In the bags of fertilizer it appears white, odorless, apparently harmless, but ammonium nitrate, indicated as the triggering cause of the Beirut disaster , has repeatedly sown death and destruction. Often used as a base for the production of explosives, mainly for the mining industry, it remains relatively stable at room temperature but can trigger powerful reactions in the presence of particular conditions, such as a fire or a catalyst. And no less alarming are the possible health effects of toxic substances released into the air after an explosion.
One of the effects of the explosions involving this substance - explains the expert Carlo Della Volpe of the University of Trento on the blog of the Italian Chemical Society - is the production of gaseous nitrogen oxides which, according to the risk card, are lethal by inhalation and they cause burns and even serious eye injuries, and can be very persistent in the air if they are not dispersed by the elements. Hence the concern of the Lebanese authorities about the possible consequences of the explosion on the air and on the health of the residents, who were advised to leave the city.
Ammonium nitrate, chemically a crystalline solid, in itself is not considered very dangerous for humans, and according to its safety data sheet the greatest health risk is that "it can cause serious eye irritation". Most of the one produced in the world is used in agriculture (about 93%), but the applications are different, for example in the so-called 'instant ice' which takes advantage of the fact that when it is dissolved in water it lowers its temperature. It is obtained by reacting ammonia and nitric acid, and was synthesized for the first time in 1659, although only in 1849 it was discovered that, if set on fire, it could trigger an explosion.
"The explosion of ammonium nitrate - explains Della Volpe - can be triggered by the explosion of another explosive or by the action of a catalyst mixed with the mass of material or finally by a fire sustained by combustible material mixed with it". "Beirut and Lebanon are in a difficult social and political situation like other countries in the Middle East - observes the scholar - and this certainly may have provided the context of the explosion, but remember that powerful explosions of this same type occurred in the last decades also in production plants such as in Texas in 2013 or in Toulouse in 2001, a few days from 11 September, or in the port of Tianjin in 2015 ".