Is Paint Thinner Flammable? Things You Should Know About Thinner Before Using

The frequent use of thinner, whenever it’s something related to paint or paint stain, has become a norm. We don’t even care about its’ proper storage or ever think- can thinner burn?

Due to some properties of thinner, it catches fire under certain conditions. And so, people even haven’t witnessed how dangerous it can be! But being caught on fire doesn’t necessarily mean flammable. So now, you may ask- is paint thinner flammable?

In short, paint thinner can burn but only under high temperatures. So, let’s make the fact clear – is thinner flammable or combustible. And on what basis are they tagged as either flammable or combustible substances?

Can Paint Thinner Catch Fire?

According to Occupational Safety and Health Association, any liquid having a flashpoint less than or equal to 199.4℉ is flammable. Paint thinner’s flashpoint is 104℉, so it’s flammable. Non-flammable liquids have higher flashpoints than 199.4℉

Ever heard of flashpoint?

It’s the temperature at which the liquid gives out enough vapor to cause ignition.

However, the flashpoint of thinner is not always 104℉. It varies between 73.4℉ and 140℉, depending on the brand and other conditions. As you can see, thinners don’t need extreme heating conditions to catch fire. This property of thinners makes them more dangerous.

Is the Combustion Continuous?

The combustion process will be continuous under the auto-ignition temperature. A temperature of 743℉ or 245℃ will ignite the chemical and result in burning for a long time.

And such incidents can happen even without any flame source or discernible spark. That’s why storing, and disposing of paint thinners are concerning issues.

Is Paint Thinner Flammable Even After It Dries?

Paint thinner doesn’t form any layer after drying. When thinner dries, it evaporates as it’s volatile. So, there is no possibility of catching fire anymore.

But instead of a diluted liquid state, thinner might be present in gaseous form. When you work in a closed room without any ventilation, there might be the presence of fumes. Those fumes are flammable as well and can catch fire.

That’s why you are always suggested to ensure proper ventilation of the work area.

How to Store Paint Thinner with Utmost Safety?

As thinners can burn up without any potential flame source, storage is something to worry about. We live in a different region with different climatic conditions where the temperature differs drastically. Once the solvent reaches the ignition point due to the surrounding temperature, it will catch fire on its own.

Beware of two things while choosing the storing container. One is the airtight lid, and the other is leakage. Fumes come out from the unsealed vessel. While leaking solvents over time makes the storage room flammable.

Paint thinners are categorized as category-3-flammable material, and having more than a small container needs a safety cabinet.

While household work doesn’t need much thinner at a time, if you are dealing with gallons of thinners, then you need extra measures. In a specific area, you can place at most 3 safety cabinets at a time. Each cabinet shouldn’t have more than 60 gallons of thinner.

How to Safely Dispose of Thinner?

Paint thinners are water-soluble and so can contaminate the water Even if you find it convenient, never pour it on the drain or throw it in the dustbin.

By the time you want to toss the can out, it should be dried empty. You can even dry it by putting a cleaning rag inside, which you will be cleaning later. Or else, exhaust the solvent by keeping it under a cool shady place for an hour.

Then close the lid and throw the vessel in the household trash.

Oily waste containers are made for flammable wastage. Use this vessel to dispose of thinners. You can find them while working at commercial sites. Later on, the waste management service provider will seal them airtight and dispose of them professionally.

Safety Tips for Avoiding Unwanted Accidents

Mixing with Another Solvent

Don’t mix thinner with anything you get. You don’t know which one will react.

Paint thinner is a volatile and active chemical that would react easily with any chemical. Technically, there is a both bad and purposefully good outcomes of mixing paint thinner with something else. But here we are talking about the bad sides.

Avoid mixing with anything other than paint as long as you don’t know which chemical will react with the paint thinner. You don’t know which chemical will end up increasing the temperature.

Safety Measures

Don’t even try to work without safety equipment. Many of you who are reading it consider using thinners without any mask or gloves, and that is disastrous. It might not react immediately but surely will. Some thinners are strong enough to cause immediate irritation.

Even the eyes need to be protected from toxic fumes.


You might get irritated watching this word in every chemical-related article. But it’s something no one can ever skip. Never work with volatile materials in a closed area as prolonged exposure to them is hazardous.

Even if it’s impossible to work outside, at least ensure an exhaust fan.

Away from Acid

The hydrocarbons present in the thinner are reactive and combustible. The reaction between thinner and acidic solvents will result in toxic gases. So, if you are nearer to any acidic substance or working with them, keep your thinners away.

Nitric acid, phosphoric acid, sulfonic acid, hydrochloric acid, carboxylic acid, and many similar kinds of acids react with thinners.

Avoid Eating in the Vicinity of Thinners

As thinners are all about volatile and gaseous reactions, they might get mixed with food as toxins and end up entering the blood. Something like this can cause irreparable damage to your digestive system.

Avoid eating in the same room where thinners are being used or stay a few meters away from the project. Don’t forget to have clean hands before you eat.

Avoid Combustible Stuff

Keep any flame source or combustible stuff away from thinners to avoid any unforeseen causalities. Once there was news of a man getting his house caught in a terrible fire. The reason was that he threw his cigar end in a thinner container.

Stop Using It As a Cleaning Solvent

Many of you use thinners as a cleaning solvent when it’s supposed to be used for thinning paint. Without any stain over your counter, floor, or wall, you are inviting problems by using thinners.

If you must use it, remember to wash with water at the end or be sure of zero flammable substance near those stuff till the thinner dries. Use soapy water to clean your skin and cloth.

Final Cleaning

After your job is done, never leave your hand, cloth, tool, or the stained place unclean. Final cleaning with soapy water and air drying should always be your packing up step.

A Better Option

There are eco-friendly paint thinners that are less flammable. You can go for them if you are not sure about safety.

Even though these manufactured items aren’t zero toxic and zero flammable, it helps a lot in managing if you have children and pet in your house.

Some recommended products are-

  • Eco Solve Paint Thinner
  • Real Milk Paint Citrus Thinner
  • Eco-House Extra Mild Citrus Thinner
  • Bioshield Citrus Thinner

Bioshield Citrus is known for its’ neutrality in pH value. Anyone having sensitive skin can consider using it.


Now you can tell – is paint thinner flammable or not? Even the non-flammable substance having higher flashpoints are combustible at higher temperatures.

The neat difference between flammable and combustible is that – flammable can easily catch fire under standard temperature. On the other hand, a combustible substance needs a higher temperature than normal to catch fire.

Usually, products come with a flammable sign, and all you need is a safety precaution and proper disposal.

FAQs Section

Is turpentine flammable?

According to Occupational Safety and Health Association, any liquid having a flashpoint less than or equal to 199.4℉ is flammable. Turpentine has a flashpoint of 35℃ or 95℉, which makes the solvent a flammable substance. Turpentine is more suspectable to fire than conventional paint thinner and hence needs precaution for use.

Is paint thinner explosive?

Technically, paint thinners are flammable, not explosive. But under certain circumstances like the gathering of tons of expired thinner gallons, mixing lots of thinner with a combustible solution, or extreme temperature in a closed area might result in an explosion. There are many reports and news regarding this issue.

Is gasoline more flammable than paint thinner?

Gasoline is also used as a type of paint thinner, which is not suggested, basically. Gasoline is even more toxic and flammable. As it evaporates even faster, you will need in large amount to cover a project.

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