Production of the currently-used halogenated fire suppressants (halons) will be cunailed because of their contribution to stratospheric ozone depletion. This report, one of the first efforts toward identifying alternatives, documents the rationale for and selection of a set of approximately one hundred gases and/or liquids, covering a range of chemical and physical properties thought to affect flame suppression capability and stratospheric ozone depletion. An Appendix provides extensive information on each of the selected chemicals. Also included in the report are an introduction to combustion concepts, fire suppression mechanisms, test approaches for flame suppression effectiveness, and the mechanisms by which the current commercial halons can decrease stratospheric ozone. iii