The Lebanese capital, Beirut was on Tuesday hit by an explosion that killed 100 people and injured over 4,000 others.
According to the Lebanon Prime Minister Hassan Diab, 2750 tonnes of ammonium nitrate caused the explosion.
What exactly is ammonium nitrate?
Ammonium nitrate is a white crystalline substance that is mainly used in agriculture as a high-nitrogen fertilizer. It is also a key ingredient in mining explosives where it’s mixed with fuel oil and detonated by an explosive charge.
Ammonium nitrate rarely burns on its own because it acts as a source of oxygen which accelerates the burning of other materials. It can only burn on its own when exposed to extremely high temperatures as there is a rapid release of gases such as nitrogen oxides and water vapour. Meaning, a fire can cause ammonium nitrate to explode.
According to Lebanon’s National News Agency, there was a fire at the Beirut warehouse before the two explosions. The second explosion was larger than the first one as it blew out glasses and windows from buildings which were several miles away. It also overturned cars and one building collapsed from the force of the blast.
Ammonium nitrate has caused both harm and good
In the past, ammonium nitrate has been used by terrorist groups such as the Taliban as an improvised explosive. Ammonium nitrate was a component in the explosive used to bomb Oklahoma City in 1995 that killed 168 people.
After the Oklahoma bombing, the United States tightened regulations significantly. The Chemical Facility Anti-Terrorism Standards requires that facilities with more than 900 kilograms of ammonium nitrate to be inspected regularly. There are also very strict rules not to store it near fuels or sources of heat.
Many countries in the European Union require that calcium carbonate be added to ammonium nitrate to create calcium ammonium nitrate which is safer.
Though it is very harmful, ammonium nitrate is very useful in the agriculture and construction industry. Ammonium nitrate fertilizer quickly dissolves in moisture and releases nitrogen into the soil which is important for plant growth.