Is Paint Thinner Flammable? (Answered)


Paint thinner is required to clean your paint brushes after completing significant projects around your house. Additionally, you can use it to thin out or clean up spilled paint. However, have you ever wondered whether paint thinner poses a fire risk? Is paint thinner, for instance, flammable?

In this article, we will provide an answer to that question. You’ll also learn the flashpoint of paint thinner,  if it’s flammable when dry or if it can catch fire easily. If you’ve ever questioned which gasoline or paint thinner is more flammable, keep reading. Finally, we clarify if paint thinner is toxic and give tips on properly disposing of it.

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Is Paint Thinner Flammable?

Paint thinner is flammable. Even at room temperature, it will quickly catch fire. Paint thinner is a petroleum-based substance. Hence there is a very high chance of an explosion. Non-flammable liquids can also ignite, but doing so requires higher temperatures. Flammable substances like paint thinner will catch fire without needing to be heated first. 

Because of this, you should never use it close to an open flame or other fire sources. There are various kinds of paint thinners, though. Petroleum distillate, natural resins, and natural and synthetic oils make up most of the ingredients in paint thinners used in oil paints. Water-based paint thinners, which may be less flammable, are used with water-based paints.

The most widely used paint thinners contain the dangerous elements listed below.

  • Turpentine
  • Acetone
  • Benzene
  • Methanol
  • Naphthalene
  • Xylene

Because they are all flammable on their own, the compounds above need to be handled carefully at all times.

What is the Flashpoint of Paint Thinner?

Paint thinner has a flashpoint of 104°F (40 °C). The temperature at which a liquid releases sufficient vapors to ignite when a flame is present is known as the flashpoint. 

The flash points of various paint thinners could also differ. Look at the various flash points listed in the table below.

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Type of paint thinnersFlash point
Lacquer thinner73°F(23 °C)
Mineral spirit140°F(60 °C)
Alcohol55.04°F(12.8 °C)
Turpentine95°F(35 °C)

According to OSHA (Occupational Safety and Health Association), a liquid is considered flammable if it has a flashpoint at or below 199.4°F(93 °C). 

Is Paint Thinner Flammable When Dry?

Dry paint thinner is not flammable. The majority of the flammable substances have evaporated. It’s important to remember that the paint’s thinner, flammable vapors can still be present.  It is risky to introduce an ignition source if the space you are working in is poorly ventilated. When using paint thinners, remember that they tend to evaporate easily. 

There is nothing left to ignite because every component has evaporated. What you cannot see will not burn. But the paint thinner is still flammable in its gaseous state.

Depending on the circumstances, paint thinner evaporates at a different rate. It will take some time for the paint thinner to evaporate after applying it to a surface. If paint thinner is put inside a container, the amount will determine how long it takes to evaporate. It can take several hours, days, or even weeks. However, whether the container is open or tightly sealed will also affect the evaporation rate.

Can Paint Thinner Catch on Fire Easily?

A paint thinner can easily catch fire. The fact that it is considered flammable means that even at low temperatures, paint thinner will catch fire easily. When exposed to oxygen, paint thinner catches fire faster. It can also self-ignite, so any rags that contain paint thinner should be properly disposed of. 

See how easily paint thinner catches fire:

It is strongly recommended that you keep open flames and sparks away from paint thinner while also refraining from smoking. Either turn off anything electric or make it all explosion-proof. Use non-sparking hand tools instead.

Its not only a flame that will cause paint thing to catch fire but high temperatures too. When you store tightly sealed containers in high temperature areas, the container is at risk of exploding or catching fire. 

Is Paint Thinner and More Flammable Than Gasoline?

More fires can start from gasoline than paint thinner. The flash point of gasoline is -45 °F (-42 °C), making it more flammable than paint thinner. It has a high vapor density and a very low flash point. Gasoline will catch fire from a spark, flame, or even static electricity in the area.

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The ratio of the density of vapor to the density of air is known as vapor density. Things that are heavier than air have vapor densities greater than one. The vapor density of gasoline is 3–4. That means gasoline is between three and four times heavier than air and can easily travel farther.

Heavier air vapors tend to collect in low or enclosed areas. It then becomes easier for the vapors to ignite faster. 

Is Paint Thinner Toxic?

Because they contain hazardous compounds, paint thinners are toxic. They have toxic, highly reactive hydrocarbons in them. The situation is significantly worse if the thinners come into contact with any acidic substance. There will be a hazardous reaction that releases poisonous fumes. After inhaling paint thinner repeatedly, you may experience headaches, nausea, dizziness, and difficulty breathing.

Prolonged inhalation will pose problems with the central nervous system, respiratory issues, and other chronic ailments. Because paint thinners contain volatile organic compounds, handling them should be done with caution.

Here are some safety measures you can take while using paint thinners.

  • Work in well-ventilated places to prevent the fumes from paint thinner from building up and endangering you as they are flammable. Use exhaust fans and leave the windows and doors open.
  • Wear protective clothing, goggles, and masks when working with paint thinner to protect yourself from the fumes.
  • Wash the affected skin area as soon as possible with soap and cold water.
  • But if the paint thinner gets into your eyes or you accidentally ingest it, see your doctor immediately.

How to Safely Dispose of Paint Thinner?

You should always ensure that the container with the paint thinner is tightly sealed to prevent leaks. Never pour it down the drain because it will contaminate groundwater. You should also avoid disposing of it in the garbage bin because it is highly flammable. What is the proper way to safely dispose of paint thinner?

You can do so by following the highlighted tips below:

  1. If you are working on a commercial site, you can put the paint thinner in oily waste that you can set aside for flammable waste. The waste can will then be disposed of by a professional waste management company. 
  2. You can put the paint-thinner container with the lid off in a shaded and cool outdoor location. Depending on the amount of paint thinner, an hour or so is enough for it to evaporate, and you can discard the container as household waste. 
  3. You can take the unused paint thinner and the soaked rags to a hazardous waste facility or a collection center. 
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Pour a little paint thinner on a paper towel to verify if it is still good for reuse. You can reuse the paint thinner if the paper towel turns yellow. You cannot reuse paper towels that have turned black or brown because they are contaminated.

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Frequently Asked Questions

What should you not use paint thinner with?

Don’t use paint thinners on dried brushes, as it is no longer effective. Paint thinners only work well when the paint is wet. However, acetone is strong enough to dissolve the dried paints. 

You should not use paint thinner for oil-based paints for shellac, lacquers and latex paints. 

How long do paint thinner fumes last?

If you left the windows and doors open, a few minutes. But its smell won’t go away fully until 36 to 48 hours have passed. However, it also depends on the components that go into making the paint thinner.

There are four ways you can mask the smell of paint thinner fumes for those 48 hours. 

1. Spread a few quartered onions throughout the space to absorb the paint thinner smell.
2. You can scatter freshly ground coffee beans throughout the room in bowls if you have them.
3. It can also be accomplished by scattering cotton balls soaked with peppermint oil or a few drops of vanilla extract around the room. Due to the powerful scents of both vanilla and peppermint, you can also add a few drops to small bowls of water.
4. You can crush wood charcoal before placing in containers and leave them overnight.


You can clean up more easily while painting thanks to the paint thinner. However, you should note that it’s flammable and can easily catch fire. It will self-ignite with a flash point of 104°F (40 °C). Ensure you don’t throw away the dried rags you put in the paint thinner since dry paint thinner is equally flammable.

Despite being less flammable than gasoline, paint thinner is nonetheless toxic. Dispose of the paint thinner responsibly by using the tips we have suggested to prevent putting yourself at risk.

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