Ammonium Nitrate

source: Le Novel Obs

By L'Obs with AFP, august 5, 2020

translation: GoogleTranslate/doxa-louise

What is ammonium nitrate, at cause in the explosions in Beirut?

Used as the basis of many nitrogenous fertilizers, ammonium nitrate is an oxidizer which must be stored under strict conditions. It is at the origin of other tragedies, such as the explosion in a hangar of the AZF factory in 2001 in Toulouse.

In the aftermath of the explosions in Beirut which killed at least 100 people and left at least 4,000 injured according to the Lebanese Red Cross , all eyes are on ammonium nitrate, suspected of being the origin of the disaster. According to the Prime Minister, around 2,750 tons of this odorless white salt were stored in the warehouse in the port of Beirut which exploded.

Ammonium nitrate, a product to be stored under strict rules

Ammonium nitrate is used as the basis of many nitrogenous fertilizers in the form of granules. Ammonium nitrates make up  fertilizers called ammonitrates, which farmers buy in large bags or in bulk. They are not combustible products: they are oxidizers, that is, they allow the combustion of another substance already on fire.

"It's very difficult to burn ," Jimmie Oxley, professor of chemistry at the American University of Rhode Island, who herself has worked on the combustion of ammonium nitrate, told AFP . “It's not easy to detonate it. "

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Detonation is only possible with contamination by an incompatible substance or an intense source of heat. And storage must therefore follow strict rules to isolate ammonium nitrate from flammable liquids (gasoline, oils, etc.), corrosive liquids, flammable solids or even substances that give off significant heat, among others prohibited, according to  technical specifications from the French Ministry of Agriculture.

Many European countries require that calcium carbonate be added to ammonium nitrate, to create safer calcium ammonium nitrate.

In the United States, regulations regarding ammonium nitrate were tightened after the Oklahoma City bombing in 1995, where two tons of this chemical was used, killing 168 people.

Why was it stored in a warehouse in central Beirut?

The reasons for the presence of this stock of ammonium nitrate and the exact conditions for its storage are still unclear on Wednesday 5 August. But during an emergency meeting of the Supreme Defense Council, Lebanese Prime Minister Hassan Diab expressed his anger: “  It is unacceptable that a shipment of ammonium nitrate, estimated at 2,750 tonnes, be present for six years in a warehouse, without precautionary measures, ”he said.

"We will not have rest until we find the person responsible for what happened to be held to account," he promised.

"It seems that there was a warehouse containing materials confiscated many years before, and it seems that these were very explosive materials" , had indicated earlier the director general of  General Security, Abbas Ibrahim, questioned by television reporters.

Ammonium nitrate causing other disasters

Many tragedies around the world, accidental and criminal, have their origin in ammonium nitrate. One of the very first accidents killed 561 in 1921 in Oppau, Germany, in a BASF factory. In 1947, Brest was shaken by the explosion of the Norwegian freighter "Ocean Liberty" which was carrying the same substance.

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In France too, stacked in bulk in a hangar at the AZF chemical plant, in the southern suburbs of Toulouse, some 300 tonnes of ammonium nitrates suddenly exploded and caused a wind of death and desolation to blow over the fourth city of France September 21, 2001: 31 people died, and the explosion was heard 80 km around.

In the United States, a terrible explosion at the West Fertilizer fertilizer plant in West Texas left 15 people dead in 2013. A stockpile of ammonium nitrates exploded in an arson attack; the absence of storage standards had been questioned by the investigators.

A product that can be used in explosive devices

Ammonium nitrate can also be used in explosive devices. On April 19, 1995, Timothy McVeigh detonated a bomb made from two tons of the fertilizer in front of a federal building in Oklahoma City, killing 168 people.

But Professor Oxley qualifies by recalling that ammonium nitrate has become essential for agriculture and construction.

“We wouldn't have this modern world without explosives, and we couldn't feed today's peoples without ammonium nitrate fertilizers, ” she said. We need it, but you have to be really careful what you do with it. "

The Obs with AFP