Local ignition was investigated for emulsion explosives containing expanded perlite as the density control material with small sized equipment that has been referred to the French method and American method. To evaluate the safety of its manufacturing process, emulsion explosives were ignited by hot-wire at different initial temperatures. The emulsion explosives caused partial reaction that led to the rupture of steel pipe closed to the screw cap, followed by the reaction interruption without explosion. For black powder and hot-wire ignition, emulsion explosion has not sustained combustion, and all quenched. Pressure may be a key factor to previous accident and process of production for emulsion