribution point for waterflood used to maintain formation pressures to allow for enhanced oil recovery. The discharge will be permitted to occur from Outfall 001 – Strainer Backwash. The discharge of Strainer Backwash includes the authorization of a chronic mixing zone for change in temperature (ΔT) and pH. An acute mixing zone is included for total residual chlorine. A Fact Sheet, and associated documents are available for review. For inquiries or to request copies of documents, contact: Amy Wockenfuss; 555 Cordova Street, Anchorage, AK 99501, (907) 269-8874, amy.wockenfuss@alaska.gov For office locations or to view electronic copies of the permit documents, please see the DEC website at http://dec.alaska.gov/water/wastewater/. Public Notice Start Date: June 10, 2026 Expiration Date: July 10, 2026 Any person desiring to comment on the permit may submit comments electronically via the DEC public notice website (preferred) at https://dec.alaska.gov/commish/public-notices/. Comments or requests and must be submitted (mailed must be postmarked) on or before the expiration date of the public notice. A request for public hearing on the APDES draft permit must be submitted within 30 days of the issuance of this public notice. Disability Reasonable Accommodation Notice: The State of Alaska, Department of Environmental Conservation, complies with Title II of the Americans with Disabilities Act (ADA) of 1990. If you are a person with a disability who may need special accommodation in order to participate in this public process, please contact ADA Coordinator Kristin Mabry, kristin.mabry@alaska.gov, 1-907-334-0884; or TDD Relay Service 1-800-770-8973/TTY or dial 711 at least 3 days prior to the expiration/closure date of this public notice to ensure that any necessary accommodations can be provided. Pub: June 14, 2026