Beirut Explosion Was 2750 Tons of Ammonium Nitrate

I eyeballed the big Beirut explosion and thought it was 1000 tons of explosive, however, it was 2750 tons of Ammonium Nitrate.

Lebanese Prime Minister Hassan Diab said an estimated 2750 tons of ammonium nitrate had been stored at a warehouse for six years. Buildings as far away as 10 kilometers from the site of the explosion were damaged. Windows were broken throughout Beirut. The blast registered as a 3.3 magnitude earthquake, the U.S. Geological Survey said.

Ammonium Nitrate is an ingredient in fertilizer – and some bombs.

The chemical has been behind several explosions in the past, both accidental and deliberate.

It was used in a terror attack in 1995 in Oklahoma City – the worst domestic terrorism on US soil. An extremist, Tim McVeigh, created a bomb of ammonium nitrate, diesel fuel, and other chemicals.

Nextbigfuture commenter Dr. Pat

Latest reports are that
1.. There was a confiscated shipment of 2750 tonnes of ammonium nitrate stored in the warehouse for the last 7 years. Just sitting there.
2.. There was a large shipment of fireworks stored next to it.
3.. The fireworks caught fire, that was the initial fire, which was itself pretty big.
4.. Then the ammonium nitrate detonated.

Calculating the yield based just on the fertilizer gives about a 2 kiloton yield.

26 thoughts on “Beirut Explosion Was 2750 Tons of Ammonium Nitrate”

  1. Catalysts just makes decomposition easier; smaller activation barrier.
    It can still decompose in an enclosed space where the only place for the heat to go is into more ammonium nitrate. If that’s efficient enough it will be self-sustaining without catalysts. Think 2 meters of ammonium nitrate with some burning wooden shelves or something in the middle burning like a blow torch to give the initial heat. That heat goes into ammonium nitrate, which then decomposes and releases more heat. This ramps exponentially until something breaks and enough heat manages to escape or the whole thing goes from deflagration to detonation.

  2. It is fertilizer. And obviously it was not hidden. How would you hide 2,750 tons of fertilizer on your boat?

  3. What possible reason could there have been to confiscate this in the first place? Insufficient bribe?

  4. Yep. Diesel is conventionally used, to the level of 4.4% to 5.8%, based on the stoichiometric composition of the diesel!  240 g of AN delivers 48 g of free oxygen (call it ‘3 moles’); Idealized, diesel is basically (CH₂)ₓ, or 14 g per mole of idealized hydrocarbon unit. In that same synthetic frame:

    3 NH₄NO₃ ⊕ 1 CH₂ → 3 N₂ ⊕ 7 H₂O ⊕ 1 CO₂ + much heat.

    ⋅-⋅-⋅ Just saying, ⋅-⋅-⋅
    ⋅-=≡ GoatGuy ✓ ≡=-⋅

  5. Ammonia by itself is a fuel. nitrate is an oxidizer. When the two are joined together you have by definition an explosive. Ammonia nitrate is an explosive however it is very difficult to detonate it. Adding an additional fuel to it however does make it easier to detonate.

  6. A shockwave from an explosion, like most all other things in the natural world, follows the path of least resistance. As well, the thermal energy of a large explosion is greatly affected by forces such as gravity. In fact, GoatGuy can correct me if I’m wrong, but without gravity, a mushroom cloud wouldn’t form.

  7. Most of the questions I have seen asked about the explosion were why it went straight up instead of out. If it had gone straight out it would have killed a LOT more. So some are speculating there was a storage area under the warehouse that had rockets or ammo in it for Hezbollah which caught fire. Fire spread up stairs or vice versa and as the floor collapsed it all went…BOOM.

  8. NH₄NO₃ → N₂ + 2H₂O + ½O₂ + heat

    The production of (N⋮ + N⋮ → N₂ + heat) is enormously exothermic. Free radical N⋮ really wants to recombine with another N⋮ if possible. Thing is, as NH₄NO₃ decomposes explosively, ALL its atomic components are momentarily in free-radical state. Thus, the N⋮ also has a really solid probability of combining with O:, to gin up (N⋮ + O: → NO (or some say N₂O₂)) the bright red-orange gas.  

    ⋅-=≡ GoatGuy ✓ ≡=-⋅

  9. I was talking specifically about the explosion / fireball itself. In terms of destruction, there was still plenty of city around the Beirut explosion, and plenty of destruction. But yes, the Beirut one is closer to the water line. So much so, that the crater got flooded, probably putting out most if not all of the fires. In Taijin, there were still major fires for several days after.

  10. In beirut 70% is “sea” distruction. There was no city all around. So you are right in your observations.

  11. I remember the Tianjin explosion looked and sounded bigger, but Wikipedia it was “just” 800 tons ammonium nitrate. That’s over 3 times smaller than this one! I suppose it looked bigger because it was at night..

  12. Just to be over pedantic: the vapor condenses BEHIND the shock-wave as the pressure behind the wave front drops, There is some footage taken from a car travelling towards the explosion and there you can see the increase refractive index of the shock wave briefly distorting the sunlight and in front of the condensation ring expanding

  13. I think we’re using different meanings of “stable” here: AN is metastable, not stable, because it can decompose exothermically. It’s got a fairly large activation energy, but while you’re not going to get an explosion if you put a match to a modest quantity of uncontained AN, (Because the reaction energy will disperse too quickly to sustain the reaction.) you certainly can make it explode if you hit it with a shock wave, or subject it to heat in a large, compacted, enclosed mass.

    It’s not the easiest thing to set off by itself, but a significant explosion and fire from fireworks could certainly accomplish it.

  14. They’re both. The nitrate group is unstable, tends to evolve into nitrogen and oxygen gas if given enough of a stimulus (plus other gases in lesser amount). But on 2nd look, you’re correct that it depends on the cation. Potassium nitrate, sodium nitrate, iron nitrate, etc are stable. But ammonium nitrate, silver nitrate, aluminum nitrate, etc are explosive. NFPA yellow rating 3: “Capable of detonation or explosive decomposition but requires a strong initiating source”. (You need to look at the yellow rating for stability; the red rating is flammability.)

    Btw, most commercial high explosives are based on either NO2 or NO3 groups, some with additional NHx groups. It’s the same principle here.

  15. Your wiki link actually makes the point that pure AN is stable, that impurities or a catalyst are needed to make it go boom:
    “Pure AN is stable and will stop decomposing once the heat source is removed, but when catalysts are present, the reaction can become self-sustaining (known as self-sustaining decomposition, or SSD). This is a well-known hazard with some types of NPK fertilizers and is responsible for the loss of several cargo ships.”

    According to reports the AN was in a storage facility with highly flammable materials for years, as AN is an oxidizer storing it with volatile fuels could have provided the impurities. ANFO is 96% AN, so not a lot of fuel required to make an explosive combination.

  16. not true,
    but yes you might add diesel (even water) to propagate nicely the shockwave for a better, complete and clean explosion. (mine school)

  17. That’s not true.
    Ammonium nitrate is not a stable molecule, and given a sufficiently sharp starting shockwave (such as having a warehouse full of fireworks catch fire) it can start to detonate itself. The shockwave of detonation will then travel through the Ammonium Nitrate until it’s all gone.

    It USED to be thought that it needed a fuel source itself, but a few shipping disasters showed this to be incorrect. There were a few ships carrying loads of fertilizer that just vanished in the open ocean and nobody knew why. Then one happened in harbour.

    Now if you WANT it to blow up, you will get a better yield if you add a fuel. Hence the famous mixture ANFO, widely used in mining. But just because the pure stuff isn’t optimal doesn’t mean it won’t go boom.

    Source: Dad used to use this fertilizer on his property, and he wanted me well aware of how much respect it needed. So I had to read up about it.

  18. As I understand it Ammonium Nitrate is just an oxidizer, it’s not even flammable until it’s mixed with a fuel such as diesel/fuel oil.

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