# Why must an oxidizer not touch rubber?

Why is it that oxidizers (specifically $\ce{KClO3}$) are at risk of causing a fire when they come into contact with the rubber stopper used to contain them in their container, but can be slowly heated if they do not contact the rubber stopper?

Essentially, why is it that oxidizers are incompatible with rubber?

• Note that an oxidiser is not combustible, it is a supporter of combustion. You need both a combustible material and a supporter if you want fire, heat is not a magical creator of fire. I'm not sure as to what the exact reaction is (oxidation of rubber) Sep 7 '12 at 6:49

$\ce{KClO3}$ and $\ce{KMnO4}$ are special kind of oxidizers, that donate oxygen very, very easy. Mixtures of this oxidizers with some reducers can self-combust on friction. Rubber stopper on regular friction produce fine powder of rubber and oxidize.