Fireworks are big polluters, that's according to Thomas Klapötke of the University of Munich, Germany. He and his colleagues are working to change all that and are developing nitrogen-rich compounds and other strategies to ameliorate the problem of pyrotechnic pollution. Pyrotechnics isn't limited to nocturnal outdoor entertainment, other applications fall into the category - airbags, signal flares, propellants and charges for civil and military purposes. Pyrotechnic materials contain an oxidizer and a reducing agent, and depending on the application binders, propellant charges, colorants, smoke- and sound-producing agents and other compounds. Their explosive release unleashes a cascade of heavy metals and other pollutants into the atmosphere. Klapötke and his colleagues are investigating how tetrazoles and tetrazines together with nontoxic metals can be used to produce red, orange, violet, purple, and pink colored flames for use in fireworks without the pollution.