intended usages often release explosive force of deadly capacity. Nearly all widely used flash powder mixtures are sensitive to shock, friction and electrostatic discharge. In certain mixtures, it is not uncommon for this sensitivity to spontaneously change over time, or due to change in the environment, or to other unknowable factors in either the original manufacturing or in real-world storage. Additionally, accidental contaminants such as strong acids or sulfur compounds can sensitise them even more. Because flash powder mixtures are so easy to initiate, there is potentially a high risk of accidental explosions which can inflict severe blast/fragmentation injuries, e.g. blindness, explosive amputation, permanent maiming, or disfigurement. Fatalities have occurred. The various flash powder compositions should therefore not be handled by anyone who is unfamiliar with their properties, or the handling techniques required to maintain safety. Flash powder and flash powder devices pose exceptionally high risks to children, who typically cannot understand the danger and may be less adept with safe handling techniques. As a result, children tend to suffer more severe injuries than adults. Flash powders—especially those that use chlorate—are often highly sensitive to friction, heat/flame and static electricity. A spark of as little as 0.1–10 millijoules can set off certain mixtures. Certain formulations prominent in the underground press contain both sulfur and potassium chlorate. These mixtures are especially shock and friction sensitive and in many applications should be considered unpredictable. Modern pyrotechnic practices call for never using sulfur in a mix containing chlorate salts. Some flash powder formulations (those that use single-digit micrometre flake aluminium powder or fine magnesium powder as their fuel) can self-confine and explode in small quantities. This makes flash powder dangerous to handle, as it can cause severe hearing damage and amputation injury even when sitting in the open. Self-confinement occurs when the mass of the pile provides sufficient inertia to allow high pressure to build within it as the mixture reacts. This is referred to as 'inertial confinement', and it is not to be confused with a detonation. Flash powder of any formulation should not be mixed in large quantities by amateur pyrotechnicians. Beginners should start with sub-gram quantities, and refrain from making large devices. Flash powder should only be made at the site at which it will be used. Additionally, the mixture should be made immediately before use. When mixed, the transportation, storage, usage, various possession, and illegal "firearms" laws (including felonies)