So, Is WD-40 Flammable?

One of the most devastating and sadly one of the most common disasters that any person can experience is a house fire. House fires claim dozens of lives and cause hundreds of millions in damages each and every year.

lighting WD-40 with lighter
lighting WD-40 with lighter

Aside from the obvious threat to life and limb, if your house or other building burns down it will destroy everything inside. That means all your belongings- gone!

To better defend against house fires, you need to know what things you keep in your stash are fire hazards. Let’s look at that one all-purpose chemical that all preppers love, WD-40. Is WD-40 flammable?

Yes, WD-40 is highly flammable with a flash point of 122 °F (50 °C). It burns in liquid form and when dry, but is highly and ferociously combustible in aerosol form.

This isn’t much of a surprise considering that WD-40 is made from petroleum distillates, but a lot of people don’t know that WD-40 is so dangerous while it is actually being sprayed.

There’s a lot more you want to know if you want to use WD-40 safely, and it’s especially important if you’re keeping a large stockpile on hand. Keep reading and I’ll tell you everything you need to know…

Is WD-40 Combustible?

Yes, WD-40 could be considered combustible by the standards of the American Fire Safety Association, with a flash point of 122 °F (50 °C).

Does WD-40 Ignite at Any Temperature?

Yes, WD-40 will readily ignite at around 122° F, which is the flashpoint. This means that any sparks, open flames, or hot surfaces can potentially ignite WD-40.

Assuming it’s in liquid form, not actively being sprayed, it will burn readily but with a relatively low, cool flame. It’s still very dangerous, make no mistake, but is not a particularly ravenous source of fuel for a fire.

How volatile and flammable is WD40, when using it. A bit of an experiment

Does WD-40 React with High Temperature?

WD-40 does not have a specific auto ignition temperature, but it has a very low flash point as detailed above.

If it’s in a very hot environment, such as in a car, hot shed, or any other such location it will ignite with ease.

Warning: WD-40 Is Extremely Flammable and Can Combust in Aerosol Form!

The major fire hazard associated with WD-40 is it when it is in aerosol form.

The fine mist or spray of WD-40 increases the surface area relative to the volume and increases the ratio of oxygen in the mixture, meaning it will readily combust, and it does so with extreme speed.

Another factor is that the typical propellant of aerosol WD-40 is butane, itself extremely combustible. Just makes for a potentially deadly one-two punch that can lead to a rupturing of the can that it is being sprayed from.

However, this isn’t just a concern with factory-produced aerosol cans: Lots of people buy bulk WD-40 in liquid form and then add it to manually operated spray bottles and other such equipment.

These devices can still produce a highly combustible mist of a WD-40, so it isn’t just the propellant you are worried about!

Is WD-40 Flammable When Dry?

Yes, it is. Most users know that WD-40 tends to dry out to an oily film after it has been applied and left to sit for some time.

Film still contains the important and active ingredients of a WD-40, and all of them are petroleum distillates or hydrocarbons which are still highly flammable. Dry WD-40 can and will ignite just like liquid WD-40 will!

Will WD-40 Make a Fire Worse?

Yes, definitely! WD-40 is a serious fire and combustion hazard, and any quantity of it that is exposed to fire will definitely make it worse.

If WD-40 is in a pressurized spray can, that can will likely rupture quickly and potentially with fatal results.

The resulting liquid, or a non-pressurized container of WD-40 in a liquid form, can easily spread a fire quickly beyond its current confines making it control and extinguishing it even more difficult.

The greater the quantity of a WD-40 that is being threatened by a fire, the more severe the situation really is!

Is WD-40 Reactive with Other Substances?

No. WD-40 is considered non-reactive under normal circumstances according to the material safety data sheet for the product.

However, it can potentially react with strong oxidizers and generate heat, meaning that such a reaction could easily ignite any quantity of WD-40.

For this reason, you must take pains to keep it away from any heat sources, all sparks and open flames, any other potential source of ignition and strong oxidizing agents.

Aside from the obvious fire hazard, a reaction with any such oxidizer will also produce copious amounts of carbon monoxide and carbon dioxide which are serious inhalation hazard, especially in confined spaces.

How Should You Deal with WD-40 Exposed to Fire?

Dealing with a fire started by WD-40 or any ongoing fire that is threatening a large quantity of WD-40 is tricky due to its water-displacing properties.

You never want to use high-pressure water or over flooding the affected area with water because of the burning WD-40 will float on top of the water itself and then travel to another area, potentially igniting other materials! Talk about a major curveball…

Instead, you want to use water fog, a carbon dioxide extinguisher, a dry chemical extinguisher or an extinguishing foam which will break the cycle of the fire that is using the WD-40 as fuel.

You can use a common ABC-rated fire extinguisher for this, but be careful to not blast the burning WD-40, because if it doesn’t go out it, will reignite and continue to burn, potentially starting a secondary fire as described above.

Additionally, if you’re dealing with a large quantity of WD-40 know that the vapor is heavier than air, and may sink to drift along the floor or other surfaces where can easily ignite if it reaches another ignition source.

As detailed above concerning aerosol WD-40, this combustion tends to be extreme, and highly dangerous so be ready for that…

As always, when in doubt, evacuate yourself and your loved ones and call 911 to let the firefighters handle it!

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