__FORCETOC__ When heated,

ammonium nitrate Ammonium nitrate is a chemical compound with the formula . It is a white crystalline salt consisting of ions of ammonium and nitrate. It is highly soluble in water and hygroscopic as a solid, but does not form hydrates. It is predominantly us ...

decomposes non-explosively into

nitrous oxide Nitrous oxide (dinitrogen oxide or dinitrogen monoxide), commonly known as laughing gas, nitrous, or factitious air, among others, is a chemical compound, an Nitrogen oxide, oxide of nitrogen with the Chemical formula, formula . At room te ...

and

water vapor Water vapor, water vapour, or aqueous vapor is the gaseous phase of Properties of water, water. It is one Phase (matter), state of water within the hydrosphere. Water vapor can be produced from the evaporation or boiling of liquid water or from th ...

; however, it can be induced to decompose explosively by

detonation Detonation () is a type of combustion involving a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it. Detonations propagate supersonically through shock waves with ...

into

oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...

nitrogen Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...

, and water vapor. Large stockpiles of the material can be a major

fire Fire is the rapid oxidation of a fuel in the exothermic chemical process of combustion, releasing heat, light, and various reaction Product (chemistry), products. Flames, the most visible portion of the fire, are produced in the combustion re ...

risk due to their supporting

oxidation Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is ...

, and may also detonate, as happened in the

Texas City disaster The 1947 Texas City disaster was an industrial accident that occurred on April 16, 1947, in the port of Texas City, Texas, United States, located in Galveston Bay. It was the deadliest industrial accident in U.S. history and one of history's ...

of 1947 which led to major changes in the regulations for storage and handling. There are two major classes of incidents resulting in explosions: * In the first case, the explosion happens by the shock induced detonation. The initiation happens by an explosive charge going off in the mass, by the detonation of a shell thrown into the mass, or by detonation of an explosive mixture in contact with the mass. Examples are Kriewald,

Morgan Morgan may refer to: Arts and entertainment * ''Morgan – A Suitable Case for Treatment'', also called ''Morgan!'', a 1966 comedy film * ''Morgan'' (2012 film), an American drama * ''Morgan'' (2016 film), an American science fiction thriller * ...

, Oppau,

Tessenderlo Tessenderlo (; ) is a former municipality in the Belgian province of Limburg. It is where the three Belgian provinces of Limburg, Flemish Brabant and Antwerp meet at the front gate of the Averbode Abbey. The municipality Tessenderlo encompasses ...

, and Traskwood. * In the second case, the explosion results from a fire that spreads into the ammonium nitrate (AN) itself (

Texas City Texas City is a city in Galveston County, Texas, United States, on the southwest shoreline of Galveston Bay. Texas City is a deepwater port on Texas's Gulf Coast, as well as a petroleum-refining and petrochemical-manufacturing center. The popul ...

, Brest,

Tianjin Tianjin is a direct-administered municipality in North China, northern China on the shore of the Bohai Sea. It is one of the National Central City, nine national central cities, with a total population of 13,866,009 inhabitants at the time of the ...

Beirut Beirut ( ; ) is the Capital city, capital and largest city of Lebanon. , Greater Beirut has a population of 2.5 million, just under half of Lebanon's population, which makes it the List of largest cities in the Levant region by populatio ...

) or to a mixture of an ammonium nitrate with a

combustible A combustible material is a material that can burn (i.e., sustain a flame) in air under certain conditions. A material is flammable if it ignites easily at ambient temperatures. In other words, a combustible material ignites with some effort a ...

material during the fire. The fire must be confined at least to a degree for successful transition from a fire to an explosion (a phenomenon known as "deflagration to detonation transition", or

DDT Dichlorodiphenyltrichloroethane, commonly known as DDT, is a colorless, tasteless, and almost odorless crystalline chemical compound, an organochloride. Originally developed as an insecticide, it became infamous for its environmental impacts. ...

). Pure, compact AN is stable and very difficult to initiate. Ammonium nitrate decomposes in temperatures above . Pure AN is stable and will stop decomposing once the heat source is removed, but when catalysts are present, the reaction can become self-sustaining (known as self-sustaining decomposition, or SSD). This is a well-known hazard with some types of NPK fertilizers and is responsible for the loss of several cargo ships.

Timeline of major incidents

The column AN states the amount of ammonium nitrate consumed in the disaster in metric tonnes.

References

{{Ammonium nitrate disasters * Am Nitrates Explosives Industrial fires and explosions Chemical disasters History of the chemical industry

Timeline of major incidents

See also

References