Ammonium nitrate is a chemical compound with the formula NH4NO3. It is a white crystalline salt consisting of ions of ammonium and nitrate. It is highly soluble in water and hygroscopic as a solid, although it does not form hydrates. It is predominantly used in agriculture as a high-nitrogen fertilizer.Its other major use is as a component of explosive mixtures used in mining, quarrying, and civil construction. It is the major constituent of ANFO, a popular industrial explosive which accounts for 80% of explosives used in North America; similar formulations have been used in improvised explosive devices.
Many countries are phasing out its use in consumer applications due to concerns over its potential for misuse. Accidental ammonium nitrate explosions have killed thousands of people since the early 20th century. Global production was estimated at 21.6 million tonnes in 2017. By 2021, global production of ammonium nitrate was down to 16.7 million tonnes.