HAZMAT Class 1, based on the UNO Hazard Class and Division system, indicates Explosives, which are any substance or article, including a device, which is designed to function by explosion or which, by chemical reaction within itself is able to function in a similar manner even if not designed to function by explosion (unless, in the US, the article is otherwise classed under a provision of 49CFR).Before shipping an explosive a Special Permit is needed.