Beirut port explosion: What we know from previous explosions caused by ammonium nitrate

Ammonium nitrate explosion

Gexcon investigated the detonation of approximately 20-30 tonnes of ammonium nitrate at the West Fertilizer Company storage and distribution facility in West, Texas.

According to reports on the BBC, the President of Lebanon, Michel Aoun said the blast was caused by 2,750 tonnes of ammonium nitrate stored unsafely in a warehouse.

The Middle Eastern city of Beirut was shaken by the explosion and a large orange mushroom cloud could be seen spreading over the port area.

This event has similarities to the Tianjin explosion in China which occurred on 12th August 2015 and the explosion in West, Texas, USA, in April 2013. Both of these events involved a fire which subsequently lead to the rapid decomposition of Fertilizer Grade Ammonium Nitrate.

The incident in Lebanon last night could prove to be the largest of the three in terms of blast due to the early reports about the quantity of Fertilizer Grade Ammonium Nitrate being stored. It could be equivalent to around 1,000 tonnes TNT, where Tianjin was estimated to be a blast equivalent to around 300 tonnes TNT.

Dr Scott Davis of Gexcon US performed extensive work following the explosion in West and presented a paper at the 12th Global Congress on Process Safety which discussed the investigation’s findings and lessons learnt.

Ammonium nitrate is used widely as a nitrogen fertilizer and as an additive when manufacturing explosives. It can be found naturally as a mineral and is produced by reacting anhydrous ammonia with nitric acid and dried to form small beads / prills.

Port of Tianjin, China 2015

  • 173 people died in total
  • 95 firefighters died
  • 11 police officers died
  • 707 suffered injuries


  • Nitrocellulose (guncotton) caught fire inside some containers. It was thought that a wetting agent (typically Ethanol) had flashed off due to high ambient temperatures at that time of year.
  • Fire rapidly spread to storage of other hazardous material including ammonium nitrate.
  • The area consisted of a dense occupation of industrial use combined with residential properties.
  • Approximately 5,600 families were living within a 1.5km radius of the epicentre and the closest residents were only 600m away.

West, Texas, USA, 2013

An explosion occurred at the West Fertilizer Company storage and distribution facility in West, Texas. The explosion resulted from an intense fire in the seed and storage area of the facility that led to the detonation of approximately 20-30 tonnes of ammonium nitrate stored inside a wooden receiving bin.

  • 15 people killed
  • 250 injured
  • Numerous buildings damaged and destroyed
  • Large crater formed at blast site

Investigation findings and lessons learned:

  • Heating ammonium nitrate beyond melting point causes exothermic reaction, possible runaway.
  • Energy releases temperatures 1,800°C to 2,000°C within the vicinity of the explosion.
  • Detonation due to severe shock or heating with confinement.
  • Heating causes decomposition and generation of gases which require venting.
  • Molten ammonium nitrate can cause explosive decomposition.

Click here to view a report on the Initial Investigative Facts in the West Fertilizer Explosion.

Gexcon provides a number of services for the investigation and analysis of incidents related to chemical releases and exposures, reactive chemicals, explosions, fires, vehicle and heavy machinery and HVAC (heating, ventilation, and air conditioning) and appliance failures.

It is extremely sad to see the devastation caused in Beirut last night and the long-term impact it will have on a region that is already fragile.

It is also worrying to see that explosions of this nature are continuing to happen in the 21st century. It is critical that lessons are learned to avoid the loss of life and major social and economic trauma.

It is important that such substances are handled by competent people – through training and experience.

The UK and Europe are moving in the right direction – ammonium nitrate storage falls under the COMAH/SEVESO directives.

To speak to one of our expert advisors, visit our contact page.

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