Traditional Sculpture Hazards
By Michael McCann, Ph.D., C.I.H., and Angela Babin, M.S.
Plaster can be carved, modeled, and casted. Varieties of plaster include: Plaster of Paris, casting plaster, white art plaster, molding plaster, and Hydrocal. These are all varieties of calcined gypsum, composed of calcium sulfate. Plaster is mixed by sifting the powder into water. Sometimes salt, potassium sulfate, or potassium alum is added to speed setting, or borax, diluted acetic acid, or burnt lime is added to retard setting of the plaster. Silica sand, vermiculite, sand, and coarse stone can be added to the plaster for textural effects. Wet or dry plaster is carved and modeled with special plaster carving chisels, knives, rasps, and scrapers and other tools.
1. Plaster dust (calcium sulfate) is slightly irritating to the eyes and respiratory system. In situations where there is heavy inhalation of the dust, more severe respiratory problems can result.
2. Potassium sulfate and potassium alum are slightly toxic
by ingestion; potassium alum is slightly toxic by skin
contact, and can cause mild irritation or allergies in some
4. Concentrated acetic acid is highly corrosive by
ingestion, inhalation, and skin contact.
1. For mixing large amounts of plaster at one time, wear
a NIOSH-approved dust mask. Vacuum or mop up plaster
dust carefully; do not sweep.
Mold releases used with plaster include vaseline, tincture of green soap, auto paste wax-benzine, silicone-grease-benzine, and mineral oil-petroleum jelly. In waste molding, the plaster mold is chipped away.
1. Benzine used with many mold releases is moderately
toxic by skin contact and inhalation, and is highly toxic by
ingestion. It is also flammable.
1. Wear gloves and goggles when pouring benzine. Store
in safety containers and do not use near open flames or
Plaster can be finished in many ways. It can be painted with paint or powdered pigments, or dyes can be added directly to the plaster mix. Patinas are made by sealing the plaster with shellac or acrylic sprays. They can also be made with a 50/50 mixture of water and white glue, with water-based glue mixed with a 50/50 mixture of lacquer and alcohol, or with bronzing liquids.
1. Powdered pigments and dyes are often hazardous by
inhalation or ingestion, and in some cases by skin contact.
See our data sheet "Art Painting and Drawing" and
"Dyeing Safely" for more information on the pigments used
to finish plaster.
1. Wear a NIOSH-approved dust mask when using
powdered pigments or dyes. Brush or dip dyes or paints
rather than spraying.
STONES AND LAPIDARY
Stone carving involves chipping, scraping, fracturing,
flaking, crushing, and pulverizing with a wide variety of
tools. Soft stones can be worked with manual tools
whereas hard stones require crushing and pulverizing with
electric and pneumatic tools. Crushed stone can also be
used in casting procedures.
Soft stones include soapstone (steatite), serpentine,
sandstone, African wonderstone, greenstone, sandstone,
limestone, alabaster, and several others.
Hard stones include granite and marble. Electric tools
include saws, drills, grinders, and sanders, and pneumatic
tools include rotohammers, drills, and other tools powered
by compressed air.
Stone casts can be made using Portland cement, sand,
and crushed stone. Marble dust is often used with this
technique. Cast concrete sculptures can also be made
using sand and Portland cement. The commonest mold is
plaster with stearic acid/benzine as the mold release.
Portland cement contains calcium, aluminum, iron and
magnesium oxides, and about 5% free silica. Some
modern cements have acrylic resins in them to give
stronger bonding. Sometimes, fiberglass is added as a
1. Sandstone, soapstone, and granite are highly toxic by inhalation because they contain large amounts of free silica. Limestone, containing small amounts of free silica, is less hazardous. See Table 1.
2. Serpentine, soapstone, and greenstone may contain asbestos, which can cause asbestosis, lung cancer, mesothelioma, and stomach and intestinal cancers.
3. During chipping and other carving, flying chips and
pieces of rock may cause eye injury. Grinding and
sanding can release small pieces of stone and dust which
are hazardous to the eyes.
5. Power tools create larger amounts of fine dust than hand tools. Pneumatic tools can create large amounts of fine silica dust.
6. Pneumatic and electric tools and compressors can create
a noise hazard. Temporary hearing loss can become
permanent with chronic exposure and noise can also
adversely affect the heart, circulation, blood pressure,
intestines, and balance.
1. Do not use stones which may contain asbestos unless
you are certain that your particular pieces are asbestos
free. New York soapstones may contain asbestos, whereas
Vermont soapstones are usually asbestos free. Alabaster is
8. Pneumatic and electric carving tools should be equipped
with portable exhaust systems.
12. Tie long hair back, and don't wear ties, jewelry, or
loose clothing which can get caught by machinery.
Lapidary involves cutting and carving semiprecious stones
and has similar risks as hard stone carving. Stones carvedinclude garnet, jasper, jade, agate, travertine, opal,
turquoise and many others.
1. See stone hazards above.
2. The dust from quartz gemstones such as agate,
amethyst, onyx, and jasper is highly toxic because they are
made of silica. Other gemstones such as turquoise and
garnet may be contaminated with substantial amounts of
free silica. Opal is made of amorphous silica, which is
slightly toxic by inhalation.
1. See stone precautions above.
Stones can be finished by grinding, sanding, and
polishing, by either hand or with machines. Polishing can
use a variety of materials, depending on the hardness of
the stone being polished. Polishing materials include
carborundum (silicon carbide), corundum (alumina),
diamond dust, pumice, putty powder (tin oxide), rouge
(iron oxide), tripoli (silica), and cerium oxide.
1. Grinding and sanding, especially with machines can
create fine dust from the stone which is being worked.
There are also inhalation hazards from grinding wheel dust
(especially sandstone wheels). Some polishing materials
such as tripoli are highly toxic if inhaled in powder form.
NOT SIGNIFICANT OR SLIGHT HAZARDS,
Modeling materials used in sculpture include traditional
moist clays, non-hardening modeling clays, self-hardening
clays, oven-hardening clays, wax, and papier mache type
products. See our data sheet "Ceramics" for more
information on clay.
Modeling clays of the plasticine type usually contain
China clay in an oil and petrolatum base. Additives are
often present, including dyes, sulfur dioxide, vegetable oils,
aluminum silicate, preservatives, and turpentine. These are
modeled and carved with simple tools.
There are also a variety of polymer clays that are self-hardening, or oven-hardening (e.g. FIMO, Sculpey), which
are not really clays at all. These are often based on
polyvinyl chloride. They are widely used in jewelry and
bead-making, and sometimes are inappropriately used with
1. Some of the additives in plasticine clays such as turpentine and preservatives might cause skin irritation or allergies, and sulfur dioxide might cause some respiratory problems in certain asthmatics. The amounts present are usually small.
2. In the past, many of these materials contained di-(ethylhexyl) phthalate (DEHP), a probable human
carcinogen, as a plasticizer.
1. Use gloves or apply a barrier cream to hands if skin irritation results from using plasticine modeling clays. Wash hands with soap and water after contact.
2. Baking any art material in an oven which is also used
for food carries the risk of contaminating food. Use a
separate oven, that has reliable temperature control and
only bake these products to their particular hardening
4. Do not use hardening modeling clays that have DEHP as a plasticizer. At this time, the longterm hazards of replacement plasticizers have not been adequately researched.
5. Use these products in front of a window exhaust fan.
Many different types of waxes are used for modeling,
carving, and casting. These include beeswax, ceresin,
carnauba, tallow, paraffin, and micro-crystalline wax. In
addition there are the synthetic chlorinated waxes. Solvents
used to dissolve various waxes include alcohol, acetone, benzene, turpentine, ether, and carbon tetrachloride.Waxes are often softened for carving or modeling by
1. Overheating wax can result in the release of flammable wax vapors, as well as in the decomposition of the wax to release acrolein fumes and other decomposition products which are highly irritating by inhalation. Explosions have occurred from heating wax that contained water.
2. Alcohol and acetone are slightly toxic solvents by skin
contact and inhalation; benzene and turpentine are
moderately toxic by skin contact, inhalation, and ingestion.
Carbon tetrachloride is extremely toxic, possibly causing
liver cancer and severe liver damage, even from small
exposures. Exposure to carbon tetrachloride can be fatal
by skin absorption or inhalation.
1. Do not overheat waxes. Use a double boiler and a
temperature-controlled hot plate, or a crock pot. Do not
2. Use the least hazardous solvent to dissolve your wax. Do not use carbon tetrachloride under any circumstances. Store solvents safely, do not smoke or have open flames near solvents. Dispose of solvent-soaked rags in an approved waste disposal container which is emptied daily.
3. Do not use chlorinated synthetic waxes.
FOR FURTHER INFORMATION
Written and telephoned inquiries about hazards in the arts
will be answered by the Art Hazards Information Center ofthe Center for Safety in the Arts. Send a stamped, self-addressed envelope for a list of our many publications.
Permission to reprint this data sheet may be requested in
writing from CSA. Write: Center for Safety in the Arts,
5 Beekman Street, Suite 820, New York, NY 10038.
Telephone (212) 227-6220.
CSA is partially supported with public funds from the
National Endowment for the Arts, the New York State
Council on the Arts, the New York City Department of
Cultural Affairs, and the NYS Department of Labor
Occupational Safety and Health Training and Education
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