The fight against biological warfare has prompted investigation of the chemistry and exothermic energy from energetic material reactions as a means for the neutralization of bacterial spores. The interaction between energetic reactions containing biocides and spore forming bacteria is not well understood. The goal of this work is to fundamentally examine the mechanisms of neutralization for Bacillus thuringiensis utilizing a halogenated energetic material reaction. Spore neutralization is attributed to a thermal effect from the reaction heat and the associated chemical influence of the halogen gas (i.e., produced from combustion). Results show heat transfer in the spore enhances the effectiveness of the halogen gas in the neutralization process and that elevated temperatures increase spore permeability, facilitating gas penetration and accelerating spore neutralization. Based on experimental results, a mathematical model was developed to predict spore behavior during reaction exposure over varying time scales. In the millisecond range, the model showed that the coupled thermal-biocidal gas mechanism will require elevated temperatures of $360^{circ}C$ to produce 80% neutralization in tens of milliseconds while thermal conditions alone would require nearly $1,000^{circ}C$ for the same neutralization. These results provide molecular-level insights into the components underpinning biological processes leading to spore neutralization.