<p>Yes, there is still a risk, as the hazard is in the oil; as the oil dries, it emits heat (an exothermic reaction) which, if it's in a pile of other flammable objects--such as other oily rags, papers, etc--can cause them to combust.</p>

<p>From the <a href="http://www.wetcanvas.com/forums/showthread.php?t=605220" rel="noreferrer">Wet Canvas forum</a> (the thread also contains some personal experiences with combusting rags):</p>

<blockquote>
  <p>Remember it is the <strong>linseed oil that heats slightly as it dries</strong> (oils dry via a slow combustion process) and if the heat is trapped fire is a possibility, especially combined with highly flammable substances such as solvent. Whether you use solvent or not, soak your oily rags/paper towels in water or spread them out to get air.</p>
</blockquote>

<p>And a <a href="https://www.mutualofenumclaw.com/thinkitthrough/blog-post-page/home-blog-posts/2015/07/14/your-used-paint-rags-could-cause-dangerous-fires.-here-s-why" rel="noreferrer">blog from Mutual of Enumclaw</a> gives an additional citation to rags with oil-based paint on them being a hazard (as well as tips for handling them):</p>

<blockquote>
  <p>Simply put, rags that contain <strong>residue of oil-based paints and stains</strong>, paint thinners, varnishes, or polyurethane can spontaneously combust and catch on fire. Here’s what happens: <strong>When oily rags begin to dry, they produce heat.</strong> Combined with oxygen they turn into combustible cloths that can quickly cause trouble.</p>
</blockquote>

<p>(All emphasis above is mine.)</p>

<p>It is clear that the oil is the risk, and as the paints "straight from the tube" contain oil, it is best to treat them as a risk as much as you would the other items.</p>

CC BY-SA 4.0
2020-03-28T11:22:02.153Z
Thank you for these resources. I also checked the composition of the particular colors I have and the binder is in fact linseed oil.
einar
CC BY-SA 4.0
2020-03-27T17:47:36.410Z
2020-03-27T18:50:08.657Z
2020-03-27T18:50:08.657Z
Allison C
<p>I think was a problem of long ago. Although it can still happen today, it is now much less common. The risks were more common in the past when someone like a professional painter would collect a large box of oily/solvent/paint soaked rags. Back before water based paints were so common, and before disposable paper towels were available for cleaning, and before various cleaning products were available. A can of solvent type liquid is no problem; the problem is a collection of rags where there is good oxygen access over a large surface area and the center of the pile is thermally insulated by the surface rags.</p>

CC BY-SA 4.0
2020-03-27T19:30:47.050Z
The references I found made it clear that this is clearly a modern issue, and that paper towels (and any other paper) are also risky, not just "rags."
Allison C
CC BY-SA 4.0
2020-03-28T20:26:45.397Z
Water-based paints precede oil-based paints.
Joachim
CC BY-SA 4.0
2020-03-29T15:19:48.733Z
Water base paint does not predated oil base unless you are calling white-wash ( lime in water ) a paint . Paint contains a pigment, a vehicle ( oil, water, alcohol, etc.) ,AND a resin/polymer.
blacksmith37
CC BY-SA 4.0
2020-03-29T17:08:59.573Z
I am referring to a modern technical definition of paint as ASTM would use. The Wiki definition is not good ; but they do call the resinpolymer a "binder or film former". No doubt people have been painting on rock with muddy water,etc, for many thousands of years.
blacksmith37
CC BY-SA 4.0
2020-04-12T09:40:18.633Z
There have been many binders before oil was used: beeswax, glue, (Arabic) gum, egg yolk (of course, the history off oil-based paints is still lacking, so this also has to be taken with a grain of salt). And I would consider 'white-wash' paint when used for drawing imagery that is to have a decorative, ceremonial, religious, or expressive function. Also, 'muddy water' is a little derogatory, since the paintings that survive us were drawn with intentionally pigmented substances, and great care and skill.
Joachim
CC BY-SA 4.0
2020-03-27T19:08:17.537Z
2020-03-28T20:26:20.543Z
2020-03-28T20:26:20.543Z
blacksmith37
<p>No the oil paint alone will not combust but if paint thinner or mineral spirits that the oil paint brushes are cleaned with can.</p>

CC BY-SA 4.0
2020-03-27T17:23:03.557Z
2020-03-27T17:23:03.557Z
Donna Greathouse
<p>It is clear from what I can google that rags soaked in linseed oil and similar must be taken special care of because they could catch fire while drying. Is this also the case for rags, etc., with oil colors straight out the tube?</p>

<painting><oil-paint><safety>
Proper disposal: Can oil colors spontaneously combust?
einar
# Proper disposal: Can oil colors spontaneously combust?

(Asked by: username_0 on 2020-03-27)

It is clear from what I can google that rags soaked in linseed oil and similar must be taken special care of because they could catch fire while drying. Is this also the case for rags, etc., with oil colors straight out the tube?

**Tags:** painting, oil-paint, safety


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## 3 answers

### Answer by username_1 on 2020-03-27. Score: 5 | Accepted answer

Yes, there is still a risk, as the hazard is in the oil; as the oil dries, it emits heat (an exothermic reaction) which, if it's in a pile of other flammable objects--such as other oily rags, papers, etc--can cause them to combust.

From the [Wet Canvas forum](http://www.wetcanvas.com/forums/showthread.php?t=605220) (the thread also contains some personal experiences with combusting rags):

> Remember it is the **linseed oil that heats slightly as it dries** (oils dry via a slow combustion process) and if the heat is trapped fire is a possibility, especially combined with highly flammable substances such as solvent. Whether you use solvent or not, soak your oily rags/paper towels in water or spread them out to get air.

And a [blog from Mutual of Enumclaw](https://www.mutualofenumclaw.com/thinkitthrough/blog-post-page/home-blog-posts/2015/07/14/your-used-paint-rags-could-cause-dangerous-fires.-here-s-why) gives an additional citation to rags with oil-based paint on them being a hazard (as well as tips for handling them):

> Simply put, rags that contain **residue of oil-based paints and stains**, paint thinners, varnishes, or polyurethane can spontaneously combust and catch on fire. Here’s what happens: **When oily rags begin to dry, they produce heat.** Combined with oxygen they turn into combustible cloths that can quickly cause trouble.

(All emphasis above is mine.)

It is clear that the oil is the risk, and as the paints "straight from the tube" contain oil, it is best to treat them as a risk as much as you would the other items.

> **Comments:**
> **username_0**: Thank you for these resources. I also checked the composition of the particular colors I have and the binder is in fact linseed oil.  

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### Answer by username_2 on 2020-03-27. Score: -1

I think was a problem of long ago. Although it can still happen today, it is now much less common. The risks were more common in the past when someone like a professional painter would collect a large box of oily/solvent/paint soaked rags. Back before water based paints were so common, and before disposable paper towels were available for cleaning, and before various cleaning products were available. A can of solvent type liquid is no problem; the problem is a collection of rags where there is good oxygen access over a large surface area and the center of the pile is thermally insulated by the surface rags.

> **Comments:**
> **username_1**: The references I found made it clear that this is clearly a modern issue, and that paper towels (and any other paper) are also risky, not just "rags."  
> **username_3**: Water-based paints precede oil-based paints.  
> **username_2**: Water base paint does not predated oil base unless you are calling white-wash ( lime in water ) a paint . Paint contains a pigment, a vehicle ( oil, water, alcohol, etc.) ,AND a resin/polymer.  
> **username_2**: I am referring to a modern technical definition of paint as ASTM would use. The Wiki definition is not good ; but they do call the resinpolymer a "binder or film former". No doubt people have been painting on rock with muddy water,etc, for many thousands of years.  
> **username_3**: There have been many binders before oil was used: beeswax, glue, (Arabic) gum, egg yolk (of course, the history off oil-based paints is still lacking, so this also has to be taken with a grain of salt). And I would consider 'white-wash' paint when used for drawing imagery that is to have a decorative, ceremonial, religious, or expressive function. Also, 'muddy water' is a little derogatory, since the paintings that survive us were drawn with intentionally pigmented substances, and great care and skill.  

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### Answer by username_4 on 2020-03-27. Score: -3

No the oil paint alone will not combust but if paint thinner or mineral spirits that the oil paint brushes are cleaned with can.


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