New Delhi: The national capital reeled under a deadly blast near the Red Fort 10 November, when a car explosion close to the Mughal-era monument killed at least 12 people and injured dozens.
As forensic teams sift through the wreckage of charred vehicles and investigators pursue multiple leads, sources told ThePrint that Ammonium Nitrate Fuel Oil (ANFO) was suspected to have been used to cause the blast.
Hours before the blast Monday evening, a joint raid by Jammu and Kashmir and Haryana police forces in Faridabad led to the recovery of 2,500kg of explosive material, among them ammonium nitrate. Sources told ThePrint the terror module linked to the raid was also likely behind the Red Fort blast.
The suspected use of ANFO has once again turned attention to one of the most readily accessible compounds that can be combined with other materials to turn it into an explosive capable of causing mass casualties.
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What is ANFO?
ANFO, or Ammonium Nitrate Fuel Oil, is a widely used industrial explosive that primarily consists of ammonium nitrate which acts as an oxidiser, and fuel oil, typically diesel or other heavy petroleums that act as the ‘fuel’.
Unlike military-grade explosives, ANFO does not explode as powerfully or as quickly because its chemical reaction is slower and less efficient. That makes it a ‘non-ideal’ explosive, in scientific terms, though it is exactly these features that also deem it safer to handle for industrial use.
ANFO’s main advantages are its low price and simple method of production, according to the PubMed Central (PMC – National Library of Medicine).
Worldwide, the compound is used in open cast coal mining, quarrying, metal mining and civil construction—also because of its lower cost and ease of use compared to conventional industrial explosives.
How lethal is it?
The lethality of ANFO comes from a chemical reaction between its two components. Ammonium nitrate, a commonly available fertiliser, supplies oxygen for fuel oil to consume, creating gas and pressure.
While it’s a simple combustible reaction, ANFO needs to be ignited for an explosion as deadly as the Red Fort blast.
Together, these features are exploited for planning attacks without raising alarm in countries’ security apparatus.
“Nowadays, terrorists are making bombs of materials which are easily available in the market and can be purchased legally instead of the substances which are banned for security reasons. Ammonium nitrate is easily available in agricultural markets and its transportation would not raise suspicion. Also, the fuels such as petrol and diesel are available and daily-use products everywhere around the world,” said a 2019 article in Forensic Science International.
If indeed forensic analysis confirms use of the compound, investigators are likely to probe how the perpetrators of the Monday blast detonated ammonium nitrate, and whether they used a containment device to amplify its effect.
Attacks in India using ammonium nitrate
Terror attacks involving ammonium nitrate have killed dozens in the past as well.
In a response to a query in Rajya Sabha, the central government said in 2011 that ammonium nitrate was used “in various cases of terrorist/bomb blasts such as the German Bakery bomb blast case of Pune and the bomb blast near Jama Masjid in Delhi”.
On 13 February 2010, an explosion ripped through the German Bakery in Pune, killing 18 people and injuring scores of others. Forensics reports later confirmed a combination of RDX and ANFO was used to cause the blast.
The same compound was used a year later, in 2011, in the Mumbai serial blasts. More than two dozen people were killed in three blasts in Mumbai on July 13, 2011 at crowded spots near Opera House, Zaveri Bazaar and Dadar.
Before that, in 2006, seven coordinated blasts struck Mumbai’s lifeline—local trains—during the rush hours on July 11, killing more than 200 people. Here too, ammonium nitrate was used alongside RDX to increase the intensity of the explosions.
Not limited to India
A homemade ANFO explosive with two tonnes of ammonium nitrate was planted in a truck parked just outside a government building in US’ Oklahoma City in April 1995 by an ex-soldier. The explosion, considered among the worst cases of domestic terrorism in the US, killed 168.
In July 2011, the first of two attacks perpetrated by Anders Behring Breivik involved setting off a 950kg fertiliser bomb outside the Prime Minister’s Office in Oslo, Norway. Eight people died before Breivik, diagnosed with psychosis, went to an island summer camp and opened fire there.
Are there norms to regulate ANFO in India?
Keeping ammonium nitrate for long periods can be tricky, as was seen in the devastating consequence of the 2020 Beirut explosion, when nearly 2,750 tonnes of the compound lying at a port for six years got ignited by a fire in a nearby warehouse. The blast, which killed over 200 and displaced thousands, is believed to have released energy equivalent to 1.1 kilo-tonnes of TNT (trinitrotoluene).
In India, there are detailed norms for manufacturing, use, storage, imports and exports of ammonium nitrate.
The government’s 2011 response to Rajya Sabha specified that ammonium nitrate or any compound containing more than 45 percent of ammonium nitrate by weight is to be considered an “explosive” under The Explosives Act, 1884.
Among the rules to regulate and handle ammonium nitrate is the restriction on storing large quantities of the chemical in populated areas. Manufacturers need to get licences under the Industrial Development and Regulation Act, 1951, and approvals are needed for any use if the quantity exceeds 5kg.
In 2021, the government amended some rules to further safeguard the storage of ammonium nitrate after the Beirut explosion.
Despite the many norms, ammonium nitrate is readily available across the country. The 2006 Mumbai train blasts, for instance, were carried out with ANFO packed in 36 kg pressure cookers.
Monday’s recovery, including 350 kg ammonium nitrate, from two houses in rural Faridabad, just hours before the Red Fort blast, underscores the challenge of detecting a dual-use chemical that is essential for industries and agriculture, but can be weaponised just as easily.
(Edited by Ajeet Tiwari)
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