We greatly appreciate the guidance, assistance, technical review, and encouragement offered by these individuals in the development of the methods and philosophy applied in this report. We would like to thank Jaime Lara for converting the ONSITE program for execution on a personal computer, and for updating, enhancing, and testing the computer program. We would like to thank Gus Rodriguez for his careful checking of dose conversion factors included in this software package and Joe Soldat and Bill Farris for their helpful technical review of the mathematical models contained in this document. We would also like to thank Kay Hopkins and Carolyn Schauls for their contributions in typing, organizing, and correcting the draft and final manuscripts. Finally, we would like to thank Virginia Brauns for her editorial assistance in the preparation of the manuscript.