Some peroxides, due to their chemical make-up, are very unstable and need to be refrigerated to avoid a self-accelerating decomposition.
Others, particularly those used for crosslinking purposes, are much more stable and can be stored at normal ambient temperatures without risk of self-acceleration.
For example, mixtures of vinyltrimethoxysilane, peroxides and stabilizers are used commercially for cross-linking polyethylene to make PEX pipe.
When thermal decomposition occurs some organic peroxide formulations release a considerable amount of gases and/or mists.
For example, carbon dioxide is a common, gaseous decomposition product for diacyl peroxides and peresters that is not flammable.
When flammable gases or mists are released as part of the decomposition there is always the potential danger of a fire or vapor phase explosion.
It is the ease of splitting the peroxy group to give two free radicals that makes organic peroxides so useful.
However, the presence of energetic free radicals during decomposition, particularly in hot gases or mists, can cause auto-ignition to occur at a lower temperature than would otherwise be normal for a similar chemical structure without the peroxy functional group.