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Alumina Toxicology | Ammonia and Latex Toxicity | Antimony Oxide | Are colored porcelains hazardous? | Arsenic Oxide | Asbestos: A Difficult-to-Repace Material | Ball Clay | BARIUM and COMPOUNDS / Toxicology | Barium Carbonate | Bentonite Toxicity | Beryllium Monoxide Toxicology | Bismuth Trioxide Toxicology | Boron Compounds and Their Toxicity | Brown Stain | Cadmium Toxicity | Calcium Carbonate Toxicology | Carbon Monoxide Toxicity | Cesium Toxicology | Chromium Compounds Toxicology | Clay Toxicity | Cobalt Oxide and Carbonate | Cobalt Toxicology | Copper Compounds Toxicology | Copper Oxide and Carbonate | Cristobalite Toxicity | Cryolite and Ceramics | Dealing With Dust in Ceramics | Diatomaceous Earth Toxicology | Dioxins in Clays | Epsom Salts | Eye Injuries Due to Radiation | Feldspar | Fighting Micro-Organisms in Ceramics | Fluorine Gas | Fumes from gas kilns | Gallium Oxide Toxicology | Hafnium Oxide Toxicty | Hydrofluoric Acid Toxicity | Iron oxide and Hematite | Lead Chromate | Lead in Ceramic Glazes | Lead Toxicology | Lithium Carbonate Toxicity | Lithium Toxicology | Man-Made Vitreous Fibers (MMVF) Toxicology | Man-Made Vitreous Fibers Safety Update | Manganese and Parkinsons by Jane Watkins | Manganese in Clay Bodies | Manganese Inorganic Compounds Toxicology | Manganese Toxicity by Elke Blodgett | Manganese: Creativity and Illness by Dierdre O'Reilly | Molybdenum Compounds Toxicology | Nickel Compounds Toxicity | Niobium Oxide Toxicity | Occupational Dermatoses | Overview of Material Safety by Gavin Stairs | Paraffin Toxicology | Perlite Toxicity | Plant Ash Toxicity | Potassium Carbonate Toxicity | Pregnancy and Ceramics | Propane Toxicology | Quartz Toxicity | Quartz Toxicity on Clayart | Rare Earth Compounds Toxicity | Rubidium and Cesium Toxicology | Rutile Toxicology | Silicosis and Screening | Silver Compounds Toxicology | Sodium Azide Toxicology | Sodium Carbonate Toxicology | Sodium Silicate Powder Toxicology | Stannous Chloride Toxicity | Strontium Carbonate Toxicity Note | Sulfur Dioxide Toxicity | Talc Hazards Overview | Talc Toxicology | Thallium Oxide Toxicology | The Use of Barium in Clay Bodies | Thorium Dioxide Toxicity | Tin Inorganic Compounds | Titanium Dioxide Toxicology | Toxicological Assessment of Zeolites | Tungsten Compounds Toxicology | Understanding Acronyms on MSDS's | Uranium and Ceramics | Vanadium and Compounds Toxicology | Vermiculite | Zinc Compounds Toxicology | Zirconium Compounds Toxicity | Zirconium Encapsulated Stains Toxicity

Fumes from gas kilns

Carbon monoxide (CO) is the principle hazard of firing a gas kiln - the same as a gas kitchen stove, water heater or house furnace. A gas kiln, by the necessity of achieving combustion and an even atmosphere and heat distribution, must rely on the chimney to draw air in through the burner ports and pull it through the ware. It is a negative pressure machine, rather like a dust hood. As a result, it is effectively acting as a fume hood. The degree to which it is functioning properly is all about damper adjustment, chimney function, and gas-to-air ratio (gas furnaces take advantage of this phenomenon). Fumes from materials containing heavy metals are generated in the latter stages of firing where it is most important that the kiln be functioning properly or temperature will not be reached (thus fumes are drawn up the chimney). However when back pressure is sufficient, products of gas combustion can be drawn into the room. Cobalt metal fumes at the least of your worries when this happens! Electric kilns are more concerning because the fumes they generate are exclusively a product of the decomposition of materials in the bodies and glazes.

CO poisoning is a genuine hazard. Follow the instructions of the kiln manufacturer carefully. Having a carbon monoxide detector installed in the kiln room is obviously as good idea. If your kiln is fitted with a sensor that measures the degree of reduction that is an extra level of protection.

Fumes can be generated from metal oxides and carbonates of lead, manganese, cobalt, copper, chrome, iron, silver, vanadium. Likely you are not even using most of these. However, keep in mind that car exhaust contains most of these and more.


By Tony Hansen
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Related Information

Do gas kilns produce silica dust?


Are neighbours paranoid about your kiln filling the air with silica dust? Silica is not volatile and does not produce fumes from a kiln. The silica is reactive during firing, busy forming silicates in the glaze and clay body. Silica and silicates make up more than 60% on the earths crust. Your neighbour is exposed to more silica dust when taking a walk, sweeping a floor or gardening than from the stack of your kiln. Gas kilns put out carbon and sulfur compounds, like a car, when fired. These come from the fuel, but also from carbon and sulfates in the clays and glaze materials, as these decompose during firing. Potters make rocks. Rocks are stable, they endure millions of years. If your neighbours want totally clean air they need to move to a place where there are no cars.

Links

Hazards Carbon Monoxide Toxicity
Although not a material used in ceramics and pottery, every technician and potter firing fuel kilns needs to know about the hazards are this.
URLs https://www.amazon.ca/s?k=co+sensor
Carbon monoxide sensors at Amazon
Glossary Reduction Firing
A method of firing stoneware where the kiln air intakes and burners are set to restrict or eliminate oxygen in the kiln such that metallic oxides convert to their reduced metallic state.

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