Delhi blast: What explosive materials were used, and how powerful was it?

Don't want to miss the best from Business Standard?

Two cartridges, including a live round, and samples of two different kinds of explosives were among more than 40 pieces of evidence collected by the Forensic Science Laboratory (FSL) team from the Red Fort blast site, according to a PTI report.

 

A high-intensity explosion ripped through a slow-moving vehicle near New Delhi's Red Fort traffic signal on Monday, claiming 12 lives.

 

Preliminary reports suggested that one of the samples appeared to be ammonium nitrate, a chemical often used in fertilisers but also known to act as an oxidiser in explosives when mixed with other materials. The second sample was believed to be more powerful than ammonium nitrate, PTI reported, adding that its exact composition would be confirmed after detailed forensic examination.

  Let's understand what explosives were used in the Delhi blast case and how powerful they are. 

What are explosives, how do they work?

Explosives are materials that release a huge amount of energy very quickly, producing heat, gas, and a strong shock wave. Depending on their strength, they can be classified as:

• Low explosives: Burn rapidly and create pressure (like gunpowder), causing small-scale damage
• High explosives: Detonate, thereby creating a powerful, fast-moving shock wave that causes large-scale damage.

Every explosive generally contains two parts, including a fuel that burns or reacts, and an oxidiser, which is a chemical that provides oxygen to keep the reaction going extremely fast. When these react together, there is an explosion.

Ammonium nitrate: common but dangerous

Ammonium nitrate is a white crystalline chemical mainly used in agriculture as a fertiliser. On its own, it’s generally stable. However, when mixed with fuel or exposed to intense heat or pressure, it can become highly explosive. This is why its storage and use are tightly regulated in India and worldwide.

 

According to the Times of India, the Jammu and Kashmir Police and Haryana Police uncovered a large stockpile of 2,900 kg of explosive-making material on Monday, including 360 kg of ammonium nitrate, from an apartment in Faridabad, believed to be linked to the same network behind the Delhi blast.  ALSO READ | Red Fort blast: Mobile dump data shows key suspect recced area in January

RDX, PETN: What are they?

According to media reports, investigators have also asked forensic teams to check for traces of PETN, Semtex or RDX, and detonator components.

 

RDX (Royal Demolition eXplosive): The chemical name for RDX is hexahydro-1,3,5-trinitro-1,3,5-triazine. It is a white powder and is very explosive. It is used as an explosive and is also used in combination with other ingredients in explosives. RDX is a synthetic chemical; it does not occur naturally in the environment.

 

PETN (Pentaerythritol Tetranitrate): It belongs to the class of compounds known as organic nitrates. It is used mainly as a demolition explosive and in the manufacture of detonating fuses and blasting caps.

 

Both are much more powerful than ammonium nitrate and are closely regulated because of their destructive potential.

What is a detonator?

To set off an explosion, a main charge (like RDX or ammonium nitrate) needs an initiator, known as a detonator. It is a small, controlled explosive device that gives off a quick spark, heat, or shock, which is enough to trigger the main material. For example, detonators are like a match that lights the firecracker.

 

In the Red Fort case, detonators and wires were reportedly among the materials recovered from Faridabad, suggesting the module had access to a complete improvised explosive device (IED) setup.

What is a cartridge?

The FSL team also recovered two cartridges from the blast site. A cartridge is a complete round of ammunition that includes a bullet, casing, and propellant. The discovery points to the possible presence of firearms at the scene, though investigators have not yet confirmed whether they were used in connection with the blast.

 

All the samples have been sent for forensic testing. Experts will determine the exact chemical makeup, origin, and trigger mechanism of the explosive used.