Is Acetone Flammable or Combustible?

Is acetone flammable or combustible? Acetone is a liquid chemical used in a dozen ways. But only a few can tell with certainty if acetone is flammable or not.

In this article, we’ll clear the air on that and on whether acetone-based products like nail polish removers can indeed become a fire hazard or not.

Is Acetone Flammable?

Acetone is extremely flammable. Even at room temperature, a jar of liquid acetone can light up in ways that you don’t even expect. As a gas, the fire hazard doubles up. 

So, keep it and anything made of acetone is far from an open fire source. And always remember that caution and care should be your number one priority when handling acetone and acetone-based products.

Considering that, acetone is often stored in an air-tight container kept in a dark and cool spot. This spot should be well-ventilated to avoid the dangerous build-up of toxic acetone fumes.

Likewise, the spot should be a place quite distant from electrical wirings. This is because even the slightest spark can ignite a bottle of acetone. And that’s how much of a hazard it is.

Why Is Acetone So Flammable?

One major reason acetone is flammable is that its flash point is -40F.

That means, at any temperature below that, even a static discharge can ignite acetone fumes. What’s worse, it will continue to burn even after you remove the ignition source.

Besides that, acetone is quite denser than air. That means acetone fumes often collect near the ground and around your feet rather than floating in the air.

Acetone vapor can travel across your house or room along the floor undetected to an ignition source. And then, kaboom!

Worse still, the burning flame can flash back to the original acetone jar to cause an even bigger explosion.

Now, this time, the closed acetone jar may shatter in all directions, and you know what that means if the jar is a glass container.

Pouring acetone over red-hot coal will not ignite it. This is because of a high concentration of vapor and the cooling effect of the evaporation of this liquid.

Acetone can also ignite itself at a temperature of 8690F. This phenomenon is called Auto-ignition. Although for acetone, it depends on how long you expose the liquid to heat.

​What Are the Common Ignition Sources for Acetone?

1. Naked flames
2. Electric spark
3. A static discharge
4. Heat
5. Long exposure of acetone container to sunlight
6. Any other ignition source out there.

Common Substances Used to Extinguish Acetone Fire

Like gasoline, acetone fire is not one you can kill with a stream of water. So, water should not even be considered an extinguishing media.

However, you can use water to cool air-tight and fire-exposed acetone containers. That said, let’s briefly list some substances that can actually help:

1. Carbon dioxide
2. Dry chemical powder
3. Fog or water spray
4. Alcohol-resistant Extinguishing foams.

What Class of Flammable is Acetone?

Acetone is classified as a Flammable Liquid Category-2, a category-3 organ toxicity agent, and a category-2 eye irritant.

Point in case; category-2 flammable liquids are those with flashpoints below 73.40F. Common examples of other category-2 flammable liquids include:

1. Benzene
2. Toluene
3. Ethanol
4. Cyclohexane
5. Carbon disulfide

In the US, the Environmental Protection Agency (EPA) does not classify Acetone as a volatile organic compound.

In the European Union, acetone is considered to be a pollution threat.

The reason is that when acetone burns, a lot of toxic gases break out.

Some of them include carbon monoxide which is very poisonous, carbon dioxide, flammable methanal, corrosive ethanoic acid, and other chemicals.

Read more: How Hot is Fire? – The temperature of fire

Where is Acetone Found?

In the science world, acetone is known as propanone, and it is a pretty common chemical.

It can be found in:

1. several beauty products like nail polish removers.
2. Plants and trees.
3. Forest fires
4. Volcanoes
5. Car exhausts
6. Landfills
7. Tobacco smoke
8. The human body, especially in people that follows a strict diet.

Is Acetone-free Nail Polish Remover Still Flammable?

Yes, the acetone in nail polish remover can catch fire, especially if a sufficient amount of it is vaporized.

However, the liquid acetone in nail polish remover doesn’t actually catch fire itself.

Rather, it emits vapor. These acetone fumes are flammable agents.

For that reason, you should not use your nail polish remover near naked flames, outlets, or any other place prone to electric sparks.

Likewise, you shouldn’t attempt to smoke cigarettes immediately after using nail polish removers.

Even after it is dry, the acetone in nail polish remover still poses some level of fire hazard. It only takes a few minutes for a nail polish remover to catch fire. So, extreme caution is needed.

To put things into practical perspective, you can watch this video to see how fast the nail polish river can start a fire.

Is Acetone Flammable When Mixed with Water and When Dry?

Acetone itself is liquid at room temperature. But this liquid is highly volatile.

So, when left alone over a prolonged period, it can compare vaporize completely to leaving behind a dry surface. This dry surface is non-flammable unless another flammable material makes up the surface.

However, the acetone is not gone. It lingers in the air as vapor. These acetone fumes are very flammable and as explained earlier, are denser than air.

As such, the fumes can travel undetected along the floor to an ignition source to cause an explosion. So, even a dry surface doesn’t avert an acetone fire hazard. Instead, it only makes the matter worse.

Even if you mix the acetone with water, the flammability only reduces. With the right condition, the acetone-water mix can still light up.

This is because a 4:96% acetone water still has a flash point of 54 °C. A potential explosion is still possible when the acetone vapor mixes with the air above the water surface.

Final Recommendations.

So far, we note that acetone is inflammable (extremely flammable and volatile). You should handle it with extreme caution.

In this article, we already mentioned some notable takeaways for storing acetone.

Here are some other things to note:

1. Acetone is best stored in-ground and in electrically bonded containers.
2. Always keep acetone jars away from heat and prolonged sunlight.
3. In the case of large storage, use large drums with pressure and vacuum reliefs.
4. You can even add a flame arrestor.

And with that, all should be good. If you also want to learn more about other flammable substances like alcohol and gasoline, click here.