Synergist - May 2012

Organic pigments and dyes. Roughly 2,000 organic pigments and dyes are commercially available, and any may be used in art materials and/or craft textile dyes. Most are nanoparticle-sized, and only a relative handful of them have been studied for chronic toxicity. Many should be assumed to be carcinogens based on their structure. Some artists derive their dyes and pigments from natural sources. The toxicity of a colorant is related to its structure, not its origins. Many toxic and cancer-causing colorants are natural in origin.

Exposure to pigments and dyes. Industrial hygienists must learn how artists work to determine when exposure to pigments is significant. For example, significant exposure can occur during drawing with dusty chalk-like pastels, when sanding, burning or heating dry paint or when spraying paints and dyes. Exposure to ceramic glaze chemicals during use is almost inevitable because the glazes dry to a powder when applied and dust usually is found throughout the glazing area. Glass pigment exposure occurs when pieces are ground and shaped by grinding dry (creating a dust) or wet (creating an airborne mist). Both glass and ceramic glaze metals can become airborne as an invisible fume when heated, and without proper ventilation, the metal fumes settle on surfaces in the area.

Solvents and exposure. Exposure to solvents by inhalation is unavoidable during use since they evaporate into the air. Some also absorb through the skin. Hundreds of solvents are used as diluents, carriers, degreasers and cleaners. The most common types are petroleum distillates, ketones, aromatic hydrocarbons, alcohols, amines and

glycol ethers. Some exotic solvents are used such as turpentine, pine oil and citrus oil. It is important to note that natural solvents are often more toxic than synthetic ones. They are also sensitizers.

Oils and waxes. Many art processes
employ oils and waxes, such as
in oil-based paints, wax resists in
ceramics and batik textile dyeing,
encaustic painting and lost-wax
casting. These oils and waxes release
toxic substances when heated or
burned, including aldehydes such as
acrolein, formaldehyde and a host of
toxic hydrocarbons.

Plastic resins. Common two-compo-nent plastic products used primarily in sculpture or crafts include polyester resins, which contain styrene and are cured with organic peroxides; acrylates; epoxy resins often cured with complex amines and diluted with diglycidyl ethers; and two-component urethane products cured with diisocyanates. These monomers, curing agents and diluents are often highly toxic. Sensitization reactions like allergic dermatitis and asthma are associated with amine curing agents and isocyanates.

Preformed plastic sheets and foam are also used and then machined and hot-wire cut into shapes. Burning plastics release hundreds of chemicals including the monomers and additives such as phthalates and chlorinated and brominated fire retardants. The popular vinyl polymer hand-molded clays used to make jewelry and small objects contain 3 to 25 percent free phthalates. Users are exposed to phthalates by skin contact during forming and by inhalation when (as the product literature directs) the clays are heated in kitchen ovens, releasing phthalates into the air.

Metals. Common metal products used include lead solders for crafts and stained glass, cadmium-fluxed silver and gold solders, nickel/silver casting alloys, beryllium/copper alloys still found in some sculpture and jewelry alloys, and a host of complex alloys used in bronze, brass, white metals and more. Artists machining or welding junk metals may inadvertently be exposed to toxic alloys and solders never intended for art or craft processes.

Minerals. Ceramics, stone and lapidary carving and glasswork involve exposure to minerals. Silica is present in most minerals and clays. Asbestos can contaminate an industrial talc still used in ceramics, some other steatites and soapstones used in sculpture, and certain semiprecious stones such as nephrite, a form of jade. Lead is a common contaminant in sculpture stones such as dolomite. Uranium and other radioactive metals are present in some granites. Industrial hygienists must know the source of each mineral since their composition varies significantly from quarry to quarry.

Photochemicals. Black-and-white photography is still done in many art schools. It involves the use of developers such as hydroquinone, acetic acid to stop the reaction, and chemical washes to clean and harden the print. Most of the liquid chemical baths also contain sulfite preservatives. Air quality tests should monitor sulfur dioxide from the preservatives, acetic acid and formaldehyde from some hardeners. Some types of photo resists and film cleaners also contain solvents.