This paper presents an analysis of the observed ignition behaviors of ammonium nitrate (AN) and emulsion explosives (EE). Pure AN and EE locally ignited by a heat source do not undergo sustained combustion when the pressure is lower than some threshold value usually called the Minimum Burning Pressure (MBP). A reason for pure AN's and EE's incapable of burning was suggested, and the roles of sample water, inorganic salts, oil phase, and sensitizer were discussed. Accelerating rate calorimeter (ARC) was used to study the thermal stability of EE and AN. The results also showed that MBP is of vital importance and useful for the manufacture and application of AN and EE in terms of accident prevention. (C) 2013 Elsevier Ltd. All rights reserved.