The peroxy group is chemically unstable. It can easily decompose, giving off heat at a rate that increases as the temperature rises. Many organic peroxides give off flammable vapours when they decompose. These vapours can easily catch fire. Most undiluted organic peroxides can catch fire easily and burn very rapidly and intensely.
Some organic peroxides are dangerously reactive.
They can decompose very rapidly or explosively if they are exposed to only slight heat, friction, mechanical shock or contamination with incompatible materials. Organic peroxides can also be strong oxidizing agents. However, the speed of combustion in a solid medium does not exceed the speed of sound. This is one characteristic that distinguishes deflagration from detonation. Deflagrations and detonations are similar chemical reactions except that in detonations the burn rate in a solid medium is faster than the speed of sound.