Is WD-40 Flammable? – Know Before You Use!

WD-40 is one of the most popular multi-use products. That’s why it’s pretty much in every house. But have you ever wondered how safe it is around a fire?

That is, is WD-40 flammable?

WD-40 is a highly flammable aerosol. Moreover, these cans contain gas that’s stored under extreme pressure. So, if you heat it up, there’s a high chance that it will explode.

Now the question is, at what temperature does WD-40 ignite or explode? And where should you not use this product? Keep on reading to learn all the answers!

Is WD-40 Flammable

Understanding WD-40

Before understanding lubricating oil flammability for this specific product, you should know what it actually is. At the core, WD-40 is a lubricant and rust penetrant. It can also play a role in protecting metal from corrosion and rust.

Thanks to the unique formula of the liquid, WD-40 can even penetrate through stuck parts, displace moisture, and lubricate pretty much everything. So, in short, you can consider the product as a highly versatile household item.

Common Uses of WD-40

  • Protecting metal parts from rust and corrosion
  • Penetrating stuck parts and making them loose
  • Displacing moisture from tight and hard-to-access spaces
  • Lubricating almost anything
  • Cleaning metal parts
  • Removing stubborn stains from clothing items
  • Cleaning adhesive from different surfaces

Flammability of WD-40

Even though WD-40 comes in a spray form, its ignition characteristics are not the same as the flammability of spray paint. Nonetheless, WD-40 is extremely flammable. But the degree of flammability relies on the overall state of the product.

Is WD-40 flammable when heated?

WD-40 is flammable when it is under extreme heat. According to the Material Safety Data Sheet, WD-40 is an “Extremely Flammable Aerosol” and contains gas under pressure.

When a highly pressurized gas receives heat, the moles gain more energy, which makes them move faster. In addition, it expands. So, in short, WD-40 will explode when you heat it up.

But is WD-40 flammable when dry?

In terms of whether WD-40 is flammable after it dries, the answer would be yes. It contains petroleum distillates, which are flammable even after drying.

At What Temperature Does WD-40 Ignite/Burn?

The ignition temperature of liquid WD-40 is 47 degrees Celsius. In other words, in liquid form, the WD-40 will start to burn when the temperature reaches 116 degrees Fahrenheit.

Therefore, even if the object you spray at is not combustible, you need to consider that the product is. You will start a fire while spraying the WD-40 close to an open flame.

What Happens If You Heat WD-40?

The WD-40 will start to ignite and burn when heated up. It will also begin to produce toxic hydrocarbons when the temperature gets excessively high. These hydrocarbons react with nitrogen.

What Happens If You Heat WD-40

And the reaction between hydrocarbons and nitrogen creates ground-level ozone. It’s toxic to your health. So, the concern does not revolve around starting a fire. In addition, it’s also about exposing yourself to toxic fumes.

Where Should You Not Use WD-40?

Now that you have a fair idea about the flammability of WD-40 let’s talk about where you should not use WD-40. Take a look –

Near Open Flames

Check the surroundings when you are using the WD-40. Make sure that there are no open flames around.


It’s better not to use WD-40 on electronics. Not only will you damage the parts, but there’s a chance of creating a spark for short circuits. This spark will eventually start a fire.

Objects that Can Heat Up

As you know, the ignition temperature of liquid WD-40 is 47 degrees Celcius.

Also, dry WD-40 is flammable. So, you should not use the product on top of substances or objects that can excessively heat up on their own.

Medical Purposes

Although it’s not related to fire, you should not use it for medical purposes. After all, WD-40 contains toxic substances. The manufacturer does not even make any claims regarding this use case.

Painted Surfaces

Another thing that’s not related to flames but should be noted is painted surfaces. WD-40 can remove the paint layer after reacting with it. For that reason, you should avoid using it on treated surfaces.

Safety Considerations While Using WD-40

You should adhere to some safety precautions when you are using the WD-40. These will help you to get effective results without any consequences –

Keep Away from Heat, Open Flames, Sparks, and Hot Surfaces

At this point, this is a given fact that you should not use WD-40 near flames or sparks. In fact, do not even smoke while you are using the product. Also, ensure that the surface you spray it on does not heat up.

Use the Product While in a Well-Ventilated Area

You need to understand that WD-40 contains harmful substances. No matter what, it should not be inhaled. And to lower the chances of that happening, you should make sure that you are using it while being in a properly ventilated area.

Avoid Contact with Skin

According to WD-40, the product can cause moderate skin irritation with short-term exposure. It may even cause itching, burning, and redness on the skin. And with prolonged exposure, things can take a turn.

So, make sure that you do not let the product come in contact with your skin. Also, wear safety gear.

Store in a Proper Place

When not in use, store the WD-40 in a place where it is cool and dry. Make sure it is away from heat sources. And no matter what, you should not keep it near flames.

Dispose of Empty Containers Correctly

Aerosol empty or part-full cans should be thrown in a hazardous waste collection site. Your area should have a disposal facility. Check the local map if you cannot find one near you.

Frequently Asked Questions

1. What Is the Flash Point of WD-40?

The flash point or ignition temperature of WD-40 is 47 degrees Celsius, which is 116 degrees Fahrenheit.

2. Is Non-aerosol WD-40 Flammable?

Non-aerosol WD-40 is not flammable when it dries. But in the liquid state, even the non-aerosol version should be handled with precautions.

3. Can I Use WD-40 as a Fire Starter?

Although WD-40 is flammable, it’s not a reliable fire starter. To be exact, it’s dangerous to use it as a fire starter because you will not have control over the ignition.

Final Words

So, is WD-40 flammable? In short, it is! For that reason, you should be very careful while using it. You must also consider the fact that it is combustible once dried up.

And it goes without saying that the instructions on the label should be strictly followed.