Ms. Twitchell brings more than a dozen years of Board experience and 30 years of executive experience to the Board of Calumet. She was Chair of the Board of Trecora Resources (NYSE: TREC), a petrochemical and specialty wax manufacturer, until the sale of the company in June 2022. In addition, she serves on the Board of Kraton Corp and HMTX Industries. Previously she served on KMG Chemicals’ (NYSE: KMG) Board. From 2010 to 2013, Ms. Twitchell was Executive Vice President and Chief Financial Officer of Landmark Aviation, a private equity-backed fixed base operator for the aviation industry. Prior to 2010, she was Vice President and Treasurer of LyondellBasell Industries/Lyondell Chemical Company. Ms. Twitchell has also held senior management positions in the aluminum and cement manufacturing industries. Ms. Twitchell has an MBA degree from Harvard Business School and a BA in Economics from Wellesley College.