Pyrotechnic displays are staples of America's birthday and other celebrations, but the chemicals that produce their eye-catching effects are nothing to cheer about. Researchers in Germany are developing cleaner combustible materials to replace the current lineup of heavy metals, dioxins and carbon monoxide that result when carbon-based fuels are oxidized. The dense, nitrogen-based chemicals under consideration yield fewer particles and less smoke without sacrificing explosive power or intensity of color.
Green fireworks are particularly toxic. These rely on barium compounds that are harmful to the heart and lungs for their hue. By replacing the barium with copper, scientists hope to preserve the color while reducing the toxicity. The new chemicals will safeguard the workers who make fireworks as well as the neck-craning public.