Pertinent Tox Issues

Pertinent Tox Issues

The Duke Toxicology Program both evaluates risks associated with consumer product use and conducts studies to compliment or validate our risk assessment approach. Materials that are of regulatory concern are also evaluated by this program including lead and asbestos. Studies that have been conducted by this program include assessment of bioaccessibility of various metals found in art materials with skin or mouth contact; hand to mouth transfer of art materials; and solvent exposure during use of markers with solvent-based inks. 

Skin Sensitizers and Irritants

Quantitative Evaluation of Skin Sensitizers and Irritants

The 2017 paper “Protocol for Assessing Derman Exposures While Using Pressurized Aerosol Sprays, Airbrushing and Drawing with Pastels” uses a quantitative risk assessment approach for evaluating skin sensitizers and irritants for which human patch test results are available. Two examples of such an approach are the risk assessment for isothiazolinones and formaldehyde-releasing preservatives.

Quantitative Assessment of Skin Allergens

Acceptable levels of allergens have been determined by the percentage of the allergen that can be used without resulting in an allergic reaction. Human insult patch testing has shown that the risk of an allergic reaction is related to the amount of allergen that comes into contact with the skin surface. This approach to the quantitative assessment of allergens is detailed in the 2013 paper “Quantitative Risk Assessment of Skin Sensitizers and Irritants.”  

Benzoisothiazolinone Action Level

The action level for benzisothiazolinone, a preservative, has been decreased to 470 ppm in art materials based on human testing showing irritation and sensitization potential at higher levels.

Natural Rubber Latex

ACMI requires labeling for natural rubber latex sensitization hazards in all liquid products containing natural rubber latex and in artists’ rubber erasers containing natural rubber latex. Recent studies have shown extractable rubber latex antigen in this type of eraser. Studies are ongoing looking for extractable rubber latex antigen in erasers containing <10% natural rubber latex.

Lead in Consumer Products

Bioaccessibility Testing

A number of studies of lead-containing materials have been conducted to support the use of bioaccessibility testing as means for determining chronic risk from metals contained in ingested materials. The following papers summarize these studies. The 2017 research report “Comparison of the Solubility of Lead in Various Materials and Its Bioavailability” compares the results of feeding studies of lead-containing ores with bioaccessibility testing of these ores. A second paper, “Factors affecting the solubility of metals in art materials,” addresses a mass ion effect seen when there is an excess extractant volume is used for testing.

Ceramic Glaze Exposures

Guidelines for Safe Use of Ceramics

Read the proposed appendix to ASTM's D1023: Guidelines for the Safe Use of Ceramic Art Materials.

Boric Acid Risk Assessment

Soluble boron, in the form of boric acid, can cause acute brain damage and/or seizures with ingestion of large amounts over short periods of time. With chronic exposures there is a risk of fetal toxicity and testicular effects with decreased fertility. This risk assessment evaluates new knowledge on the toxicity of boron with a focus on chronic developmental and reproductive toxicity.


Manganese is a neurotoxin with a parkinsonian syndrome found in individuals exposed to high levels of fumes from ferromanganese ores. Neuropsychological changes can be found at lower exposures. Read a critical review of the literature.

Evaluation of Aerosol Sprays

Canada’s Consumer Chemical and Containers Regulations, 2001 specifies that products containing >10% low viscosity compounds (certain hydrocarbons, alcohols and ketones that present aspiration risks) must have child-resistant packaging except" a spray container that cannot be opened and that disperses the product as a mist." The report “A test methodology for determining aspiration hazards of aerosol sprays” describes the development of a test method to determine whether or not an aerosol spray is a mist and reports on tests of a wide variety of aerosol products.

Evaluation of Respirable Particle Exposures

Aerosol Exposures

The Duke Toxicology Program has completed a number of studies to measure aerosol production during various art and craft activities. The report “Aerosol Production During the Use of Art and Craft Materials” details these studies and uses them to model aerosol exposures associated with these activities.

Talc Dust Exposures

The above-mentioned studies are further summarized in a report to the Consumer Product Safety Commission on risks of talc exposure associated with art and craft activities.

Pastel Dust Exposures

The evaluation of dusts produced from the use and cleanup of art works made with pastels and chalk are discussed in the paper “Risk Assessment for Exposure to Respirable Dusts Generated from the Use of Chalks and Pastels.”

Testing for Spontaneous Combustion Risk

Rags soaked with linseed oil present a risk of spontaneous combustion. In the past two decades, a number of oils have been developed to substitute for or amend linseed oil, including safflower oil an walnut oil. ASTM has developed method D6801 to test for spontaneous combustion risk. This method was initially used to evaluate linseed oil-based products but now has been extended to the evaluation of a wide variety of oils and products, including those used in the art material field, wood refinishing and foods. Read a report of these expanded tests.


Soluble Copper Risk Assessment

  • Acute exposures to soluble copper have been associated with hemolysis of red blood cells and acute kidney failure while chronic exposures have been associated with cirrhosis of the liver. Copper can cause effects when inhaled. This copper risk assessment will be useful in determining acceptable levels of respirable copper and soluble copper in art and craft materials.
  • ATSDR has proposed a minimum risk level (MRL) for soluble copper based on a concentration-dependent effect, nausea. This comment recommends that a dose-related effect be used to determine copper’s MRL, liver toxicity.

Copper Dust

A report from the National Poison Control Center Network identified a death in a senior citizen who inhaled copper dust while working with a craft project at a day care center for senior citizens. ACMI’s Toxicology Advisory Board has reviewed this issue and agrees that brass or bronze powders should be tested for respirable size as a measure of risk of inhalation.

Titanium Dioxide

Titanium dioxide is a white pigment widely used in art materials. An assessment of the potential of exposures to titanium dioxide to be associated with a risk of lung tumors in man has been submitted to the California's Office of Environmental Health Hazard Assessment.

Phthalate Esters

The 2003 study “Determination of the Magnitude of Clay to Skin to Mouth Transfer of Phthalates Associated with the Use of Polymer Clays” investigates hand contamination when using polymer clay, both in the laboratory and by professional polymer clay artists, and addresses the potential for incidental ingestion of phthalate esters associated with hand contamination.

Risk Assessment for Phthalates in Polymer Clays

The National Toxicology Program (NTP) has completed a re-assessment of the hazards associated with exposure to some phthalate esters. Some of these phthalate esters are used as plasticizers in polymer clays, which are modeling clays that are heat set at a low temperature. ACMI's risk assessment of hazards associated with the use and curing of these clays includes NTP findings as well as test information for the potential for phthalates to be released during curing. Read a summary of the assessment.

Crystalline Silica

California's OEHHA proposed an inhalation reference exposure level (iREL) for crystalline silica of 3 micrograms/m3 for a particle distribution with a mass median aerodynamic diameter (MMAD) of 10 microns or less. Particles with a low MMAD (4 microns or less) can readily get deep into the lung where larger particles deposit in the nose. The basis for their proposed iREL are studies where exposures were characterized to respirable crystalline silica particles with a distribution with a MMAD of 4 microns. Most environmental exposures to crystalline silica occur from natural sources where quartz particles predominate in the larger sized dust fractions. Choosing a MMAD of <10 microns for this iREL will increase the apparent crystalline silica exposure levels by as much as an order a magnitude above levels that would reflect exposures within the respirable range on which your iREL is based. This paper gives the basis for using a MMAD of 4 microns or less for California’s crystalline silica iREL.

Soluble Cobalt

ATSDR has proposed a minimum risk level (MRL) for soluble cobalt based upon a therapeutic effect, increases in hemoglobin. This comment recommends that toxicity-related endpoints, cardiomyopathy and thyroid dysfunction, be used to determine the MRL. 

A risk assessment based on this approach has been published in the following paper:

The bioaccessibility (solubility) of cobalt compounds using various media, including synthetic intestinal juice, is studied in the following paper:

Solvent-Based Markers

Duke toxicologists have completed two studies that examine solvent exposures to users of solvent-based markers.

  • “Solvent Exposure to Graphic Artists” examines xylene exposure from professional use of xylene-based markers by graphic artists. Findings include that the maximum exposure to xylene averaged 0.5 ppm, even when use was for as much as 210 minutes a day or an average of 102 minutes a day.
  • “Solvent Exposure During Use of Solvent-Based Whiteboard Markers” examines solvent exposure from simulated classroom activities involving solvent-based whiteboard markers. Exposures projected to 25 users working simultaneously in a poorly ventilated classroom showed low exposures. 

Asbestiform Fibers in Crayons

Concern has been raised because of the finding of asbestiform fibers that are chemically transitional between asbestos and in talcs used to make crayons. Read more about this issue on the ACMI website or read the CPSC position paper on asbestos fibers in crayons. See also Duke toxicologist Dr. Woodhall Stopford's comments concerning the National Toxicology Program's consideration of listing of talc as a carcinogen.

Acid Yellow 42

ACMI requires chronic health hazard labeling for this dyes that can be metabolized in the gut to benzidine. Acid Yellow 42 is a benzidine-based dye that is sulfonated and has been shown not to be reduced to benzidine.