Oxygen is also used as the oxidant in torch cutting of steel. In this process, the steel is heated by an oxygen-acetylene flame, and a stream of hot oxygen is directed at the hot steel. The hot steel is oxidized by the hot oxygen and erodes away, severing the steel. The reaction of oxygen with another gas can lead to an explosion. There are two reasons why a reaction results in an explosion, and therefore, two types of explosions.
Thermal explosions result from temperature effects on the rate of a reaction.
Chain reaction explosions result from the behavior of the reacting molecules. In a thermal explosion, the heat released by the reaction increases the temperature of the reacting mixture. This increased temperature increases the rate of the reaction. If heat released by the reaction cannot escape, the rate of the reaction increases rapidly, and an explosion can result. Thus, thermal explosions are likely to occur at high pressures.