PUBLIC NOTICE

Notice of Proposed Issuance of an
Alaska Pollutant Discharge Elimination System (APDES)
Individual Permit to Discharge to Waters of the United States

Public Notice (PN) Start Date: March 23, 2026                        PN Expiration Date: April 24, 2026

DEC has prepared an APDES draft permit for the Hilcorp Alaska, LLC – Endicott Operations. The Draft Permit and associated documents are available for a 30-day public review. Following the close of the 30-day review period, DEC will prepare a final permit, fact sheet, and response to comments. You can access the documents on DEC’s Wastewater Discharge Authorization Program webpage at: https://dec.alaska.gov/water/wastewater/.

DEC Contact: Amy Wockenfuss; Division of Water – Wastewater Discharge Authorization Program (WDAP); 555 Cordova Street (3^rd floor); Anchorage, AK 99501, (907) 269-8874, amy.wockenfuss@alaska.gov

Permit: AK0038661 – Hilcorp Alaska, LLC, Endicott Operations

Applicant:  Hilcorp Alaska LLC, Endicott Operations;
3900 Centerpoint Drive, Suite 1400; Anchorage, AK 99503

Proposed Permit Coverage: The proposed permit covers the discharge for Endicott Operations located on Duck Island in Stefansson Sound, Beaufort Sea, Alaska. The facility produces waterflood at a seawater treatment plant (STP) and distributes the waterflood for injection into oil producing formations to maintain formation pressures that enhances oil recovery. The authorized discharges include:

• Outfall 001A – Combined Outfalls 002A and 002B
  • Outfall 002A - STP and Potable Water (POW) Treatment Backwash
  • Outfall 002B - Domestic Wastewater
• Outfall 003A - Continuous Flush System

The combined discharge of the STP/POW (Outfall 002A) and Domestic Wastewater (Outfall 002B) through Outfall 001A includes the authorization of a chronic mixing zone for temperature, total residual chlorine (TRC), pH, and chronic whole effluent toxicity, as well as an acute mixing zone for TRC. There is no mixing zone authorized for Outfall 003A.

Tentative Determination: DEC has tentatively determined to reissue a discharge permit to the above listed applicant.

Written comments or requests for a public hearing on the APDES draft permit must be submitted within 30 days of the issuance of this public notice. 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/.

Alternatively, you may direct written comments and requests to the attention of the DEC contact/permit writer at the email address or postal address identified above.

All comments should include the name, address, telephone number, and email address of the commenter and a concise statement of comment on the permit condition(s) and the relevant facts upon which the comment is based. Comments of either support or concern that are directed at specific, cited permit requirements are appreciated. Mailed comments and requests must be postmarked on or before the expiration date of the public notice.

DEC will consider all substantive comments when making the final decision and will respond to received comments in a Response to Comments document issued when DEC issues a final permit. The Response to Comments will be made available to the public.

Any interested person may submit a written request for a public hearing if no hearing has already been scheduled. A request for a public hearing shall state the nature of the issues to be raised, as well as the requester’s name, address, phone number, and email. DEC will hold a public hearing whenever DEC finds, on the basis of requests, a significant degree of public interest in a draft permit. DEC may also hold a public hearing if a hearing might clarify one or more issues involved in a permit decision or for other good reason in DEC’s discretion.

DEC will transmit the final permit, fact sheet (amended as appropriate), and Response to Comments to anyone who provided comments during the public review period or requested to be notified of DEC final decision.

Deadline for Written Comments or Request for Public Hearing: April 24, 2026 at 11:59 p.m. ADST

Administrative Record: The APDES draft permit, fact sheet, permit application, and associated documents are available for public review at the DEC offices located in Anchorage, Fairbanks, Juneau, Soldotna, and Wasilla. Please contact the office of your choice to arrange for hard copies of the documents to be available for your review.

• 555 Cordova Street; Anchorage, AK 99501; 907-269-6285
• 610 University Avenue; Fairbanks, AK 99709; 907-451-2100

If you would like to see additional supporting technical documents, contact the listed DEC contact/permit writer at the phone or email address listed above.

To receive email notifications about the APDES Program, including when permits are available for review, subscribe to the APDES email list at https://list.state.ak.us/mailman/listinfo/DEC-APDES/.

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.