Footage and pictures of an explosion at Beirut’s port shocked the world last night, with over 100 people thought to be dead.
Prime Minister Boris Johnson tweeted “the pictures and videos from Beirut tonight are shocking. All of my thoughts and prayers are with those caught up in this terrible incident.”
Speculation on the cause of the explosion in the immediate aftermath was rife with social media users presenting baseless and misinformed theories of the explosion’s origin, with some suggesting it was a nuclear explosion and others claiming it was the result of a fire at a fireworks factory.
The likely cause has since been revealed with Lebanon’s Prime Minister, Hassan Diab, tweeting that 2,700 tonnes of ammonium nitrate had exploded.
It is thought that the material, used in fertilisers and explosives, had arrived in the country in 2013 and had been neglected.
What is ammonium nitrate?
Ammonium nitrate is a naturally occurring solid also known as saltpetre.
High deposits of the highly soluble compound are found in Chile’s Atacama desert, though ammonium nitrate in use today is typically synthetic.
The chemical is typically used as fertiliser due to the high presence of nitrogen.
It is also a key ingredient of ANFO (ammonium nitrate/fuel oil) which is used in industrial explosives across the world.
The chemical isn’t regarded as particularly dangerous, though in certain conditions it can be volatile.
What ignited the ammonium nitrate?
It is not yet clear how the ammonium nitrate exploded.
The material doesn’t necessarily require an external element to cause it to explode.
As ammonium nitrate decomposes it releases heat. If there is enough ammonium nitrate, this can create a fire.
When ammonium nitrate is burning it releases oxygen feeding the fire.
When heated up, the chemical can fuse together creating a plug which traps hot gases and causes an explosion when there is nowhere for said gas to escape.
What did the Lebanon PM say?
In the aftermath of the explosion Prime Minister Hassan Diab said that it was unacceptable for the chemical to be stored in a warehouse in unsafe conditions.
He tweeted: "I will not rest until we find the person responsible for what happened so we can hold them to account and impose the most severe punishment.
"It is unacceptable that a shipment of 2,750 tonnes of ammonium nitrate has been present for six years in a warehouse, without taking preventive measures and endangering the safety of citizens".