Beirut explosion: The science behind Lebanon's massive blast
The size of Lebanon's massive explosion that killed dozens of people was likely to exacerbated by the presence of almost 3,000 kilograms of a chemical commonly used as garden fertiliser.
At least 100 people are dead and thousands are injured after Lebanon's capital Beirut was rocked by a blast so big it was registered as a 3.3 magnitude earthquake.
The exact cause of the blast is not yet known, but Lebanon's Prime Minister Hassan Diab said the explosion occurred inside a warehouse that was storing 2,750 tons of ammonium nitrate.
READ MORE: More than 100 killed in huge Beirut explosion, thousands injured
Ammonium nitrate is a white crystalline solid that is primarily used to add nitrogen to soil as a form of fertiliser.
Mr Diab said the chemical had been in the warehouse for six years.
Associate Professor Stewart Walker from the school of Forensic, Environmental and Analytical Chemistry at Flinders University said ammonium nitrate is not flammable but will "support a fire by providing oxygen to burn".
"An explosion occurs when a large amount of an energetic substance detonates, producing a large volume of confined, hot gases that expand and cause a shock wave," said Professor Walker.
"The video footage of the incident show initial white and grey smoke followed by an explosion that released a large cloud of red and brown smoke and a large white 'mushroom cloud'.
"These indicate that the gasses released are white ammonium nitrate fumes, toxic, red and brown nitrous oxide and water."
READ MORE:Trump says Beirut blast likely 'an attack'
Roger W Read, Honorary Associate Professor in the School of Chemistry at the University of New South Wales, explained that the chemical can become dangerous when mixed with organic material.
"Ammonium nitrate is a common solid fertiliser that is relatively safe by itself, although a strong oxidant, but highly dangerous when contaminated by any kind of fuel, such as oil or organic material, even in just a few per cent," said Professor Read.
"In the presence of heat, such a mixture can easily lead to catastrophic outcomes. The scale here suggests large quantities were involved."
Ammonium nitrate has been used in homemade explosive devices before.
READ MORE: 'It's heartbreaking': Scott Morrison sends condolences to family of Australian killed in Beirut blast
Security authorities believe ammonium nitrate-based explosives were used in the 1995 Oklahoma City bombing which killed 168 people and the 2011 Delhi bombing which killed 15 people.
Professor Walker explained that Australia has also seen incidents involving improper handling of ammonium nitrate.
"Other incidents have occurred where ammonium nitrate in storage or transit has caused an explosion, with widespread destruction to the surrounding area," Professor Walker said.
"Incidents in Australia involving transportation include a truck carrying ammonium nitrate that experienced an electrical fault and a fire and exploded, killing three people in Taroom, Queensland on August 30 1972 and in Wyandra, Queensland on September 6 2014 where a truck carrying ammonium nitrate exploded after rolling, destroying a bridge."
READ MORE: 'Hero' cleaner saves child from Beirut explosion
Dr David Caldicott, Emergency Consultant and Senior Clinical Lecturer in Medicine at the Australian National University, said the impact of the explosion's pressure wave on the human body is immense.
"Primary injuries are blast-related, as a consequence of the overpressure wave interacting with the hollow space in victims; lung injuries are often survived, but subsequently fatal, and bowel injuries are common," Dr Caldicott said.
"Secondary injuries are caused by flying debris; effectively environmental shrapnel. Tertiary injuries are as a consequence of being thrown by the blast, and quaternary injuries by other features such as inhalation.
"The cause of such a blast will still be under investigation - whether it was accidental or deliberate is still unclear. Given the geopolitical history of the region, either is still possible".