is the Radiological Assessment Team Lead at the Centers for Disease Control and Prevention (CDC) serving as subject matter expert in CDC’s radiation emergency preparedness and response activities. He received his BS and PhD degrees in radiation biophysics from the University of Kansas, starting his career as a radiation biologist, and did his postdoctoral research in radiation-induced mutagenesis at Oak Ridge and Los Alamos National Laboratories. He was a senior scientist with the radiological consulting firm of Auxier & Associates before joining CDC in 2002. He has led the development of key national guidance documents including guides for population monitoring and operation of public shelters after radiation emergencies and a number of training products for public health professionals. He is a past president of the Health Physics Society, adjunct associate professor of nuclear and radiological engineering at Georgia Institute of Technology, member of Georgia East Metro Medical Reserve Corps and Gwinnett County Community Emergency Response Team, and provides consultancy to the International Atomic Energy Agency. Since 2014, he has served as member of the U.S. delegation to the United Nations Scientific Committee on the Effects of Atomic Radiation. He is the author of Radiation Threats and Your Safety: A Guide to Preparation and Response for Professionals and Community, a book specifically directed at audiences without radiation protection expertise.