The explosion in Beirut caused by the burning of tons of ammonium nitrate – with at least 135 dead and around 4,000 injured and dozens of people missing – adds to other tragedies caused by this substance, from the accident that almost made the Belgian town of Tessenderlo disappear eighty years ago to the explosion of a chemical plant in Toulouse (southern France) in 2001 or a fertilizer factory in Texas (USA) in 2013.
The recording of what happened in the port of Beirut first shows a large amount of greyish smoke, followed by a strong explosion that caused a reddish-brown smoke and a huge white fungus.
The blast wave shattered windows, knocked down doors, shook buildings to their foundations and was felt over 200 kilometres away, all the way to Cyprus, as witnesses on social networks acknowledged.
Although the official investigation into the origin of the explosion is still pending, Lebanese Prime Minister Hasan Diab said the cause was a six-year unguarded shipment of 2,750 tonnes of ammonium nitrate, technically a soluble salt of nitric acid and ammonia, a simple chemical with the formula NH4NO3.
Beirut, half of which is now unrecognizable after two consecutive ammonium nitrate explosions, is not the first case of this type of event: more than twenty similar disasters were recorded during the 20th century, causing a total of some 2,000 deaths in different countries, from the United Kingdom, France, Poland, Mexico and Australia to the United States.
In 1942, the Belgian town of Tessenderlo also survived one of the greatest tragedies in memory because of this substance, which is still the most serious episode in the town’s history and is commemorated every year. It left 189 dead and more than 900 injured.
At the height of the Nazi occupation, the chemical plant in this Flemish municipality was destroyed after 150 tonnes of ammonium nitrate exploded, due to a shot – according to the version that has gained the most weight – although the Germans suspected that it was sabotage.
Two decades earlier, the German city of Oppau, home to the chemical group BASF, which produced explosives during World War I, was the scene of another catastrophe: the 4,000 tonnes of nitrate it had stored since the end of the conflict exploded, leaving the town and its surroundings devastated and causing 561 deaths and thousands of injured.
On 21 September 2001, an explosion occurred at the AZF ammonium nitrate factory in Toulouse, France, killing 31 people and injuring 2,500.
Three years later, two expert reports ruled out the theory of an attack or arson attack and considered it to be accidental, following a chemical reaction between ammonium nitrate and a sodium derivative stored without precaution in a factory hangar, where some 300 tons of the substance were being kept in poor condition.
The United States has a long history of incidents involving this chemical. In April 2013, the explosion of a fertilizer factory in West, Texas, after a fire, killed 15 people and injured at least 260.
Most of the victims were firefighters, mostly volunteers, who perished in the vicinity of the chemical plant, where a fire had broken out fighting a local firefighting team before the facility was blown up.
Texas City had already experienced another similar explosion in 1947, when a fire broke out on board a French freighter carrying about 2,000 tons of the chemical, resulting in 581 deaths and more than 3,000 injuried.