State PCS - West Bengal (WBCS)

• 15 Nov 2025

Ammonium Nitrate

Why in News?   

A blast near Delhi’s Red Fort has put  “Ammonium Nitrate” in the spotlight, as investigators suspect the chemical may have been used in the explosion. 

Key Points 

• About: 
  • Pure ammonium nitrate (NH₄NO₃) is a white, crystalline, water-soluble, nitrogen-rich compound made by reacting ammonia with nitric acid, and it melts at about 170°C.  
  • The substance is classified as an oxidising agent. It is one of the base ingredients used in the manufacture of commercial explosives.  
  • It is classified as a dual-use substance, meaning it has legitimate industrial uses but can also be weaponised.  
• Uses:  
  • In agriculture, it is widely used as a nitrogen fertilizer due to its high nutrient content.  
  • It is used for controlled blasting in quarries and excavation projects, and also forms a key component of various emulsions and gels used in mining-grade explosives.  
• Weaponization of Ammonium Nitrate:  
  • Pure ammonium nitrate is not explosive by itself and is classified as an oxidiser under United Nations classification of dangerous goods.   
  • It becomes volatile when combined with fuel oil, potassium chlorate, sulphur or other accelerants.  This mixture creates ANFO (Ammonium Nitrate Fuel Oil), a commonly used explosive.  
    • However, ANFO cannot detonate on its own; it requires a trigger such as a detonator, often initiated with primary explosives like RDX or TNT.