Video transcript:
In April 1995, a truck bomb ripped apart a building in downtown Oklahoma City. In August 2015, a series of explosions struck the port of Tianjin and northern China. And in August 2020, a campfire in Beirut triggered an explosion so strong that neighboring countries could feel it.
These were all caused by the compound ammonium nitrate, which has been implicated in at least 30 disasters and terrorist attacks in the past century.
But what is ammonium nitrate?
Well, it’s used in all sorts of things from making antibiotics to instant cold packs. And it’s an important ingredient in fertilizer.
You may be wondering: why are we using something that has the potential to be so deadly to grow food?
I like to think of ammonium nitrate as a Jekyll and Hyde chemical.
When stored properly, the meek Dr. Jekyll. Plants love it because it provides them with the nitrogen they need to grow. And although our atmosphere is mostly made up of nitrogen, plants cannot use it in that form, but in the form of nitrate.
Under the wrong conditions, ammonium nitrate can cause Dr. Jekyll’s evil alter ego, Mr. Hyde.
– – [MAN] window
– – [BOY] Are you serious?
– – [MAN] Yes. (Explosion)
What makes this normally harmless compound deadly?
First, you need a lot of it. There’s this thing called the critical diameter. This is essentially the amount of a compound you would need to detonate.
Ammonium nitrate’s critical diameter is huge, about 100 times larger than TNTs.
It’s pretty sluggish in itself. But sometimes when there is a fire near the ammonium nitrate and there is ammonium nitrate in a huge pile, ammonium nitrate can catch fire.
Once ammonium nitrate reaches 210 degrees CelsiusIt starts to melt and mainly produces a variety of gases quickly Laughing gas, Water vapor and nitrogen gas.
If these gases cannot escape, the temperatures rise and the reaction becomes faster and faster.
That alone could cause an explosion. In the case of Beirut, 6 million pounds of ammonium nitrate had not been properly stored in a warehouse and sat around soaking up moisture for nearly seven years.
And above all, although nitrate was a bit wet, it becomes very hard like cement, it is no longer a fluffy powder.
So add a fire, and the hardened ammonium nitrate will begin to heat and melt.
And then the pressure rises where the gases cannot escape.
The rate of combustion, or the speed at which ammonium nitrate burns, begins to increase.
If the burning rate is slower than the speed of sound it is a deflagration, but if it is faster than the speed of sound it causes a shock wave through the ammonium nitrate that detonates it.
However, ammonium nitrate does not have to be compressed to cause a disaster.
At the port of Tianjin, 1.7 million pounds of ammonium nitrate was stored in a warehouse near a location that also stores nitrocellulose.
In contrast to ammonium nitrate, nitrocellulose is highly flammable.
The nitrocellulose caught fire and spread to the stored ammonium nitrate, causing it to explode.
Tianjin and Beirut were some of the deadliest accidental ammonium nitrate disasters in the last century.
But terrorists have also armed the chemical. Like the 1995 Oklahoma City bombings in which terrorists detonated a truck loaded with 5,000 pounds of ammonium nitrate fertilizer, killing 168 people.
When I see a big explosion on the news, my first instinct is to ask, “Was that an accident? Or was it planned? ”
If it was a terrorist attack you would not have a fire, it will be very quick. You wouldn’t have time to watch videos, it will be done in minutes. Because what they’re doing, they have the explosives, they’re going to detonate it, cause an explosion that does the greatest possible damage, and that’s it.
Because of its proliferation and terrorist attacks, some countries have banned ammonium nitrate. In one case in 2011, the US Army detonated around 2,000 pounds of ammonium nitrate fertilizer that it had collected in Afghanistan.
It was carried out very far from households or people so that the resulting shock wave would not cause damage or injury.
Sometimes the shock wave is more deadly than the explosion itself.
A shock wave compresses the air that passes through the atmosphere, and at the top of the shock wave temperatures are between three and 4,000 degrees Celsius and the speed of the shock wave is supersonic.
So if a shock wave goes through the atmosphere when it hits windows, of course it shatters them because it pushes them out.
When it hits people, it breaks our bones because they are brittle, but the rest goes through, but it burns us because it’s very hot.
It’ll turn cars, it’ll turn ships. It will break anything brittle. Anything brittle will break when it goes through the atmosphere.
So if you find yourself in a place with a massive fire burning, move as far away from it and from windows as you can as you will not know what is burning.
So if it detonates, the shock wave that follows could be devastating.
Yes, all of this is scary. But Dr. Akhavan made it clear that we shouldn’t freak out about ammonium nitrate.
Because people are worried now, they shouldn’t be worried about ammonium nitrate. It’s safe to use. It is nothing more. It is not classified as an explosive. So it rarely goes up.
It’s only when it’s old and there’s a fire next door and also stored in large quantities. Otherwise it’s fine.
So having a bag of ammonium nitrate fertilizer in your garage is nothing to worry about. So keep using it, your tomatoes will likely thank you.
Have fun gardening.
