This substance is an odorless white salt. It is also known as sulfuric acid or diammonium salt. It is highly soluble in water and hazardous to humans. Ammonium sulfate can be sold as a solid or in a solution as a liquid. The primary use of ammonium sulfate is in fertilizer. It works by lowering the pH of the soil to produce extra nitrogen for the plants. Conversely, it can be found in various insecticides and herbicides as well. In the food industry, this chemical is generally regarded as safe by the Food and Drug Administration, and it used as an acidity regulator in certain flours and bread. Other uses include the production of flame retardants, vaccines, and laboratory surfactants. Ammonium sulfate is mildly hazardous to humans and can cause irritation and inflammation if inhaled, ingested, or if it contacts the skin or eyes. It is also combustible at high temperatures, so it must be stored in a cool, dry area.