This invention comprises a lightweight, portable chemical combination of reagents for sterilizing or disinfecting objects in the absence of electrical power or fire. The chemical combination includes a chemical oxidant with the capacity to liberate a biocidal intermediate, a chemical reductant of the oxidant with the capacity to react with the oxidant, and an effector to induce a reaction between the oxidant and reductant. In one embodiment, the oxidant comprises chlorite, the reductant comprises sulfite, and the effector comprises ascorbate. In another embodiment, the chemical combination comprises the oxidant, reductant, effector and iron-activated magnesium. When water or water solutions are added to either embodiment, the chemical combination generates heat, steam and a biocidal intermediate that can destroy contaminating microorganisms. In one embodiment, the biocidal intermediate is a halogen-based biocidal intermediate, such as chlorine dioxide. In another embodiment, the biocidal intermediate is a halogen-free biocidal intermediate.