Historically explosion accidents are linked with energetic materials. There is the further belief, that the proneness to accidents-and their severity-is linked with the sensitivity of these explosives. Consequently there exist seemingly very insensitive materials for which it is believed that their accidental explosion can be ignored, so that safety distances can be reduced to those that apply to materials for which the hazard is assumed to be mass fire rather than mass detonation. Evidence is presented here that shows these assumptions to be invalid. Reports of explosion accidents are gathered here for substances that are not generally considered to be explosives (non UN-class 1 substances, like ammonium nitrate (AN), neat alkali metal chlorates, and even hypochlorites and nitromethane). In most of these cases the proneness of accidents had not been foreseen by testing. The basic explosion mechanisms are of a more general nature than simply those that apply to high explosives. Explosion is not solely a matter of energy, but of any physical power conversion. In order to prove this, a survey of explosion events is given: Natural events, like the impacts of celestial bodies and volcanic eruptions. Fuel/liquid interactions in nature are industrial risks too, which occur at very different occasions and sites: Cellulose processing, the oil industry, foundries, power stations, explosions of hot cinders, chemical processing, fire extinguishing, and (most common) in the kitchen, and (most catastrophic) in nuclear reactors. Explosions of similar type are Hydraulic Transients, Bubble resonance explosions with the possibility associatcd chemical room explosions (BLEVE), Rollovers. Second order effects are sorption/desorption resonance explosions, which most powerful also occur in nature (Nios Lake (CO2-release), Kivu Lake, Monoun Lake, 1984, Tanganjika Lake, all in Africa, and the Ocracoke in the Gulf of Mexico (CH4-release-and at the lowest end shaken champagne bottles. All these explosions are "low probability-high risk" explosive phenomena, which are scarcely coverable by risk studies with the present day scientific tools on explosion phenomena. Up to now only in the nuclear branch a quantitative risk of explosion was brought to attention, therefore, the validity of this approach was carefully examinated.