The development of a fire is a progressive process that begins with ignition and passes through several stages depending on the availability of heat, fuel, oxygen, ventilation, and the characteristics of the materials involved. In hazardous material management, understanding these stages is essential because hazardous substances may increase the speed, intensity, toxicity, or complexity of a fire. Ignition is the initial stage at which sufficient heat energy is supplied to a combustible material to start combustion. Ignition may occur through an open flame, electrical spark, hot surface, chemical reaction, friction, or spontaneous heating. For hazardous materials, vapours, gases, dusts, and flammable liquids can ignite rapidly when they reach their flammable concentration and encounter an ignition source. The material must have adequate fuel, oxygen, and heat for combustion to begin. Following ignition, the fire enters the growth stage. During this stage, the flame spreads from the original ignition point to nearby combustible materials. Heat released