Pyrotechnics is the science and craft of creating such things as fireworks, safety matches, oxygen candles, explosive bolts and other fasteners, parts of automotive airbags, as well as gas-pressure blasting in mining, quarrying, and demolition. This trade relies upon self-contained and self-sustained exothermic chemical reactions to make heat, light, gas, smoke and/or sound. The name comes from the Greek words pyr ("fire") and tekhnikos ("made by art"). People responsible for the safe storage, handling, and functioning of pyrotechnic devices are known as pyrotechnicians. Explosions, flashes, smoke, flames, fireworks and other pyrotechnic-driven effects used in the entertainment industry are referred to as proximate pyrotechnics. Proximate refers to the pyrotechnic device's location relative to an audience. In the majority of jurisdictions, special training and licensing must be obtained from local authorities to legally prepare and use proximate pyrotechnics. Many musical groups use pyrotechnics to enhance their live shows. Pink Floyd were innovators of pyrotechnic use in concerts. For instance, at the climax of their song "Careful with That Axe, Eugene", a blast of smoke was set off at the back of the stage. Bands such as the Who, KISS and Queen soon followed with use of pyrotechnics in their shows. Michael Jackson attempted using pyrotechnics in a 1984 Pepsi advertisement, where a stray spark caused a small fire in his hair. German industrial metal band Rammstein are renowned for their incorporation of a large variety of pyrotechnics into performances, which range from flaming costumes to face-mounted flamethrowers. Nightwish, Lordi, Sabaton and Green Day are also known for their vivid pyrotechnics in concert. Many professional wrestlers have also used pyrotechnics as part of their entrances to the ring. Modern pyrotechnics are, in general, divided into categories based upon the type of effect produced or manufacturing method. The most common categories are: Airburst - Hanging charges designed to burst into spheres of sparks.