On June 15, 2022, Leo Gerard notified the board of directors (the “Board”) of Kaiser Aluminum Corporation (the “Company”) of his decision to resign as a director of the Company for personal health reasons. Mr. Gerard was designated by the United Steel, Paper and Foresting, Rubber, Manufacturing, Energy, Allied Industrial and Service Workers International Union, AFL-CIO, CLC (the “USW”) as a director candidate pursuant to the terms of the director designation agreement between the Company and the USW. Mr. Gerard's resignation was effective June 15, 2022.

The Company will coordinate with the USW to address the vacancy created by Mr. Gerard's resignation.