This page contains a dictionary of potentially harmful metalsmithing substances from an article that was originally published by SNAG as series of research presentations, which was given at a SNAG Conference, during 1977-1980. Aided by a grant from the National Endowment for the Arts, they were published in 1981 as a single volume called, “The Metalsmith Papers“. “Metalsmith Magazine” was being published concurrently.
Antimony; Cadmium; Chromium compounds; Copper compounds; Gold; Lead; Magnesium compounds; Manganese compounds; Mercury; Nickel compounds; Pewter; Platinum; Silver compounds; Stainless Steel; Tellurium; Tin compounds; Titanium; Zinc compounds.
Ammonia; Asbestos; Flourides; Fluxes; Hydrogen Sulfide; Investment; Liver or Sulfur; Mica; Pitch; Solder; Styrofoam; Sulfur Dioxide; Talc; Teflon; Wax.
Abrasives – See individual listings for silicas and dusts.
Acetone – A solvent. Very flammable. Flash point – 4 degrees F. Acute toxic effects: headache, drowsiness, irritation of eyes, nose, threat; vomiting. It is one of the least toxic solvents, is quickly eliminated by the body, and has little residual effect. Because it is highly flammable, it should be used with great care. Acetone will dissolve surgeons rubber gloves.
Acetylene – Fuel. Commonly used in cylinder form. In low concentrations, acetylene is a mild narcotic or intoxicant. In large concentrations, it can cut off oxygen supply. Commercial acetylene is contaminated with Phosphine, Hydrogen Sulfide, Arsine, Carbon Disulfide and Carbon Monoxide – all are extremely toxic. See individual listings for these substances. Acetone is always present in the cylinder – Do Not Lay the Cylinder Down!
Acids – See individual listings. Most acids are caustic and irritating to the skin, mucous membranes of the nose and eyes, and the lungs. Always add acid to water , never the reverse! Heat is usually generated and an explosion could result. When working with acids, one should wear protective clothing, work under an exhaust fume hood and have an eye wash station close by. Respirators for acids are different than respirators for particulates. Acids should be returned to the distributor for proper disposal.
Ammonia – Usually used for cleaning buffing compounds from a piece – It is caustic to the lungs, may lead to pulmonary edema (when lungs fill with fluid), or pneumonia and lung warring. It is an eye irritant both in solution and in gas form (fumes), usually damaging the cornea. Effects of long-term exposure to ammonia in low doses haw not be studied, but this would probably perpetuate chronic bronchitis and emphysema. Ammonia would best be used in extremely diluted solutions of soap and water.
Aqua Regia – This acid, called “royal water”, is very powerful. It will dissolve or etch gold as well as silver. It is made by adding one part nitric acid very slowly to three parts hydrochloric acid. Its bottle should never be tightly stoppered. Its fumes are highly corrosive, and it should be stored and used in an area that is well ventilated.
Arsenic – released in fumes from some enamels when fused. Causes skin cancer, thickening of the keratin, or outer layer, of the skin, and perforation of the nasal SW turn. Causes nerve function disorder. Kilns should be well ventilated.
Asbestos – is mostly harmful in dust form. It is frequently used for its fire resistant properties. It is a carcinogen – its effects take 2030 years to develop in humans. It causes Asbesteosis , a lung scarring and Mesothelioma , cancer of the lining of the chest. Asbestos is the only cause known of these two diseases. It is an insoluble substance, one that will not dissolve in the blood and tends to remain in the lungs for long periods of time; the lungs cannot remove it or destroy it.
“Asbestos is a fibrous material, Like cotton, its fibers can be made into thread and cloth. Unlike cotton, its fibers are as strong as piano strings.” These very strong fibers are very tiny also and can float like water vapor in the air, rarely settling. They are virtually indestructible in the body, and in the environment. Asbestos also has been found to haw the ability, and tendency, to absorb other harmful chemicals onto its surface. It can also cause cancer of the intestinal tract, stomach and rectum. Alternatives that can be substituted for asbestos are: pea pumice, as is found in annealing pans; charcoal blocks; fire bricks; magnesium blocks; Wesgo refractory block; heavy leather gloves and aprons. Also, if a costing crucible is properly prepared by melting borax in it, and students are carefully supervised, asbestos lining of a crucible will not be necessary. Substitutes for asbestos fabrics, like gloves and fireblankets, are KEVLAR and REFRASIL. “It has been found that smokers have 10 times a greater chance of getting lung cancer than non-smokers. Non-smokers who work with asbestos have 10 times the chance of getting lung cancer as people who do not contact asbestos. But people who both smoke and work with asbestos have 100 times the chance of getting lung cancer.”
Benzene – a solvent for plastics. Very flammable. Flash point 12 degrees F . Intoxication, coma, respiratory failure; can be fatal. Causes severe damage to bone marrow leading to fatal anemia or leukemia. Use an alternative, less toxic solvent. DO NOT USE! Solvents, like acids, should be returned to the chemical distributor for proper disposal. Do not pour down plumbing.
Cadmium – is found in silver soldering and silver brazing compounds. Cadmium fumes can occur during caving and welding also. Know if your alloy contains cadmium. Change alloy or provide good ventilation. Cadmium affects the brain, nervous system, lungs, kidneys, bone, prostrate and digestive tract. It can cause acute bronchitis, pneumonia, digestive disorders, dermatitis, allergic hyper sensitization, chronic brain damage, lung damage, prostate cancer and kidney stones. Because of its extreme toxicity, products containing cadmium are required by law to be labeled. Ask your supplier to label solders.
Carbon Monoxide – incomplete combustion when firing kilns, doing welding or copper enamel. Carbon monoxide poisoning affects the blood hemoglobin preventing the transport of oxygen to the heart, brain and lungs. It can be detected in extremely advanced stages bemuse the victim’s face and fingernails turn cherry red. Good ventilation will prevent carbon monoxide poisoning in the average studio. It should be remembered that carbon monoxide is colorless and odorless.
Chlorinated Hydrocarbons – solvent for plastic and waxes; very toxic – Dissolves fatty layer of the skin, causes dermatitis, liver and kidney damage. In general, try to replace chlorinated hydrocarbons with less toxic substances. When this is not possible, use good exhaust ventilation and wear protective gloves. Neoprene rubber is best – do not use butyl rubber or natural rubber.
Chromium Compounds – fumes from chromium compounds are produced in welding. There is a much greater danger from a gas or fume form than from solid form of most toxins. It affects the skin, dermatitis, lungs; inflammation, asthma, and cancer; lining of the nose and nasal system. Use good ventilation.
Copper Compounds – copper has been found to be highly toxic to animals in test situations, but there has been little testing in industrial circumstances involving people. Fumes of copper oxide are poisonous, irritating the lungs and intestines. It causes metal fume fever; recovery is usually complete in 1 or 2 days. Eyes and skin are sensitive to copper. There is no conclusive evidence about long-term exposure. Good ventilation is recommended for processes that involve heat, leading to the formation of Copper oxides. If the metalsmith find some type of dermatitis developing, he/she may want to wear gloves when handling copper-containing alloys.
Cyanides – sodium cyanide, ferrocyanide, cuprous cyanide and free cyanide are all used in electroplating bath formulas. It is known that the mist of cyanides am harmful, and one should use good ventilation and/or the appropriate respirator. It is also suspected that cyanide mists cause harm when absorbed through the skin, so protective clothing is advised.
Epoxy Resins – cause contact dermatitis. It is recommended that gloves be used. During the mixing and curing processes, use good ventilation and avoid inhalation of dusts and fumes, and avoid skin contact with uncured epoxy resin and hardeners.
Ferric Chloride – used as a metal etching acid when a sharper etch is desired than can be achieved with nitric acid. Can irritate the skin and the respiratory tract. Use protective clothing and good ventilation.
Flourides – found frequently in fluxes. They produce hydrogen flouride vapors which dissolve in the lungs where they produce hydroflouric acid and burn the lungs. Have your supplier label flux contents. Use good ventilation. Avoid breathing fumes.
Flux – see Flourides.
Hydrochloric Acid – (hydrogen chloride) used in metal patinas and etching. An irritant to mucous membranes. In mist and gas forms, this acid can damage lungs, cause tooth erosion and damage cartilage in the nose. Use good ventilation and prevent skin contact.
Hydrogen Flouride – (hydroflouric acid) used in enameling to etch glass. Skin contact should be avoided. If it does occur, flush area with water and see a doctor. Fumes affect the lungs, leading to bronchitis, pneumonia, etc. Do not breathe acid mists.
Hydrogen Sulfide – a byproduct of using liver of sulfur in combination with water and heat. It is characterized by an odor like “rotten eggs”. See Liver Of Sulfur. 10ppm (parts per million) is the threshold limit value. It is more toxic than cyanide. In high concentrations it can paralyze the olfactory nerve.
Lead – lead is a cumulative poison. Its compounds and its oxides should be treated carefully. It can be found in some bronze alloys and in some enamels (and we are all exposed to it from automobile exhaust fumes). It is harmful in dusts and in fumes, causing damage to the brain, central nervous system, red blood cells, bone marrow, liver and kidneys. Use protective measures and good ventilation. Lead fumes are very toxic. The body will absorb five times as much lead into the blood via the lungs than from the digestive tract. The body will retain lead for long periods of time, leading to cumulative poisoning; it is stored in the bone marrow.
Ketones – acetone, methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone, ethyl acetate, amyl acetate. Lacquer thinner is a mixture of several of these solvents. Flash points vary from -4 degrees F to +89 degrees F. Ketones are skin, eye and respiratory tract irritants. They cause defatting of the skin and peripheral nerve damage. Use gloves and good ventilation and/or appropriate respirator.
Lacquer Thinner – see Ketones
Liver Of Sulfur – is potassium sulfide and it is used to oxidize metal (gold, silver, copper). When it is heated to decomposition, it will emit highly toxic fumes of oxides of sulfur- These can react with moisture to produce another toxin – hydrogen sulfide, which is caustic to the eyes, the lungs and corrosive to mucous membranes. In high concentrations (around 700ppm) it can cause suffocation and brain damage. Wear a respirator and work in a well ventilated area. (see Hydrogen Sulfide) .
Magnesium Compounds – in the forms of m. silicate, m. chromate, or oxide. Encountered in welding fumes. It is known to affect the lungs, cause digestive disorders, metal fume fever, and is believed to affect the central nervous system. Use good ventilation when welding.
Manganese Compounds -m. carbonate, m. dioxide-black, m. dioxide-green, m. sulfates. Manganese is encountered in fumes from welding (it is frequently used to coat welding rods) and enameling. It affects the liver, lungs and central nervous system. Symptoms are headache and weight loss. Diseases that can result are pneumonia and manganism which is a permanently crippling disease of the central nervous system similar to Parkinson’s Disease. Provide good ventilation in welding areas.
Mercury – mercury is a cumulative poison. It may be encountered in gold and silver refining, and in welding, It affects the brain, kidneys and nervous system. Mercury can be used to gild silver; however, electroplating is more commonly used.
Methanol – (methyl alcohol) is often found in a small percent in denatured alcohol which is frequently used as a solvent for pitch, and a fuel for alcohol lamps that may be used when working up wax models for castings. In high concentrations, it attacks the respiratory system, gastro-intestinal system, central nervous system, the liver and the optic nerve. Use proper ventilation.
Nickel Compounds – nickel is found in the alloy called German Silver. n-oxide-green, n. oxideblack, n. carbonyl – are byproducts of welding nickel alloys, like stainless steel. Nickel carbonyl is the most toxic of the nickel compounds. Its gas can be absorbed by inhalation and through the skin. Body systems affected are the lungs (asthma and cancer) and the central nervous system. Skin contact with nickel salts may cause nickel itch, an allergic dermatitis. Once this sensitivity develops, the person will react to even extremely small amounts of nickel. Wear protective clothing and work in a well ventilated area.
Nitric Acid – usually used for etching metal. Very irritating to lungs. Symptoms of overexposure are chills, fever, and chronic cough. When etching copper, nitrogen oxide fumes are produced; these dissolve in the lungs and can cause pulmonary edema and chemical pneumonia. Also, very irritating to the eyes. Exposure to low concentrations over extended periods of time are cumulative in terms of burning and scarring of the lungs. Wear Protective clothing and work in a ventilated area or mar a respirator designed to cope with acid mists. Return all acids to the chemical distributor for proper disposal. Do not pour down plumbing or dump outside.
Oxy-Acetylene – (see Acetylene) Use eye protection with tinted glass that is impact and heat resistant and will prevent penetration of radiation.
Ozone – occurs during welding. It destroys enzymes in body tissues. It has a distinctive odor (you can smell it during a lightning/thunder storm). Prolongs inhalation above 0.05ppm can cause burning of the cells in a manner similar to X-rays- It can be detected by continuous monitoring devices.
Pewter -pewter used to be made from tin and lead. Modern pewter is an alloy of tin and antimony and copper. Extreme care must be used if one is working with the older alloy because of its lead content.
Pitch – when pitch is made from a coal tar derivative like asphalt, it can be a skin irritant and photo sensitizer, leading to skin cancer after repeated, intermittent exposure over many years. When using pitch for chasing, repoussé and engraving, it is advised that gloves be worn when handling the pitch itself. Once the work is secured in the pitch, the gloves can be removed to use your chasing, repoussé, and engraving tools efficiently. If the fingers need to be braced on an area that is exposed to pitch, the pitch can be covered with Saran wrap with a very thin coating of petroleum jelly, if desired, as a separating agent between the Saran wrap and pitch.
True “Brown Swedish Pitch” is a pure vegetable pitch and can be differentiated from pitch adulterated with rosin and bitumin (coal tar products) by color; it is brown and has an agreeable odor. Pitch that is not the pure vegetable type is black and gives off offensive vapors. To test for color, Swedish pitch, when melted and pulled out very thin, shows clear translucent brown when held to a light. Precautions should be used when working with either type of pitch but the Brown Swedish Pitch is far less hazardous.
Care should be taken not to overheat pitch. Boiling destroys the tenacity and it becomes a fire hazard. Pitch, when heated, tends to form a skin on its top surface and to trap explosive gases underneath. To avoid this, heat the pitch slowly and evenly, occasionally stirring to break the skin and release these gases. It is wise to use good ventilation when melting either type of pitch.
Extra care is needed when a large bodied vessel with a narrow opening has to have pitch removed from it. Pitch expands with great force when heated. If the mouth of the vessel becomes clogged with hard pitch, while the pitch behind it approaches the melting point, an explosion can result. This problem can be solved by laying the vessel so the opening is a little lower than the body and warming the opening first. When the opening has been cleared of pitch, direct the soft flame to the “top” of the vessel.
Platinum – metallic platinum is nontoxic, but some platinum compounds can cause contact dermatitis and respiratory allergic reactions which have been known to lead to asthma and emphysema. Fumes from platinum that are encountered in soldering, casting, or refinishing, should be avoided. They are lung and skin irritants.
Polyester Resins – one of the many plastics that metalsmiths use. They are skin irritants, and protective clothing should be worn. When casting these substances, harmful vapors are given off from catalysts, thickeners, binders and other additives. They should be used with good exhaust ventilation or respirators. Read the labels regarding proper storage. Some organic catalysts are heat sensitive and explosive.
Silica – encountered as abrasive dusts, in metal finishing procedures, sand blasting, buffing, sanding, etc., and in lapidary work. Silicosis, a lung scarring disease, results. Wear a mask for particulates, Some substitutes are silicon carbide, steel shot or glass beads.
Silver Compounds – s. chloride and s. nitrate. Absorption of silver into the tissues is called argyria. This is indicated by a blue black discoloration in the skin and eyes. (This is not the same as when your skin will turn gray from silver jewelry – this is a coloration IN the skin that cannot be washed off.) These silver compounds harm the body when they are in vapor or dust form. When using mechanical devices for abrasion (sanding, buffing, etc.) of silver, wear eye protection because silver deposits in the eyes will cause night blindness. Other body parts affected are the lungs and kidneys.
Solvents – used for machinery clean-up and maintenance, dissolving plastics, and removing pitch. Solvents can enter the body by inhalation, skin absorption or ingestion. Ingestion is rare. Wash hands before going to eat. Wear gloves when working with solvents; do not smoke when using solvents (this also presents a fire hazard). Swallowing solvents is usually fatal and will cause blindness. All solvents should be used with good exhaust ventilation. The ventilation should be at the same level as the work rather than above the work. Gloves should be worn to prevent skin contact; solvents can dissolve the fatty layers of the skin and can cause systematic poisoning. See Acetone, Ammonia, Benzene, Ketones, Methanol, Tolune, Turpentine, Xylene. Please note that this is a very broad definition for solvents. It would be wise to investigate more thoroughly the specific products in use in your own studio. When in doubt return solvents to a local distributor. If your supplier can’t tell you who the distributor is, check with local machine shops, the national manufacturer or your state board of NIOSH. (National Institute of Occupational Safety and Health)
Stainless Steel – when welding stainless steel, harmful nickel compound fumes are produced. See section on Nickel Compounds. Do all welding in a well ventilated area.
Styrofoam – occasionally used for models for casting. Heating styrofoam for forming and for burnout releases toxic gases and requires efficient exhaust ventilation. All styrofoams are different. Contact your supplier for a Safety Data Sheet.
Sulphuric Acid – used for cleaning metals. Very irritating to the respiratory tract, skin and clothes. Sparex is a product used as a substitute for sulphuric acid. Both substances can be neutralized with bicarbonate of soda and water or soapy water. Many metalsmiths make the mistake of thinking that SPAREX is harmless. This is not true! Sparex is sodium bisulfate in granular form. This makes for safer, convenient storage than is possible with pure sulphuric acid. However, once Sparex is mixed with water, it is as comparatively dangerous as sulphuric acid, especially when it becomes concentrated due to water evaporation. When Sparex solution is heated, the fumes given off are equal to sulfuric acid fumes. Use ventilation.
Sulfur Dioxide – is found in fumes from tin compounds when they are melted. It is also a breakdown product of liver of sulfur. It is harmful to breathe sulfur dioxide gas. It is a highly soluble gas and dissolves in the watery passages of the breathing tubes. It does most of its damage in the upper respiratory tract which will then go into spasms and prevent the gas from getting further into the lungs. This gas is also encountered in environmental smog and is considered to be a major eye irritant. Use ventilation and/or appropriate respirator.
Talc – occasionally used as a separating agent with rubber molds and frequently used in plasters. Talc is mined from mineral deposits that frequently contain asbestos. So far, it has not been determined if the health problems caused by tale are from the talc, or the asbestos, or both – American talc tends to have less asbestos content than French. Like with asbestos, the lungs cannot remove talc. Most diseases related to talc take 20 to 30 years to show up. It is advised that a dust preventative respirator be worn because most damage caused by tale is to the respiratory tract.
Tellurium – fumes generated in copper, silver and gold refining and alloy making; also in welding. Extremely poisonous. Attacks the skin and the gastro-intestinal system. Early symptoms am “garlic” breath and a metallic flavor in the mouth. Use good exhaust ventilation.
Tin Compounds – are harmful in dust form and in fumes. Tin is found in bronze alloys, pewter and solders. Organic tin compounds are skin-irritants. Stanosis is a “disease” caused by dusts of tin oxide that are in the lungs- These dusts are insoluble in lung tissue but are not irritating, do not cause symptoms and do not appear to cause disability. They will appear in X-rays of the lungs. However, if inorganic tin compounds are eaten, they can be fatal. Avoid breathing fumes and dust.
Toluene / Toluol -is an alternative solvent for Benzene. Its flash point is 40 degrees F. It can produce intoxication, hallucinations, lung and brain damage and fatal cardiac arrythmyias. Toluol can damage the red blood cells. It should be used with the appropriate ventilation.
Wax – many of the waxes that are used for models for casting contain plastics to give them desirable working characteristics. When these waxes are melted for modeling or burnout, the plastics can give off harmful vapors which should be avoided.
Xylene – alternative solvent for Benzene. It is a skin irritant; dissolves the fatty tissues; can cause a decrease in the number of red and white blood cells. It is an eye and upper respiratory irritant. Wear gloves and use good ventilation.
Zinc Compounds – are found in solders and alloys of brass, bronze, German silver and gilding metals. Zinc acetates and zinc oxide are harmful in dons and fumes. All soldering and welding should be well ventilated. The pans of the body affected are the central nervous system, lungs and skin (dermatitis) ­ Symptoms of zinc oxide fume poisoning are nervousness and depression and metal fume fever. Metal fume fever indications are: flu symptoms, muscular aches and pains, chills, fever, nausea, burning throat. dry cough. This illness is usually very brief with complete recovery in 12 to 24 hours.