Is WD40 Flammable? The Burning Question

When it comes to household items, there are a lot of questions that can come up regarding their safety and proper use.

One common product many people have in their homes is WD40, a multi-use spray that can help with everything from rust prevention to squeaky hinges.

However, there’s often some confusion around whether or not WD40 is flammable. This article examines this question and explore what you need to know to safely and effectively use the product.

What Is WD40?

WD-40 is a popular multi-purpose product known for its versatility in various applications. WD-40 stands for “Water Displacement, 40th Formula.”

It was initially developed by the Rocket Chemical Company in 1953 to prevent corrosion and displacing water from electrical components in the aerospace industry.

Over time, its uses expanded beyond its original purpose, becoming a household name.

WD-40 is a light, petroleum-based lubricant, and penetrating oil. It is formulated with various chemicals, including a solvent, lubricating oil, and anti-corrosion additives.

The exact composition is proprietary information held by the manufacturer.

Is WD40 Flammable?

The short answer is yes. WD-40 is a petroleum-based product that contains hydrocarbons that can ignite easily. This means that if WD-40 is exposed to heat or a flame, it can catch fire and cause a dangerous situation.

However, it is important to note that WD-40 is not classified as a highly flammable substance. It is considered to be a moderate fire hazard.

Is WD40 Flammable?

WD-40 has a relatively high ignition point, requiring a higher temperature or spark to ignite than other highly flammable liquids like gasoline or alcohol.

This also means that WD-40 is less likely to explode or cause massive fires.

Are WD-40 Fumes Flammable?

The short answer is yes, WD-40 fumes are flammable. WD-40 comprises a mixture of chemicals, including petroleum distillates, which are highly flammable.

When sprayed, WD-40 can create a mist of tiny droplets that can ignite if exposed to an open flame or spark.

This is why using WD-40 in a well-ventilated area and away from potential ignition sources is always important.

However, it is important to note that the flash point of WD-40 is relatively high, meaning that it takes a certain amount of heat to ignite the fumes.

The flash point of WD-40 is around 138 degrees Fahrenheit (59 degrees Celsius), which is higher than many other common household chemicals.

This means that it is unlikely that WD-40 fumes will ignite spontaneously in normal use.

Is WD40 Flammable After It Dries

The short answer is yes, WD40 is flammable after it dries. WD40 is highly flammable and should be kept from heat, sparks, flames, and other ignition sources.

The reason for this is that WD40 is made up of various chemicals, including petroleum distillates and propane. These highly volatile chemicals can easily catch fire if exposed to heat or a spark.

However, it’s important to note that the flammability of WD40 depends on several factors, such as the amount of WD40 applied, the surface it’s applied to, and the conditions in which it’s applied.

For example, applying too much WD40 to a surface can create a pool of liquid that’s more likely to catch fire. Similarly, if you apply WD40 to a hot surface, it can vaporize quickly and ignite.

Is WD40 Explosive

No, WD-40 is not considered to be an explosive substance. WD-40 is a flammable product, meaning it can catch fire and burn under certain conditions, but it is not explosive.

According to the United Nations transportation regulations, WD-40 is classified as a Class 3 flammable liquid.

It has a relatively low flash point, which is the temperature at which it can release vapors that ignite in an open flame or spark.

Therefore, it should be used and stored cautiously, away from open flames, sparks, or ignition sources.

While WD-40 is flammable, it does not possess the characteristics of an explosive material, which would involve rapid combustion, release of significant energy, and potential for detonation.

However, following proper safety precautions when handling flammable substances, including WD-40, is always important to minimize the risk of accidents or fire hazards.

Is WD40 Toxic

The short answer is no. WD-40 is not toxic to humans. WD-40 contains a mixture of lubricants, solvents, and other ingredients considered low in toxicity.

Small amounts of WD-40 may cause minor gastrointestinal irritation, but it is not considered a significant health risk.

However, it is important to keep WD-40 out of children’s reach and use it in well-ventilated areas to avoid inhaling the fumes.

Toxic To Animals?

While WD-40 is not considered highly toxic to animals, it can still be harmful if ingested in large amounts.

The solvents in WD-40 can cause gastrointestinal irritation, and the propellants can cause respiratory distress if inhaled.

Pets and other animals that accidentally ingest or inhale WD-40 should be taken to a veterinarian immediately.

Toxic To Plants?

WD-40 is not toxic to plants in small amounts, but it can be harmful if sprayed directly on foliage or flowers.

The solvents in WD-40 can cause the plant’s cells to break down, leading to leaf discoloration and even death.

If you need to use WD-40 near plants, it is best to cover them with a protective barrier or use a different type of lubricant.

Toxic To The Environment?

WD-40 is not considered highly toxic to the environment but can still negatively impact if not used responsibly.

The propellants in WD-40 are classified as volatile organic compounds (VOCs), which can contribute to air pollution if released into the atmosphere.

Additionally, WD-40 can harm aquatic life if it contaminates bodies of water. To reduce the environmental impact of using WD-40, it is important to use it sparingly and dispose of it properly.

At What Temperature WD-40 Ignite

WD-40 has a relatively low flash point, the temperature at which it can release vapors that ignite when exposed to an open flame or spark.

The flash point of WD-40 is typically around 120 to 145 degrees Fahrenheit (49 to 63 degrees Celsius).

It’s important to note that the flash point can vary slightly depending on the specific formulation and any additives or propellants present in the product.

Other factors, such as airflow, vapors’ concentration, and an ignition source’s presence, can also influence the ignition temperature.

Keeping WD-40 away from open flames, sparks, and high-temperature environments is recommended to ensure safe handling and usage.

Store it in a cool, well-ventilated area, and follow the manufacturer’s instructions and safety guidelines on the product label.

Will WD40 Catch Fire On Exhaust

WD-40 is flammable, and if it comes into contact with a hot surface, such as an exhaust system, it can ignite.

Therefore, it is important to exercise caution and avoid spraying WD-40 directly onto a hot exhaust system or any other hot surfaces.

A vehicle’s exhaust system can reach high temperatures during operation, especially after the engine has been running for a while.

If WD-40 is sprayed onto a hot exhaust system, the heat can vaporize the volatile components in WD-40, leading to the potential for ignition and a fire hazard.

To prevent accidents or fire, it is advisable to apply WD-40 to a cool exhaust system or allow the system to cool down before applying the product.

If you need to work with the exhaust system, it’s best to follow the manufacturer’s recommendations or consult a professional mechanic for appropriate procedures and safety precautions.

Does WD40 Evaporate

Yes, WD-40 can evaporate. WD-40 is a mixture of various chemicals, including solvents, lubricating oils, and additives.

The solvent component in WD-40 is responsible for its ability to penetrate and dissolve substances and evaporates relatively quickly.

When WD-40 is applied to a surface, the solvent portion of the formula starts to evaporate, leaving behind a thin film of lubricating oil and any additives present in the product.

The evaporation rate can depend on factors such as temperature, airflow, and the surface the WD-40 is applied to.

The lubricating oil and additives in WD-40 do not evaporate as readily as the solvents. They are designed to remain on the surface, providing lubrication and protection against corrosion.

However, the lubricating oil component may degrade or be removed over time through wear or exposure to external elements.

It’s important to note that the specific evaporation rate of WD-40 can vary based on formulation and environmental conditions.

In general, the solvent portion of WD-40 evaporates relatively quickly, while the lubricating oil and additives can provide longer-lasting protection.

Uses Of WD40

WD-40 is a versatile product with numerous practical uses. Here are some common applications of WD-40:

Lubrication: WD-40 can lubricate various moving parts, such as hinges, locks, door mechanisms, bicycle chains, and garage door tracks.

It helps reduce friction, prevents squeaking, and keeps mechanisms running smoothly.

Rust prevention and removal: WD-40 effectively prevents rust and corrosion on metal surfaces.

It can be applied to tools, outdoor furniture, car parts, and other metal objects to protect them from moisture and oxidation. It can also help loosen rusted bolts and screws.

Loosening stuck parts: WD-40 can be used to loosen tight or stuck parts, such as rusted nuts, bolts, hinges, and zippers. Its penetrating properties help break down corrosion and facilitate easier movement.

Removing adhesives and residues: WD-40 can dissolve and remove adhesives, stickers, labels, and sticky residues left behind by tape or glue. It can also be used to clean off crayon marks, tar, and ink stains.

Protecting and restoring surfaces: WD-40 can protect and restore surfaces such as vinyl, plastic, and rubber.

It can help maintain the appearance and flexibility of items like car dashboards, garden furniture, and rubber seals.

Displacing moisture: WD-40 is useful for displacing moisture from electrical connections, circuit boards, and ignition systems. It helps prevent electrical malfunctions caused by moisture or water accumulation.

Cleaning and degreasing: WD-40 can be used to remove grease, grime, and dirt from surfaces. It can be applied to tools, engines, and machinery to degrease and remove stubborn residues.

Preventing squeaks and noises: WD-40 can eliminate squeaks and reduce noise from hinges, doors, windows, and other moving parts.

Can You Spray WD-40 On Circuit Boards?

While WD-40 is often used for various purposes, spraying it directly onto circuit boards or electronic components is generally not recommended.

WD-40 is primarily designed as a lubricant, penetrating oil, and rust inhibitor, and it contains solvents that can damage sensitive electronic parts or leave behind residue that could interfere with the proper functioning of circuitry.

Electronic circuit boards and components require specific care and cleaning methods.

If you need to clean a circuit board, using specialized electronic contact cleaners specifically designed for this purpose is best.

These cleaners are formulated to evaporate quickly, leaving no residue, and are safe for use on electronic components.

When Should You Not Use WD-40?

On Electronic Devices: While WD-40 may be a great solution for lubricating mechanical parts, it should never be used on electronic devices.

The oil in WD-40 can damage sensitive electronic components, causing them to malfunction or even fail altogether.

If you have a problem with an electronic device, such as a smartphone or computer, it’s best to take it to a professional repair shop rather than trying to fix it yourself with WD-40.

On Bicycle Chains: Many people use WD-40 to lubricate their bicycle chains, but this is not recommended.

While WD-40 can help to clean off dirt and grime, it is not a suitable lubricant for bicycle chains.

This is because the oil in WD-40 is not thick enough to provide adequate lubrication for the chain, leading to increased wear and tear and even chain failure.

Instead, use a proper bicycle chain lubricant to keep your bike running smoothly.

On Locks: Although WD-40 is often used to lubricate locks, it’s not always the best option.

While it can help to free up a stuck lock, the oil in WD-40 can attract dirt and debris, which can actually make the lock harder to turn over time.

Additionally, the oil can gum up the works of the lock, making it harder to open and close. If you have a lock that’s giving you trouble, consider using a graphite lubricant instead.

On Food Preparation Surfaces: WD-40 is unsafe for food preparation surfaces. The oil in WD-40 is not food-grade, which could contaminate your food and make you sick.

If you need to clean a food preparation surface, use a non-toxic cleaner specifically formulated.

On Painted Surfaces: If you have a painted surface that needs cleaning or lubrication, be cautious about using WD-40.

The oil in WD-40 can strip the paint from the surface, leaving you with an unsightly mess. To clean a painted surface, use a mild soap and water solution.

WD40 VS Lubricant Oil

The most significant difference between WD-40 and lubricant oil is their intended use. WD-40 is designed to be a multi-purpose lubricant that can be used for a wide range of applications.

It is not specifically designed for use in engines or heavy machinery.

Lubricant oil, on the other hand, is specifically designed to reduce friction in engines and other machinery.

Another significant difference between WD-40 and lubricant oil is their viscosity. WD-40 is a thin, low-viscosity lubricant designed to penetrate and lubricate moving parts.

Lubricant oil, on the other hand, is available in various viscosities, ranging from thin to thick. The viscosity of lubricant oil is determined by its intended use and the requirements of the machinery it is being used in.

When to Use WD-40

WD-40 is ideal for small household items like door hinges, locks, and garden tools. It is also useful for removing rust and other types of corrosion from metal surfaces.

WD-40 should not be used as a lubricant for heavy machinery or engines, as it is not designed for this purpose.

When to Use Lubricant Oil

Lubricant oil is ideal for engines, transmissions, and other heavy machinery with high friction.

It reduces friction and protects moving parts from wear and tear. Lubricant oil is available in various viscosities, so choosing the right type of oil for your specific machinery and application is essential.

Safety Precautions Of WD40

When using WD-40, it is important to follow certain safety precautions to ensure safe handling and minimize the risk of accidents. Here are some safety tips for using WD-40:

Read and follow the instructions: Before using WD-40, carefully read the product label and follow the instructions provided by the manufacturer.

Pay attention to any warnings, precautions, or specific application guidelines.

Use in well-ventilated areas: When applying WD-40, ensure you are in a well-ventilated space.

The product may release fumes that could be irritating or harmful if inhaled in excessive amounts. If working indoors, consider opening windows or using fans to improve ventilation.

Avoid contact with skin and eyes: WD-40 is a solvent-based product and may cause skin irritation or discomfort if it comes into prolonged contact.

It is recommended to wear gloves and protective eyewear when handling WD-40.

If accidental contact occurs, wash the affected area with soap and water. In case of eye contact, flush the eyes with water for several minutes and seek medical attention if irritation persists.

Keep away from heat and open flames: WD-40 is flammable and should be kept away from heat sources, sparks, and open flames.

Do not use or spray WD-40 near hot surfaces, including exhaust systems, engines, or electrical equipment in operation.

Store properly: When storing WD-40, keep the container tightly closed and in a cool, dry place. Avoid exposure to direct sunlight, excessive heat, or extreme cold, as these conditions can affect the product’s stability and performance.

Keep out of reach of children: WD-40 should be stored out of the reach of children and pets to prevent accidental ingestion or misuse.

Disposal: Dispose of WD-40 and empty containers by local regulations and guidelines. Do not pour WD-40 down drains or dispose of it in the environment.

While WD-40 has many practical uses, it may not be suitable for all applications. If you have specific concerns or questions about the safe use of WD-40 for a particular task, it is recommended to consult the manufacturer’s recommendations or seek professional advice.


WD-40 is considered flammable. It contains flammable components, including solvents, which can ignite when exposed to an open flame, sparks, or high heat.

While WD-40 is flammable, it is important to note that it is not explosive. It does not possess the characteristics of an explosive material, such as rapid combustion or significant energy release.

To ensure safe usage, it is crucial to handle WD-40 with care, follow the manufacturer’s instructions and safety guidelines, and take appropriate precautions.

This includes avoiding contact with open flames, sparks, or high-temperature surfaces, using it in well-ventilated areas, wearing protective gloves and eyewear, and storing it properly in a cool, dry place away from heat sources.

By following these safety measures, the risk of accidents or fire hazards associated with the flammability of WD-40 can be minimized.