Australian academics weigh in on explosion in Beirut

Explosions in Lebanon’s capital Beirut have killed 78 people and injured thousands more, sending an enormous blast wave across the city. Lebanon’s Prime Minister, Hassan Diab, said the main blast at Beirut’s port was caused when an estimated 2750 tonnes of ammonium nitrate ignited. Diab said the chemical had been left unsecured for six years in a warehouse, and vowed to punish those responsible. Australian experts from the Australian National University and Flinders University have addressed the explosion itself, the chemical involved and the disaster response.

The explosion

Dr David Caldicott is an Emergency Consultant and Senior Clinical Lecturer in Medicine at the Australian National University. Dr Caldicott said the explosion in Beirut can be considered as a ‘high order’ explosion, with an obvious blast wave seen to be propagated from a secondary explosion that followed on from the event. Dr Caldicott believes that could have serious implications for the number and types of casualties that might be expected, with the reported number of deaths likely to be higher than currently identified.

“Ammonium nitrate is an important fertiliser, but also a key component in improvised explosives around the world,” Dr Caldicott said. “The Oklahoma bombing in 1995 involved 3–4 tonnes of the material, and it has been alleged that as much as 2600 tonnes has been involved in Beirut’s case.” Dr Caldicott used computer modelling to research the possible effects of a five-tonne ammonium nitrate/fuel oil device on the Adelaide CBD in the mid-2000s, with results showing several hundred dead and thousands injured. Shortly after, more stringent accounting of ammonium nitrate was introduced in Australia.

“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,” Dr Caldicott said.

The chemical

Associate Professor Stewart Walker, from the School of Forensic, Environmental and Analytical Chemistry at Flinders University, has interests in ammonium nitrate and other improvised explosives. “Ammonium nitrate is classified as a Dangerous Good (Australian Code for the Transport of Dangerous Goods by Road & Rail (ADG Code), 7th Edition). It is classified as ‘not flammable’ but will support a fire by providing oxygen to burn with a ‘risk of explosion’,” Associate Professor Walker said. According to Associate Professor Walker, ammonium nitrate contains two groups: the ammonia, which contains a nitrogen and four hydrogens that provide the fuel, and the nitrate, comprised of a nitrogen and three oxygens that provide the oxygen necessary for combustion. If heated, then the three components of the fire-triangle (fuel, oxygen and heat) are present.

Associate Professor Walker explained that 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 shockwave. “The video footage of the incident shows initial white/grey smoke followed by an explosion that released a large cloud of red/brown smoke and a large white ‘mushroom cloud’,” Associate Professor Walker said. “These indicate that the gases released are white ammonium nitrate fumes, toxic, red/brown nitrous oxide and water.”

Associate Professor Walker noted that other incidents have occurred in Australia, where ammonium nitrate in storage or transit caused an explosion. A truck carrying ammonium nitrate experienced an electrical fault and a fire and exploded, killing three people in Taroom, Queensland, in August 1972. Similarly, a truck carrying ammonium nitrate exploded after rolling in Wyandra, Queensland, in September 2014. “Implementation of safe handling and risk assessments have kept the number of incidents involving ammonium nitrate down,” Associate Professor Walker said.

The response

Dr Paul Gardner-Stephen, Leader of the Telecommunications Research Laboratory at Flinders University, has researched disaster and attack resilient technology. “Where the health system or other critical infrastructure is already strained, this leaves the population particularly vulnerable to tragic events such as this,” Dr Gardner-Stephen said, “as the system has little or no spare capacity to respond to the surge in demand.” Dr Gardner-Stephen believes that the current coronavirus (COVID-19) overwhelmed the supply of ventilators and intensive care beds in hospitals, along with the supply of a range of facilities.

Resultantly, lives that could have otherwise been saved following a disaster like the explosions in Lebanon will be lost. Dr Gardner-Stephen said the challenge for the global community is to find ways to help all nations to strengthen their health, water, food, communications, education and other critical infrastructure. “Preparation is always much cheaper than response, if we can find ways to afford it,” Dr Gardner-Stephen said.

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