It is present in water, soil and air and acts as a source of nitrogen for plants and animals. Ammonia is also produced industrially, largely as a raw material in fertilizers. A smaller proportion is used to manufacture plastics, synthetic fibers and explosives. It is not persistent in the environment, but high levels may build up around waste disposal sites. Ammonia gas is soluble in water, where it forms ammonium hydroxide.
Ammonia is highly toxic for fish and low concentrations can cause mortality.
Human exposure to high levels of ammonia gas is also fatal. Death may occur immediately or from secondary complications after a few weeks. High exposure may cause burns to the skin, eyes, throat and lungs, which, if serious, may cause permanent blindness, lung disease or death. In laboratory animals, long-term exposure to low levels of ammonia causes inflammation and lesions of the respiratory tract. It has a strong irritating odor and is used in detergents, stain removers, bleaches, dyes, fibers and resins.