A hazardous chemical instantly discharging gas, pressure, and heat when subjected to pressure, heat, or high temperature is categorized under hazard class I explosives by the Department of Transportation.
These are the explosives that possess the tendency to briskly detonate or conflagrate as an outcome of the chemical reaction. The explosives possess the tendency of generating pressures, temperatures, and speeds as leading to catastrophic destruction via force and/or of generating otherwise hazardous concentrations of light, heat, gas, sound, or smoke, all this resulting due to chemical reactions.
