Item No. 8f - attach 2 Meeting Date: July 14, 2026 ADDENDUM TO COMMON INTEREST AND COST-SHARING AGREEMENT BY AND BETWEEN THE PORT OF SEATTLE, THE CITY OF SEATTLE, AND SOUTH PARK MARINA, L.P. This Addendum modifies the Common Interest and Cost-Sharing Agreement entered into by and between the Port of Seattle, the City of Seattle and South Park Marina, L.P., on September 1, 2018 ("Cost-Sharing Agreement") only as specified herein. Except as modified, the CostSharing Agreement remains in full force and effect as originally written. Accordingly, the Port of Seattle, the City of Seattle, and South Park Marina, L.P. ("the Parties") hereby agree that the following revisions shall be part of the Cost-Sharing Agreement: First, as a new sixth Recital: ..... WHEREAS, Ecology has asked the Parties to execute an amendment to the existing Agreed Order ("Amended Order") that requires the Parties to prepare a Feasibility Study ("FS") and Draft Cleanup Action Plan ("DCAP") to address Site Contamination ("FS/DCAP Work"), and the Parties desire to share the costs of performing FS/DCAP Work on the same terms as they performed the RI Work and to treat such costs as Shared Costs; and Second, all references to "RI Work" in the Cost-Sharing Agreement shall henceforth be deleted and replaced by: "RI Work and FS/DCAP Work," and Third, all references to "Order" in the Cost-Sharing Agreement shall henceforth be deleted and replaced by: "Order (as amended)," and Fourth, Section 17 ("Notices") is hereby amended to replace Thomas A. Newlon, as a Port of Seattle contact, with: James T. Graves Graves Environmental Law PLLC 4736 NE 187th Place Lake Forest Park, WA 98155 Phone: (206) 889-2330 E-mail: james@gravesenvirolaw.com; and to replace Tad Shimazu, as a City of Seattle contact, with: Megan Joplin Assistant City Attorney Seattle City Attorney's Office 701 Fifth Ave., Suite 2050 Seattle, WA 98104-7097 Phone: (206) 615-0885 E-mail: Megan.Joplin@seattle.gov The Parties agree that this Addendum to the Cost-Sharing Agreement may be executed by electronic signature. The Parties further agree that this Addendum constitutes and henceforth shall be presented as an integral part of the Cost-Sharing Agreement, effective as of the date last signed. IN WITNESS WHEREOF, the Parties below have executed this Addendum to the CostSharing Agreement: SOUTH PARK MARINA, L.P. OGDEN MURPHY WALLACE Guy Crow, General Partner Thomas D. Adams, Member (Counsel for South Park Marina) Date: 6/15/2026 Date: 6/8/2026 CITY OF SEATTLE CITY OF SEATTLE Jason Hamilton Seattle City Light Manager, Environmental Management & Compliance Megan Joplin Assistant City Attorney Date: Date: PORT OF SEATTLE PORT OF SEATTLE Stephen Metruck, Executive Director Elizabeth Black, Deputy General Counsel Date: Date: 2