1. National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
2. National Exposure Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA
3. National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Cincinnati, Ohio, USA
4. Department of Mathematics and Computer Science, Duquesne University, Pittsburgh, Pennsylvania, USA
5. RTI International, Research Triangle Park, North Carolina, USA
6. Rollins School of Public Health, Emory University, Atlanta, Georgia, USA
7. Department of Environmental and Occupational Health, Texas A&M University System Health Science Center, College Station, Texas, USA
8. Monsanto Company, St. Louis, Missouri, USA (retired)