John D. Hamilton earned a M.Sc. degree at McGill University and a Ph.D. in toxicology at the University of Cincinnati. Previously Dr. Hamilton was involved with product risk assessment as a group leader in environmental toxicology and ecological risk assessment at Rohm & Haas Company. He provided modeling, risk assessment and pollution prevention support to product development teams at Rohm & Haas. He is now a Research Associate involved in research and development for S.C. Johnson Wax...Roger Sutcliffe..Contributors:.Bob Boethling, US EPA.Vincent Nabholtz, US EPA.Krzysztof M. Jop, Science Applications International Corporation.Jon Doi, Roy F. Weston, Inc..University.Michael A. Cole, University of Illinois.Larry A. Lyons and Stephen R. Vasconcellos, Betz Laboratories, Inc..