Chris Hunter, a terrorist bomb disposal operator, viewed footage from the explosion which took place in Beirut on Tuesday.
Here is what he said:
1. White, pink and red smoke made it unlikely that it was gunpowder or ammunition.
When there is an explosion, it usually results in two types of smoke, black or white. If it is black, it is high explosives – the type used in military orders or terrorist car bombs.
If you see white smoke, it’s usually what we call light explosives.
It seemed to me that the dark red color came from a fire, so it could be from burning materials, furniture, or some sort of stain or paint. It could also be due to the amount of dust in the area.
High explosives detonate with a supersonic shock wave from a detonator, while weak explosives burn.
The very first thing I thought about when I saw this huge explosion was that it was very unlikely that there was any gunpowder or ammunition in an area like this. It’s more consistent with a low confined explosion, something like a fireworks explosion.
2. A simple problem like a dusty warehouse can add to the mix.
It should not be just explosive material. Quite often if you get a volatile mixture of dust and something flammable it could explode.
So when you hear about sawdust, flour mills, sweets, that sort of thing that could also cause explosions. So it could be that one of these things was on fire which then caused an explosion.
3. Lebanon’s head of internal security said the area contained highly explosive materials but not explosives – what’s the difference?
There are materials which, when the correct stimulus is introduced to them, can potentially explode under certain conditions.
So, for example, oxygen in hospitals can explode when heated enough. Calor gas is not designed to be explosive – we use it as an everyday fuel – but it can obviously explode in certain environments.
When you confine the gunpowder or the firework composition, you introduce a flame into it and it burns evenly over its entire surface. By reducing, it releases gas.
One of the peculiarities of light explosives is that if you increase the pressure you increase the burn rate, so if you confined it in a hard container so that it has nowhere to go you would get an instant explosion.
4. A team of firefighters on the scene “disappeared” after the explosion
One of the real challenges is that you don’t know how far it actually blew up.
We saw a massive explosion, but for the firefighters who went there, they are not only facing a very violent and dangerous fire, there is also potential significant loss of life, there will be significant structural damage and in plus you don’t know how much of the original explosive material is still technically intact but burning.
5. A blocked city can add to the danger
Following the 2005 assassination of former Lebanese Prime Minister Rafik al-Hariri, killed in a car bomb in central Beirut, Mr. Hunter was an expert witness in the Hague trial.
He said: “Beirut is a very densely populated city. While there are firefighters and other emergency services, any city that knows and will witness an explosion of this magnitude would have a hard time finding the resources to deal with it at first.
“One of the things in particular with Beirut’s transport infrastructure is that there is very little public transport and limited roads so there is a high risk of congestion and that will add to the challenge for first responders. “