WEBVTT - Why Does Fertilizer Sometimes Explode?

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<v Speaker 1>Welcome to brain Stuff, a production of iHeart Radio Pay

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<v Speaker 1>brain Stuff Lauren Bogle bomb here. The fertilizer explosions that

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<v Speaker 1>have killed hundreds and injured thousands of residents in unfortunate

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<v Speaker 1>cities like Lebanon, Beirut, Breast, France, and Texas City in

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<v Speaker 1>the US are notable not only for their terrible outcomes,

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<v Speaker 1>but also because explosions from fertilizer manufacturing and storage are

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<v Speaker 1>relatively rare occurrences. For a planet that uses about two

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<v Speaker 1>hundred million tons of fertilizer a year, accidents are not ubiquitous. However,

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<v Speaker 1>when ammonium nitrate, the compound linked to all of these disasters,

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<v Speaker 1>does blow up, the effects can be devastating. On April six,

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<v Speaker 1>ninety seven, about filled with twenty three hundred tons of

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<v Speaker 1>ammonium nitrate and doctor near Texas City blew up as

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<v Speaker 1>the result of a small fire on board. Nearly six

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<v Speaker 1>hundred people were killed. That seven incident is ill one

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<v Speaker 1>of the worst industrial accidents in US history. The tragedy

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<v Speaker 1>in Lebanon in August has caused at least two d

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<v Speaker 1>and twenty deaths and five thousand injuries, and has left

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<v Speaker 1>and estimated three hundred thousand people without homes. It was

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<v Speaker 1>caused by some three thousand tons of ammonium nitrate exploding.

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<v Speaker 1>So how do fertilizers, which we often think of as

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<v Speaker 1>natural compounds that are good for the earth, explode so violently.

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<v Speaker 1>Let's begin with a little background on fertilizer itself. Plants

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<v Speaker 1>need a few basic nutrients to grow, and most of

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<v Speaker 1>them are found in the air and water and things

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<v Speaker 1>like oxygen, carbon, and hydrogen. Of course, they also need

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<v Speaker 1>some other elements that may or may not be rich

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<v Speaker 1>in the soil that they're growing in. If a plant

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<v Speaker 1>just needs a little bit of a nutrient, it's called

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<v Speaker 1>a micronutrient, think a boron or chlorine. If a plant

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<v Speaker 1>needs heaps of an ingredient, it's called a macronutrient, think nitrogen, phosphorus, potassium,

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<v Speaker 1>and sulfur. And that's where fertilizer comes in. It packs

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<v Speaker 1>the dirt with the secondary elements needed to make a

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<v Speaker 1>plant flourish. Of course, many of us home gardeners would

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<v Speaker 1>simply classify good old manure as fertilizer, and we wouldn't

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<v Speaker 1>be wrong. According to the International Fertilizer Industry Association, any

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<v Speaker 1>natural or manufactured material that contains at least five percent nitrogen, potassium,

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<v Speaker 1>or phosphorus counts as a fertilizer. Of course, the fertilizing

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<v Speaker 1>manufacturing industry produces synthetic or as they prefer to call them,

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<v Speaker 1>mineral fertilizers. To manufacture mineral fertilizers, there are a few steps. First,

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<v Speaker 1>you must collect the materials, which are in fact found

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<v Speaker 1>in nature. Then you have to treat them to bolster

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<v Speaker 1>the concentration or refine the products. After that you must

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<v Speaker 1>convert them into a form that can be used by plants,

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<v Speaker 1>and then you may want to combine those nutrients with others.

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<v Speaker 1>One of the main components in manufactured fertilizer is ammonium nitrate.

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<v Speaker 1>Like we said, nitrogen is one of those macronuts rents

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<v Speaker 1>that plants love, so a lot of fertilizers are nitrogen based.

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<v Speaker 1>Of course, we can't just bottle up some nitrogen and

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<v Speaker 1>pour it on the old carrot patch. Atmospheric nitrogen has

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<v Speaker 1>a really strong chemical bond that plants can't easily break,

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<v Speaker 1>So fertilizer companies create nitrogen based substances that are much

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<v Speaker 1>easier for plants to take. Apart ammonium nitrate is one

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<v Speaker 1>such compound, and it's used for good reason. The ammonium

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<v Speaker 1>part sticks around longer without evaporating, so it's great for

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<v Speaker 1>hot summer fields, and the nitrate is easily used by

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<v Speaker 1>plants even more compelling in the agricultural industry. It's inexpensive

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<v Speaker 1>to manufacture. You can bine ammonia and nitric acid and

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<v Speaker 1>you're done. But what makes ammonium nitrate capable of such

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<v Speaker 1>lethal explosions? Perhaps, surprisingly not much. Ammonium nitrate is a

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<v Speaker 1>relatively stable compound, according to the US Environmental Protection Agency.

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<v Speaker 1>In other words, when it's just sitting quietly somewhere, ammonium

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<v Speaker 1>n trait isn't that big of a problem because it

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<v Speaker 1>needs a relatively high activation energy, that is, the energy

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<v Speaker 1>needed to cause a chemical reaction in order to explode. However,

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<v Speaker 1>if an accident where some sort of detonation, a spark,

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<v Speaker 1>or some other kind of energy occurs, you better believe

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<v Speaker 1>that ammonium nitrate is deadly. The compound essentially makes its

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<v Speaker 1>own fuel from the ammonium and oxidizer the nitrate, so

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<v Speaker 1>its reaction is violent and long lasting. So it makes

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<v Speaker 1>sense that a fire seems to be the cause and

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<v Speaker 1>not the outcome of what happened in all of these

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<v Speaker 1>tragic explosions. It's worth repeating that although ammonium nitrate and

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<v Speaker 1>other fertilizer explosions are terrible, they're rare, but would be

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<v Speaker 1>remiss to not mention that fertilizer can also make a

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<v Speaker 1>deadly intentional weapon. Timothy McVeigh, for one, used a fertilizer

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<v Speaker 1>bomb in Oklahoma City bombing m Today's episode was written

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<v Speaker 1>by Kate Kirshner and produced by Tyler Clang. For more

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<v Speaker 1>on this and lots of other topics, visit how stuff

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<v Speaker 1>works dot com. Brain Stuff is production of I Heart

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