Abstract: In the chemical foaming of emulsions to form blasting agents, the gas-generating material (foaming agent), or a component thereof, is introduced into a stream of the emulsion and the stream thereafter delivered into packaging receivers, any work required to be performed on the emulsion after the addition of the gas-generating material thereto, e.g., pumping or mixing, being performed before substantial foaming due to reaction of the gas-generating material, as a rule before more than about 50 percent of the total density decrease attainable by foaming, has occurred. The gas-generating material can be added to a stream of fine emulsion and preferably mixed for uniform distribution through the emulsion, or to a stream of coarse emulsion, which is mixed with high shear to convert the coarse emulsion to a fine emulsion, mixing in either case taking place before substantial foaming has occurred.