The chemical name of KCIO3 is potassium chlorate. It is composed of oxygen, potassium and chlorine. It is an oxidizer and releases oxygen as it decomposes.
Potassium chlorate was once used in the manufacturing of fireworks. As it decomposes, potassium chlorate releases oxygen, which makes fireworks burn hot enough to display vivid colors. Due to safety issues, however, potassium chlorate is no longer used. When combined with sulfur, it causes an unstable reaction, and for this reason it was replaced with potassium perchlorate in fireworks production.
Potassium chlorate was used during World War I in plastic explosive construction, but this practice was also discontinued due to safety reasons.