Are watercolor paints toxic?

After seeing some information about nontoxic alternatives to the common color Cadmium Red, I began to wonder: are watercolors toxic? Should I be concerned?

tl;dr not really.

How to find hazard information

Paint Tubes

Most paint tubes from major brands feature a seal from the Art & Creative Materials Institute (ACMI), which rates paints as either “AP” (approved) or “CL” (cautionary labeling). AP paints are considered nontoxic. CL paints have known health hazards, and are to be kept out of reach of children under 11. I found these seals on my tubes of Daniel Smith, Holbein, M. Graham, Mijello Mission Gold, Mijello Mission Gold, and Winsor & Newton.

Daniel Smith tubes featuring ACMI seals on the back; the left is an example of AP and the right is an example of CL (on Rich Green Gold PY129).

Anything sold in California (which includes paint made abroad) is also required to have a warning under California’s Proposition 65 about any “significant exposures to chemicals that cause cancer, birth defects or other reproductive harm.”

This tube of Da Vinci Cobalt Blue has a Prop 65 warning about Cobalt, but none of my tubes of Da Vinci featured any ACMI seal.

For paints without the ACMI seal (for me, this included Da Vinci and Schmincke), look for the words “Conforms to ASTM-D 4236.” ASTM stands for the American Society for Testing and Materials; they set labelling standards for various substances. ASTM-D 4236 is the rule that requires art supplies to clearly label any ingredients that could pose a chronic health hazard. The label “Conforms to ASTM-D 4236” doesn’t necessarily mean that a paint is non-toxic; rather, it means that it has been tested by a toxicologist and that if any toxic ingredients are present, they are labelled.

In theory, if a paint tube conforms to the ASTM-D 4236 standard, and no hazards are listed elsewhere on the tube, there aren’t any. That said, sometimes you have to look closely – the hazard warning may not be right next to the ASTM notice.

I had to unwrap this tube of Schmincke Cobalt Turquoise to find the “U.S. Remarks” on this inside of the label for the Prop 65 warning for Cobalt.

Note: There are other ASTM standards that apply to watercolor, including ASTM-D 4303 (lightfastness) and ASTM-D 5067 (quality of watercolor paints). These latter two specifications are also good to have for other reasons, but they don’t include anything about toxicity, so look for ASTM-D 4236 to be called out as well if you’re concerned about safety standards.

Material Safety Data Sheets (MSDS or SDS)

Every paint company publishes safety data sheets, where it lists which of its colors contain potentially hazardous ingredients. You can find these on the paint company’s website, or on the websites for retail stores that sell them (e.g. Blick has a collection).

Here are some examples:

Online Databases

I use to get toxicity information for paints and prospective paints. They also list lightfastness and other notes. They rank paints on a A-D grade scale as follows:

A = Low hazard, but do not handle carelessly; Do not ingest; Avoid dust & spray.
B = Possible hazard if carelessly handled, ingested in large amounts or over long periods of time; Do not ingest; Avoid dust & spray.
C = Hazardous, use appropriate precautions for handling toxic substances, especially if working with the dry powder; Do not ingest; Avoid dust & spray.
D = Extremely Toxic

Below, I’ll give a rundown of which common paints get B and C grades. (D grade is not available in any commercial paint and is reserved for historic pigments, such as realgar, which was made from arsenic.)

Should I avoid paints with cautionary labeling?

Cautionary labeling means just that, “handle with caution,” not necessarily “don’t use.” Many paints with warning labels are in common usage. The hazardous materials are generally present in miniscule amounts, and you’d usually have to ingest them in large quantities to feel ill effects. Simply handling them or inhaling paint fumes (which are pretty nonexistent in watercolor) is unlikely to be a problem, though some paints may cause contact dermatitis for people who are sensitive to them (e.g. touching wet nickel-based paints may cause a rash if you have a nickel allergy).

If you go into making your own paints from scratch, you will have to think more carefully about inhalant dangers (since you’re handling raw powders). Users of paint won’t inhale powder from pigment suspended in paint, though.

Some people worry about long-term exposure or underreported dangers (toxic paints is sort of a theme in history, after all), and if it feels nicer to you to accumulate a palette of AP/A-rated paints, go for it! Avoidance is not the only tactic, however; if you love your Cadmiums and Cobalts, go ahead and use them with sensible precautions.

Sensible Precautions

Use these precautions with all paints, even those rated A/non-toxic.

  1. Keep potentially hazardous paints out of reach of pets or children.
  2. Don’t put your paintbrush in your mouth. Even to think.
  3. Don’t eat off the same dishes you use for paint. If you use an old plate as a paint palette, make it your dedicated paint plate, and don’t eat off it anymore. Wash it separately from your eating dishes.
  4. Don’t eat while you paint. Drinking water from a bottle should be fine as long as you don’t touch the spout with your painty hands. Drinking tea is common, but maybe not ideal, and if you ever accidentally dip your brush in your tea instead of your dirty water, that is IT. Do not drink it. Obviously. I hope. (If you go the other way around and accidentally sip your paint water… don’t panic, it’s probably fine. Just don’t like make a habit of it.)
  5. Avoid getting paint in your eyes. If you splatter vigorously, consider wearing glasses or blocking the spray from your face with paper. Don’t splatter near an open drink.
  6. Mind your toothbrush. When disposing of your water in the kitchen or bathroom sink, move your oral hygiene items/dinner dishes out of the blast zone.
  7. Wash your hands after you paint. I mean wash your hands after you do anything, really, but especially between painting and eating.

Disposing of Wastewater

Every municipality I’m aware of considers it acceptable to dispose of dirty watercolor water by tipping it down the sink, since it contains minerals and metals in such small amounts; it’s no more toxic than greywater from the laundry machine.

Alternately, you can use it to water your flowers. The minerals found in paints are also found in the soil and may be nutritious, or just non-issues for your plants.

If you are doing plein air painting in a protected wild/Leave No Trace area, pack out your water in a sealed container as you would with food/drink or anything else. To minimize your water use and prolong its cleanliness, use your cloth as much as possible to wipe your paintbrush and only rinse with a relatively clean brush.

What ingredients should I be aware of?


The most popular watercolor binders are nontoxic (gum arabic, guar gum, honey, etc.), so typically any toxicity would only be from the pigments. Therefore it’ll vary from one color to another, more so than brand.

Exception: When looking at Schmincke Horadam tubes, I found that all their paints warn about isothiazolinones. I looked this up, and it’s a preservative in the binder that may cause contact dermatitis (itchiness) in allergic individuals.


Pigment toxicity usually comes from heavy metals like cadmium, cobalt, copper, nickel, manganese, titanium, and zinc. Usually the metal name will be in the name of the paint, e.g. “Cadmium Red.”

Note that if the word “hue” is used in the color name, that means that the toxic metal named isn’t actually in the paint. Think of “hue” as meaning “color of.” so “Cadmium Red Hue” doesn’t actually contain the cadmium red pigment – it’s a paint the same color as a traditional Cadmium Red, but without the cadmium.

Here are some common metals that give paints a “CL” rating under ACMI and/or a Prop 65 warning, and the colors that contain them. This is not an exhaustive list of all potentially toxic watercolor pigments, but it does contain all the single-pigment colors with warnings that I found in the Daniel Smith and Schmincke SDS.

Mixes made from these colors are not specifically called out, but will generally also have the same issues. Additionally, he colors may go by different names in different brands, so it’s best to go by the pigment numbers.

C Grade


ACMI Label: CL
Prop 65 Warning: Yes
Art is Creation Grade: C

Cadmium is generally the metal of greatest concern to watercolorists. It is a known carcinogen if ingested, and may cause lung damage if inhaled (e.g. when making paints from powder).

Some companies, like Daniel Smith, have discontinued making cadmium colors (their Cadmium Red/Yellow/Orange Hues do not contain cadmium). But, many companies still offer them. Winsor & Newton explains on their website, “Cadmium itself is a heavy metal and is toxic but cadmium pigments are not classified as dangerous for use in line with EC classification. The level of soluble cadmium in the pigments is so low that no hazard warnings are needed and they pose no greater risk after swallowing or breathing in than other pigment types.” However, they offer cadmium-free alternatives for each of their cadmium colors.

Cadmium-Containing PigmentNontoxic Alternative
Cadmium Yellow Light/ Lemon (PY35)Hansa Yellow Light (PY3), Lemon Yellow (PY175)
Cadmium Yellow (PY35 or PY37)Hansa Yellow Medium (PY97), Pure Yellow (PY154)
Cadmium Yellow Deep (PY35 or PY37)Hansa Yellow Deep (PY65), Isoindolinone Yellow Deep (PY110)
Cadmium Orange (PO20)Pyrrol Orange (PO73)
Cadmium Red (PR108 or PR113)Pyrrol Scarlet (PR255), Pyrrol Red (PR254)

B Grade


ACMI Label: CL
Prop 65 Warning: Yes
Art is Creation Grade: B

Carcinogen if ingested. Some people are sensitive to cobalt, which can lead to asthma-like symptoms and/or skin hives.

Cobalt-Containing PigmentNontoxic Alternative
Aureolin/Cobalt Yellow (PY40)Quinophthalone Yellow (PY138), Azo Yellow (PY151), Holbein Aureolin Hue (mix of Pure Yellow (PY154), Lemon Yellow (PY175), Nickel Azo Yellow (PY150))
Cobalt Blue (PB28)Ultramarine Blue (PB29), especially light/”Green Shade” varieties (in my opinion the most similar is Winsor & Newton’s Ultramarine Green Shade)
Cobalt Blue Deep (PY74)Ultramarine Blue (PB29), especially deep/”French” varieties
Cerulean Blue (PB35 or PB36)Nothing is terribly like this. Most commercial Cerulean Hues are Phthalo Blue and white, but I don’t think it’s that similar.
Cobalt Turquoise/Teal (PG50)Nothing is terribly like this. Most commercial Cobalt Turquoise Hues are Phthalo Blue, Phthalo Green, and white, but I don’t think it’s that similar.


ACMI Label: CL
Prop 65 Warning: Yes
Art is Creation Grade: B

Copper is a heavy metal that can be hazardous if swallowed or inhaled (e.g. when making your own paints).

Copper-Containing PaintNontoxic Alternatives
Rich Green Gold (PY129)Rich Green Gold is most similar to Nickel Azo Yellow, which doesn’t help you since it will appear further down this list. Both colors have a glazey glow that is hard to get in another paint. Most effective hues, such as Daniel Smith’s Green Gold, contain Nickel Azo Yellow as well. You could mix a transparent green-yellow by adding a touch of Phthalo Green to your favorite nontoxic transparent yellow.

RGG’s typical mixing purpose is as a muted transparent yellow in mixing greens; Raw Sienna or a warm yellow (such as Hansa Yellow Deep) will also do that job.


ACMI Label: CL
Prop 65 Warning: Yes
Art is Creation Grade: B

Overexposure can lead to a neurological disorder called manganism that has been known to occur in ceramicists. I’m not aware of any cases involving watercolor.

Manganese-Containing PaintNontoxic Alternative
Manganese Blue (PB33)Most similar to Cerulean Genuine, which doesn’t help if you’re avoiding Cobalt. Phthalo Blue is typically the chosen alternative. Manganese Blue is granulating, so you may want to choose something like DS Manganese Hue which granulates the Phthalo Blue.
Manganese Violet (PV16)Ultramarine Violet (PV15) has similar properties (granulating, low tinting strength) though is usually much bluer. Quin Violet (PV19) has a more similar hue but extremely different properties (smooth, high tinting strength.)


ACMI Label: CL or AP (my DS Nickel Azo Yellow says CL, my Mission Gold version says AP, and DS Quin Gold says AP. Depends on concentration of nickel, maybe?)
Prop 65 Warning: Yes
Art is Creation Grade: B

Like copper, nickel is a metal that many of us are familiar with and that is found in many metal objects. Some people have a nickel allergy and handling nickel can lead to an itch or rash. (You may have gotten it before from jewelry or piercings.)

About Nickel, writes,

Some regulatory agencies (California) require a warning on paints containing the heavy metal nickel. Nickel can be toxic if ingested in large amounts over many years, but unless you are eating your paint, spraying it, or creating dust clouds with the dry powdered pigment, there is very little hazard, Just use common sense.

Nickel can cause skin sensitization and allergies in some people.

Avoid Dust & Spray;

Avoid excessive skin contact;

Do not ingest.
Nickel-Containing PaintNontoxic Alternative
Nickel Azo Yellow (PY150) This is a tough one to avoid because nothing else is really similar. It’s a yellow, but its combination of earthy/muted in masstone and glowing/bright in dilute is unusual. Also note this is an extremely common ingredient in premixed commercial colors (such as Quinacridone Gold and Sap Green).

Alternatives to the bright, transparent, green-toned dilute include Lemon Yellow (PY175), Azo Yellow (PY151), and Quinophthalone Yellow (PY138).

Alternatives to the earthy masstone include Yellow Ochre (PY42/PY43) and Raw Sienna (PBr7). Transparent versions may work best.

Also consider yellow/earth yellow mixes, such as Da Vinci’s Gold Ochre (PY83, PY42).
Nickel Titanate Yellow/Rutile Yellow/Titanium Yellow (PY53)Cool yellows such as Hansa Yellow Light (PY3), Lemon Yellow (PY175) may be similar in hue; mix with white for opacity and pastel quality. A slightly more muted color that matches opacity is Naples Yellow (PBr24).
Indian Yellow (PY153)Indian Yellow (PY83), Brilliant Hansa Yellow (PY74), Isoindolinone Yellow Deep (PY110), Isoindoline Yellow (PY139), Hansa Yellow Deep (PY65)

Note Schmincke doesn’t offer a single-pigment PY153, but several of its mixes contain PY153.

A with an asterisk

These paints are labelled “A” on, but are nonetheless called out in some safety data sheets.


ACMI Label: AP
Prop 65 Warning: No
Art is Creation Grade: A*

In their MSDS, Daniel Smith calls out Chromium as a potentially hazardous additive of Chromium Oxide Green (PG17) and Viridian (PG18).

Art is Creation writes of PG17, “if poorly manufactured, it may contain trace amounts of free chromium, a suspected carcinogen.”

And of PG18, “as a by-product of manufacture it may contain trace amounts of soluble Hexavalent Chromium, a suspected carcinogen, considered a known carcinogen in California, and may require a warning label. It should be safe in normal artist use, avoid dust, wear a mask working with the dry powdered pigment or spraying, limit exposure to skin & eyes or other mucus membranes, don’t eat it or point up your brushes with your mouth.”

Chromium-Containing Paint (maybe)Nontoxic Alternatives
Chromium Oxide Green (PG17)Various dull greens can be mixed from mixes of Phthalo Blue/Turquoise/Green and earth tones such as Yellow Ochre and Raw Sienna.
Viridian (PG18)Phthalo Green Blue Shade (PG7) has a similar hue but opposite properties (staining, high tint, smooth where Viridian is non-staining, low-tint, and granulating.)


ACMI Label: AP
Prop 65 Warning: Yes
Art is Creation Grade: A

Daniel Smith calls out Titanium White (PW6) and Buff Titanium (PW6:1) as requiring Prop 65 warnings for the metal titanium; Art is Creation doesn’t even merit this an asterisk. As a person who switched from nickel to titanium jewelry due to an allergy, I would sooner use this than Nickel Azo Yellow (and I still use Nickel Azo Yellow).


ACMI Label: CL
Prop 65 Warning: No
Art is Creation Grade: A

Daniel Smith calls out Chinese White (PW4) and Naples Yellow (mix with PW4) as containing zinc in their SDS, and evidently these also require a CL warning from ACMI, because zinc may be harmful if swallowed (which I can confirm as a person who once hurled after taking a zinc cold pill on an empty stomach).

Other Pigments

I chose to focus only on those with ACMI CL ratings and California Prop 65 warnings for this article. That may not be an exhaustive list of all substances that can irritate you. For nearly every pigment, even those labelled “AP”, I found an article describing them as an eye or skin irritant or carcinogen. And sometimes people are allergic to substances that are generally considered safe.

Where I Landed

It’s easy to get caught up in a purity mindset and want to cut out all potentially toxic paints… but due to the lack of concrete information and the general overcautiousness of the warnings, I think that would be a mistake. The warnings can sound scary, but it’s the dose that makes the poison. Many of these chemicals and minerals are found naturally in the earth and in our bodies in small amounts. (Manganese is an essential nutrient, etc.) If we stopped using tools made from every mineral, metal, or substance that could cause us harm if ingested in large amounts, we would not be able to use anything.

Still, some pigments are undeniably more concerning than others, and the reality is that I’m a messy painter. I’m known to splatter paint around, get paint on my hands and my stuff. Even when I try to be careful, Shit Happens. I’m not about to (intentionally) eat my paints, but I’d feel most comfortable choosing to use paints that I don’t worry about touching wet, or accidentally ingesting in trace amounts.

Everyone draws their own line with these things, but I wound up deciding no on the Cadmium paints, and yes on the others. This is what allows me to sleep at night, but it’s certainly an area where reasonable people can disagree.

I hope this has helped you to figure out your own line. Whatever you choose, handle your paints with a reasonable level of care, and enjoy them!