Beirut Blast: What is ammonium nitrate that caused such a devastating explosion?

A massive explosion that shook the Lebanese capital of Beirut on Tuesday, August 4,  left over 135 people dead and thousands injured. The explosion took place around 6 pm near the headquarters of former Prime Minister Saad Hariri.

There have been several speculations regarding the cause of the explosion. According to CNN, Initially, it was blamed on a major fire at a warehouse for firecrackers near the port. But on Wednesday, August 7,  Prime Minister Hassan Diab said that about 2,750 metric tons of ammonium nitrate, a highly explosive material, had been stored at a port warehouse over the past six years without precautionary measures

What is ammonium nitrate?

Ammonium nitrate is used in fertilizer and in the mining industry as an explosive to blast rock and move mounds of earth. Ammonium nitrate has been used in terrorist attacks, such as the Oklahoma City bombing in 1995

It is said that ammonium nitrate is an oxidizer,  it intensifies combustion and allows other substances to ignite more readily, but is not itself very combustible. In this situation, a small explosion might have instigated the reaction of the ammonium nitrate

Once a reaction is sparked, ammonium nitrate explodes violently. The explosive force occurs when solid ammonium nitrate decomposes very rapidly into two gases, nitrous oxide and water vapor.

What happened in Beirut?

According to NYtimes, around  2,750 tons of ammonium nitrate fertilizer was stored in a warehouse on the Beirut waterfront and caught fire, later exploding. The fertilizer arrived in the city more than six years ago aboard a Russian-owned cargo ship that made an unscheduled stop in the city. Lebanese port officials said they made several requests to the courts to have the stockpile removed, but got no response.

The fumes in Beirut will present a health risk to residents until they naturally dissipate, which could take several days depending on the local weather

Several charities are on the ground providing medical care, shelter, supplies and other services to help the city recover and rebuild