The chemical behind the Beirut explosion has been a concern for years

Dozens of people in Lebanon’s port city of Beirut used their phones to capture the deadly and terrifying shockwave caused by the explosion. The pictures of charred car shells, blackened, windowless buildings and bloodied residents have shone a spotlight on the dangers of the chemical ammonium nitrate (AN). 

The Lebanese Prime Minister, Hassan Diab, says the government will punish officials whose negligence caused the accident. Ammonium nitrate is widely used as a fertiliser. It is also an explosive material essential to mining operations. Insurgents rely on it to make improvised explosive devices (IEDs). 

Experts say AN needs proper handling and storage facilities, which are designed on necessary global standards. 

“Right now it’s very difficult to say what caused the explosion. It could be anything - maybe an electric short-circuit. But what’s clear is that you need to follow all the SOPs when storing this chemical,” says Dr Shagufta Ishtiaq, the head of Karachi University’s chemical engineering department. 

“The chemical industry is legally bound to take all the necessary precautions almost everywhere in the world.” 

According to Lebananese officials, more than 2,500 tons of the chemical had been stored within a warehouse at the port for a number of years. What caused it to catch fire remains unclear, but past accidents show that AN can easily turn into a bomb under the right conditions.

Not the first time 

On its own, AN is pretty stable. However, it turns into an explosive if rapidly heated. Put it in a confined and well sealed-off space such as a warehouse - and it becomes a massive bomb. 

Before the bigger explosion at the Beirut port warehouse, there was a smaller blast. Video footage doing the rounds on Twitter show firework-like flashes popping in the plume after their initial explosion

So far, Lebanase authorities and news outlets have put the death toll at around one hundred, with thousands more having been injured. 

An even deadlier explosion involving AN occurred in 1946 in the US state of Texas. World War II had just ended and businesses were starting to use the chemical as a fertiliser, moving away from its war-years use in bombs. 

A ship, Grandcamp, loaded with 2,300 tons of AN, caught fire. Without realising what they were doing, the firefighters tried to block the vents, hoping to keep the oxygen out and kill the fire. AN, however, is an oxidising agent and does not need oxygen to burn. 

The subsequent explosions killed 581 people, injured thousands, and caused millions of dollars of damage to buildings. 

Again in Texas, an explosion at a warehouse containing some 60 tons of AN killed 15 people in 2013. 

American journalist, Joe Wertz, who wrote an extensive story on the hazards of using the chemical, explained on Twitter that efforts to tighten the safety regulations around its use have been blocked by industry groups. 

That being said, some American states keep the information about storage facilities a secret due to security concerns. There is a good reason for that. 

A man-made disaster 

In America’s worst homegrown act of terrorism, ex-Army soldier Timothy McVeigh blew up the Alfred P. Murrah Federal Building in downtown Oklahoma City using a bomb made from a cocktail of AN and diesel fuel. 168 people were killed in that attack. 

AN has also been used to make IEDs by insurgents in places such as Afghanistan. A few years ago, a fertiliser-producer in neighbouring Pakistan had to face the heat from the US government after it alleged that Pakistan-made AN was being used in explosives to target NATO soldiers. 

The company, Fatima Fertilizer, had to subsequently change the packaging of its product and better monitor the supply chain to stop its flow to militants. 

Over the years, authorities have tightened the rules that govern the trade of AN. For instance, the European Union in 2010 banned the sale of fertilisers that contained more than 16 percent of nitrogen. 

AN producers, especially if made up of a high nitrogen concentration, have to properly maintain their record books to show where the goods are stocked. 

It remains unclear just why a quantity of 2,700 tons was being stored at a Lebanese warehouse over a number of years. The country’s agriculture contributes only 5 percent to its GDP. According to one 2012 report, Lebanon - a country with a population of 6.8 million people - consumed 85,000 tons of fertilizer including AN. 

In contrast, Pakistan, which has a population of more than 210 million, uses up half a million tons of AN a year.