Dr. Stuart Willison obtained his Ph.D. in chemistry from the University of Cincinnati and has been working as a research chemist for the EPA's National Homeland Security Research Center in Cincinnati, OH for the past ten years. Since joining EPA, Dr. Willison has published numerous methods and reports related to the characterization of hazardous chemicals during remediation phases of an incident. Matrix types include, soil, water, and surfaces most commonly found in an urban setting.