Carl Spreng worked from 1992 to 2018 for the Colorado Department of Public Health & Environment, in Denver, Colorado, primarily as a project manager overseeing environmental restoration at DOE's Rocky Flats Site. Prior to working for the State of Colorado, he worked as an exploration geologist on projects including uranium, coal, oil shale and tar sands evaluations and oil and gas exploration. He has served as team leader of ITRC's Radionuclides team and Attenuation Processes for Metals & Radionuclides team and as co-leader of the Remediation Management of Complex Sites team. Carl earned a bachelor's degree in 1975 and a master's in 1977, both in geology from Brigham Young University in Provo, Utah.