More than 100 people dead and thousands injured. This is the terrible interim balance sheet of the explosions in Beirut. A drama of which the origin is to be found in the ammonium nitrate, a salt white, and odorless used as the basis of many nitrogen fertilizers in the form of pellets. According to the lebanese Prime minister, about 2 750 tonnes of ammonium nitrate were stored in the warehouse of the port of Beirut has exploded, causing dozens of deaths and unprecedented damage in the lebanese capital. It is also the substance that had been identified during the explosion of the AZF factory in Toulouse, but only 300 tons were stored.
nitrate ammonium make up the fertilizer called ammonitrates, that farmers buy in big bags or in bulk. These are not products fuels : these are oxidizing, that is to say, they allow the combustion of another substance that is already on fire. "It is very difficult to burn it ", he said to the Agence France-Presse Jimmie Oxley, professor of chemistry at the university of Rhode Island, who has herself worked on the combustion of ammonium nitrate. "It is not easy to detonate. "The detonation is only possible with a contamination by a substance that is incompatible, or an intense source of heat. And the storage must therefore follow the rules to isolate the ammonium nitrate flammable liquids (petrol, oil...), corrosive liquids, solids flammable, or substances that emit a lot of heat, among other prohibitions, according to a fact sheet from the French ministry of Agriculture. Subjected to a high temperature, the ammonium nitrate decomposes in a reaction that releases a large amount of energy and creates a shock wave. This is the one that is linked to the blast that it was able to see on the videos, says The World. "Ammonium nitrate is toxic to humans. By inhalation of its dust, it irritates the respiratory tract ; by prolonged exposure, it causes weakness, headache, and, by contact, irritation of the skin, " says his side the chemical Society of France, relayed by RFI.
Succession of tragedies
Of the many tragedies in the world, accidental and criminal, have as a source the ammonium nitrate. One of the first accidents did 561 died in 1921, at Oppau in Germany, in a factory BASF. At the time, engineers wanting to crumble a block of several thousand tons of sulphate and ammonium nitrate, which was totally rusted have used dynamite. The explosion was heard even in the east of France. In 1947, Brest was shaken by the explosion of a Norwegian vessel Ocean Liberty carrying the substance. In France, too, stacked in bulk in a warehouse of the chemical factory AZF, in the southern suburbs of Toulouse, approximately 300 tons of ammonium nitrate suddenly detonated and is blowing a wind of death and desolation on the fourth city of France September 21, 2001 : 31 people are dead, and the explosion was heard 80 miles away. In the United States, a terrible explosion at the fertilizer plant West Fertilizer in West, Texas, had 15 deaths in 2013. A stockpile of ammonium nitrate exploded due to a fire of criminal origin ; the lack of standards for storage had been questioned by investigators.
The ammonium nitrate may also be used in explosive devices. The April 19, 1995, Timothy McVeigh had detonated a bomb made from two tonnes of manure in front of a federal building in Oklahoma City, killing 168 people. But professor Oxley nuance, recalling that the ammonium nitrate has become indispensable to agriculture and construction. "We would not have this modern world without explosives, and we could not feed the current population without fertilizers of the ammonium nitrate," she said. "We need it, but it is necessary to really pay attention to what is done with it. "As the drama the lebanese has just reminded us.