Frontier Oil Corp. has elected Robert J. Kostelnik to its Board of Directors. Currently, Kostelnik serves as President and CEO of Cinatra Clean Technologies, Inc. During his 16 years with CITGO Petroleum Corp. he held a number of senior positions including Vice President of refining, and Vice President of health, safety, security, and environment. Before joining CITGO in 1992, Kostelnik maintained various refinery management positions throughout his 17 years with Shell Oil Company. He presently serves on the Board of Directors for Methanex Corporation. Kostelnik holds a bachelore of science degree in medical engineering from the University of Missouri and is also a registered professional engineer. Frontier operates a 135,000 barrels per day refinery in El Dorado, Kansas as well as a 52,000 barrels per day refinery in Cheyenne, Wyoming.