This reaction may be spontaneous at either room temperature or may occur under slight heating. Oxidizing liquids and solids can be severe fire and explosion hazards. For example, liquid air has been involved in many explosions because of its oxidizing properties. However, when liquid air evaporates, it becomes richer in oxygen content when more volatile components evaporate slightly faster.
Liquid nitrogen is safer and is preferred to liquid oxygen as a cryogenic liquid coolant.
What happens when an oxidizing material comes in contact with a combustible substance largely depends on the chemical stability of the oxidizing material. The less stable an oxidizing material is, the greater the chance that it will react in a dangerous way. The usual source of oxygen for burning is air. However, oxidizing materials can supply combustible substances with oxygen and support a fire even when air is not present. Some oxidizing materials are also incompatible with non-combustible materials.