Ammonium nitrate linked to catastrophic Beirut explosion

Context:

Beirut was declared a “disaster city”, in the wake of a huge explosion in the port of the Lebanese capital

Ammonium nitrate, the substance used

• In its pure form, ammonium nitrate (NH4NO3) is a white, crystalline chemical that is soluble in water.
• It is the main ingredient in the manufacture of commercial explosives used in mining and construction. Regulation of Ammonium Nitrate in India
• The manufacture, conversion, bagging, import, export, transport, possession for sale, or use of ammonium nitrate is covered under The Ammonium Nitrate Rules, 2012.
• The rules also make the storage of ammonium nitrate in large quantities in populated areas illegal in India.
• For the manufacture of ammonium nitrate, an Industrial license is required under the Industrial Development and Regulation Act, 1951.
• A license under the Ammonium Nitrate Rules, 2012 is also required for any activity related to ammonium nitrate.

Is it explosive?

• Pure ammonium nitrate is not an explosive on its own. It is classified as an oxidizer under the United Nations classification of dangerous goods.
• If mixed with ingredients like fuel or some other contaminants, or because of some other external factors, it can be very explosive.
• However, for combinations to explode, triggers like detonators are required. Many Improvised Explosive Devices (IEDs) used by terrorists around the world have ANFO(ammonium nitrate fuel oil) as the main explosive, triggered by primary explosives like RDX or TNT.

Is stored ammonium nitrate a major fire hazard?

• Large quantities of stored ammonium nitrate are regarded as a major fire hazard.
• The explosion of large storage can happen primarily in two ways.
  • Contact with an explosive mixture: One is by some type of detonation or initiation because the storage comes in contact with the explosive mixture.
  • Fire or heat generation: Second, the blast can result due to a fire that starts in the ammonium nitrate store because of the heat generated due to the oxidation process at a large scale.
• There are several documented examples of deadly ammonium nitrate fire and explosion incidents in the past, some with large numbers of fatalities like in China in 2015 and Texas in 1947.