The present invention provides a new method for the in situ generation of chlorine dioxide from a solution of sodium chlorite and carbon dioxide. The present invention produces effective levels of chlorine dioxide without having to resort to the use of hydrochloric acid, sulfuric acid, hydrogen peroxide, chlorine, sulfur dioxide, or methanol. By eliminating the use of toxic and/or hazardous compounds, the present invention provides a safer means for generating and using chlorine dioxide in a wider variety of applications than previously possible. For instance, the present invention can easily be adapted for the treatment of combustion exhaust gases, flue gases, cooling towers, chilled water systems, contaminated groundwater, and agricultural produce or products.