Saltpeter is a compound chemical also known as potassium nitrate, nitric acid, and potassium salt. It is found in nature globally and has a long and varied use by human beings. The chemical formula is KNO3. It is composed of nitrate ions NO3 and potassium ions K+> It becomes increasingly soluble in water as the temperature increases. Saltpeter causes irritation of the skin and eyes and can be dangerous when ingested or inhaled. As the naturally occurring mineral niter, saltpeter is an important source of solid nitrogen. Found in high quantities in some animal manures, it has been used as a source of nitrogen fertilization in agriculture for hundreds, if not thousands, of years. It is also a major ingredient of blackpowder, is used a a fire suppressant, and has several historical and current culinary uses as a food preservative preventing botulism and as a thickening agent in foods from several cultures.