Dr. Mark Johnson currently serves as the Director of Toxicology, US Army Public Health Center at Aberdeen Proving Ground, MD, USA. He has worked extensively in the evaluation of the toxicity of military unique compounds and the development and evaluation of a phased approach to gathering toxicity data for new compounds under development. He has authored more than 100 peer-reviewed publications, book chapters, and technical reports. He has been a member of Society of Environmental Toxicology and Chemistry and is a Steering Group Member of the Wildlife Toxicology World Interest Group and vice-chair of Ecological Risk Assessment World Interest Group.