Karen A. Twitchell

Ms. Twitchell was named a director in December 2009. From 2010 to 2013, Ms. Twitchell served as the Executive Vice President and Chief Financial Officer of Landmark Aviation. From 2001 to 2009, Ms. Twitchell was a Vice President and Treasurer of LyondellBasell Industries. Prior to that, she served as a Vice President and Treasurer of Kaiser Aluminum Corporation and Southdown, Inc. Before joining Southdown, Ms. Twitchell was an investment banker with Credit Suisse in its corporate finance department. Ms. Twitchell serves on the board of directors of Calumet Specialty Products Partners since August 2022. Ms. Twitchell served on the board of directors of KMG Chemicals, HMTX Industries and Trecora Resources.

Ms. Twitchell holds a B.A. in economics from Wellesley College and an M.B.A. from Harvard University.