Is Urine (pee) Flammable?

I talk about a lot of different substances in these guides and this is one that you will either find pretty interesting or a bit disgusting. Still, there are so many questions on the subject that it is worth looking into in more detail. Is urine flammable?

Urine is generally not flammable because of its high water content. However, that doesn’t mean that all those internet tales about lighting fires are necessarily a lie.

We must get a better idea of what is true and what isn’t when it comes to the flammability of urine and urea, as well as what we should and shouldn’t do with urine in an emergency. Let’s start with some of the concerns about urine as a flammable substance, then we can move on to some of the stories about starting and putting out fires with urine.

Is Human Urine Combustible?

Urine is not going to catch on fire unless you have a bottle of the stuff and treat it in some way.

As this is not going to be an issue apart from in some very specific science experiments, you don’t have to worry about it being combustible.

It isn’t going to catch fire if you somehow end up urinating around an open flame or a spark, nor if you leave it sitting in a toilet bowl.

The water content of the urine alone is enough to ensure that it won’t catch fire. When in a toilet bowl, it just gets diluted further.

On that note, you also don’t have to worry if you have dehydration and really dark urine with a lower water content. There is still enough water for it not to become flammable.

Is Urine Flammable After Drinking Alcohol?

This is an interesting question. We know that alcohol is flammable when it is a high enough proof to sustain a flame (click that link to read another article I wrote about alcohol and flammability).

We can light drinks on fire with the right form of hard liquor. So, what are the chances of being able to light urine on fire after a night of heavy drinking?

Thankfully, the answer is that you can’t. It is impossible to get in such a state where you could try this and find it works.

Yet, I know that there will be plenty of teenagers that think it would be funny to aim their urine stream at a fire source while drunk and see what happens, so we need to provide this safety warning.

Don’t play around with fire when drunk, and don’t think that you can turn yourself into a flamethrower. It just isn’t going to happen.

You would need to have an excessive blood alcohol content to have enough alcohol in your urine for it to light on fire.

By this point, you wouldn’t just be unable to stand and pee under your own willpower. You would be at great risk of alcohol toxicity and death.

What About Urea?

Let’s get back to the safer and more scientific side of urine flammability.

Another question of interest relates to the concentrated form of urine and the chemicals within it. Urine isn’t 100% water, as there are also waste products from the kidneys such as ammonia and urea.

While these could be considered flammable on their own, and if all the water content disappeared, there is still not much to worry about.

Is Animal Urine Flammable?

It is worth asking about animal urine as this is more likely to be left lying around than human urine.

You might have a puppy that still has a habit of peeing on the carpet, a cat with bladder issues, or some other creature leaving its mark.

As this will dry out and seep into flammable materials like carpets and upholstery, it is fair to worry about any added dangers.

But, this urine is no riskier than ours because of similar factors to the water and chemical contents.

Even when it dries out, it isn’t going to make your carpet any more flammable than it already is.

This also means that there is nothing to worry about if your pet pees on the path or driveway and leaves a puddle behind. Just let it wash away with no concern about any fire hazards – and watch where you walk.

Is Urine Explosive?

This may sound like a strange question about bodily fluid, but there is a reason for it. You see, there are stories about containers of urine exploding.

Why have urine in containers?

Well, this tends to happen mostly at festivals and other situations where attendees are left with a dilemma on where to go.

By the end of a weekend, those porta-potties aren’t in a great state and may not even be working. While the logical second choice would be to just go behind a bush or a tree, some people choose to pee in bottles and leave those out near the toilets.

In some cases, these will explode.

However, this is more to do with the conditions and the bottle than the urine. The best thing to do here is simply to avoid the risk altogether and not leave urine in bottles.

Can You Use Urine To Start A Campfire?

Another common story you see online is that people have used their urine to start a fire. Without context, this sounds like people either urinated onto firewood to set it alight or ignited a stream of urine in some way.

But, if you have a means to light the urine on fire, why would you need the urine in the first place? While this all sounds far-fetched, there is a way to use urine to start a fire, and it involves a bottle.

The idea here is that you pee into a bottle, screw the cap on, and place the bottle upside down in the rays of the sun.

This should allow for a concentrated refracted beam of light. You can then aim this beam at a form of tinder in your firewood. A piece of paper or steel wool would work brilliantly here.

Eventually, the bottle will act like a magnifying glass and you will get a beam hot enough to set light to the tinder. The downside is that you’re going to be standing around with a bottle full of urine for a while.

You will also need enough urine to fill enough of the bottle to make this effective – which is easier said than done.

While this all sounds clever and like the ideal hack for survivalist camping, there isn’t any need to go to this much trouble if you have water on you, or within easy reach.

A bottle of water will produce the same effects as it is more about the presence of liquid than its origin.

Of course, if you are out of the water, urine may have to suffice.

I also want to add that while this seems like a good reason for having a bottle of pee in need of disposal, and perhaps why festival attendants find so many, you can just tip it away after use.

Can You Use Urine To Put Out A Fire?

Theoretically, you could do this, as the water content in the urine and a large enough stream might be enough to deal with a small fire.

But, there are sure to be better options available. Peeing on fire isn’t pleasant because of the risk of it splashing around and the smell of the liquid heated up in the flames.

There is also the risk of exposing sensitive areas of your anatomy in the vicinity of flames. It is much better for all concerned to try and find some water or another way to remove the oxygen or fuel source from the fire.

Can You Use Urine To Treat Burns?

Again, this is one of those options where you could if you wanted to, as studies have shown urine to be effective on rat test subjects.

But there has to be a better option available. It is a bit like the idea of peeing on your foot to relieve a jellyfish sting.

Somehow, this story evolved to the point where people assumed this was the number one thing to do in that situation. It isn’t. It doesn’t hurt, but seawater is much better.

To summarize, there really is nothing to worry about when it comes to urine fire risks. Your urine isn’t going to catch fire, no matter where you pee, how dehydrated you are, or how much alcohol you drink.

You can indeed use a bottle of it to start a fire in an emergency, but there are more pleasant options available. The same is true for putting out fires or treating burns. Only use urine when you have no other option.