How Dangerous Is Ammonium Nitrate Used in the Delhi Blast?

The car explosion near Delhi’s Red Fort on 10 November 2025, which killed thirteen people and injured several others, has renewed focus on ammonium nitrate — a chemical compound frequently linked to both industrial use and terrorist attacks. Forensic tests indicate the likely presence of Ammonium Nitrate Fuel Oil (ANFO), a mixture often used in mining but also weaponised in major global explosions.

What Is Ammonium Nitrate?

Ammonium nitrate (NH₄NO₃) is a white, crystalline substance mainly used as a fertiliser and in construction blasting. On its own, it is not an explosive but an oxidiser that supplies oxygen for combustion. When mixed with fuel oil or diesel, it forms ANFO, which becomes a powerful explosive once initiated by a detonator. Its stability, low cost, and easy availability make it one of the most widely used industrial blasting agents worldwide.

Why Is It Favoured by Terrorists?

ANFO’s ingredients — fertiliser-grade ammonium nitrate and common fuels — are inexpensive and legally obtainable, allowing terrorists to assemble large quantities without attracting attention. When confined and detonated, the mixture produces immense heat and pressure, capable of levelling buildings and vehicles. This accessibility poses an ongoing challenge for authorities, who must regulate a dual-use chemical essential for agriculture but vulnerable to misuse.

Past Incidents Involving Ammonium Nitrate

India has witnessed multiple attacks involving ammonium nitrate-based bombs. The 2006 Mumbai train blasts and the 2010 Pune German Bakery bombing both used ANFO combined with RDX. Similarly, the 2011 Mumbai triple explosions killed over two dozen people using fertiliser-based explosives. Globally, the 1995 Oklahoma City bombing and the 2020 Beirut port explosion demonstrated how stored or weaponised ammonium nitrate can unleash catastrophic destruction when mishandled or ignited.

Exam Oriented Facts

• Ammonium nitrate becomes explosive when mixed with fuel oil, forming ANFO.
• India regulates it under the Explosives Act, 1884, with strict licensing and transport rules.
• It was used in the 2006 Mumbai train blasts, 2010 Pune blast, and 2011 Mumbai bombings.
• The 2020 Beirut blast involved 2,750 tonnes of stored ammonium nitrate, killing over 200.

RDX vs ANFO: Which Is More Dangerous?

RDX (Research Department Explosive) is far more powerful and compact than ANFO, with a detonation velocity of around 8 km per second. However, RDX is tightly controlled and used mainly by defence forces. ANFO, by contrast, is easier to obtain and can cause large-scale destruction when used in bulk, making it the weapon of choice for terrorist groups. Investigators in Delhi are now analysing residue samples to confirm whether ANFO was indeed used in the Red Fort blast, a finding that could highlight the urgent need for stricter monitoring of industrial chemicals across India.