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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 | 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

Quartz Toxicity

Quartz, silica, and flint are non-toxic materials having no known adverse health effects from ingestion. However, Respirable Crystalline Silica (RCS) particles sufficiently small to stay air-born long enough to be inhaled and go deep into the lungs where they become lodged. Extended exposures to lower concentrations or less frequent exposures to higher concentrations can cause silicosis. The World Health Organization states that "dust particles are frequently found with dimensions considerably <1 micron and, for these, settling due to gravity is negligible for all practical purposes."

CAS: 14808-60-7 Silica: ACGIH TLV & OSHA PEL: 0.1 mg/cubic meter 8 hr. TWA, Respirable Dust. By comparison iron oxide is considered a safe-to-use material at a TLV of 5.0, kaolin is 2.0, barium carbonate is 0.5, quartz is 0.1-0.05.

Silica is contained in many ceramic minerals (e.g. feldspar), including its pure form of flint. Inhalation over long periods will cause silicosis where fibrosis of the lungs causes shortness of breath and can lead to death in severe cases. Overexposure to silica weakens the body039;s defense mechanisms.

Because of the abundance of silica, potential hazards are widespread. NIOSH in the US has estimated that 3.2 million workers in the USA are exposed to silica dust. Industries affected are quarrying, mining, steel, iron, metal foundries, abrasive blasting, construction, glass and ceramics, paint and pigments, granite and stone industries.

The primary health risk is the inhalation of "respirable" particles smaller than 10 micrometers (about 1/2500th of an inch). Generally, the smaller the particles are, the greater hazard and potential injury to the lungs. Dust particles larger than these are not capable of penetrating the defence mechanisms of the lung. Prolonged exposure may cause delayed chronic lung disease-silicosis. Chronic silicosis may take many years of exposure to develop, but with acute exposure rapid development can occur. In latter stages of silicosis, known as complicated or conglomerate silicosis, lung function may be reduced, resulting in symptoms of shortness of breath.

Quartz rock can be calcined so that it breaks down and grinds much easier. When this is done the material poses a much greater health risk.

The International Agency for Research on Cancer (IARC) has determined from a review of human epidemiology studies that there is limited evidence for the carcinogenicity of crystalline silica.

In the USA, occupational exposure is regulated by OSHA and under the laws of some states. The mining industry is regulated by the Mine Safety and Health Administration (MSHA). In 1992 the permissible exposure limit based on an 8-hour time weighted average concentration of respirable silica is .1 milligrams of quartz per cubic meter of air. OSHA and ASTM agree on this figure.

Studies have been somewhat mixed in results, even where confounding exposures of other carcinogens including radon and tobacco are involved.

Findings on cancer risks associated with silica dust have made it necessary in some states that material safety data sheets reference the findings of IARC.

Silica can be used and handled safely with appropriate work practices and the avoidance of prolonged exposure. Dust concentrations past the limit are invisible to the naked eye, so employers must monitor workers using approved sampling methods.

See Crystalline Silica Q&A from National Industrial Sand Association, 900 Spring Street, Silver Spring, MD 20910. See The American Ceramic Society Bulletin Aug 2000 Page 60 for information on the Crystalline Silica Work Group of ACerS.

By Tony Hansen
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Related Information

N95 Particulate Respirator mask

This designation is an international standard for a general purpose respirator to filter out respirable quartz particles (which cause silicosis). Use one of these when working in a area where ventilation is insufficient to remove all of the dust. Use it also in circumstances where there is temporary generation of large quantities of dust. Do not wear this as a substitute for keeping floors and working areas clean.

Health warning phrases on a bag of ground silica

Why is there a health warning on the top of each box of clay?

Like any dirt, clays contain quartz. Quartz particles, if inhaled in just the right size, can block the tiny air passages in your lungs. Quartz is all around us, it makes up about 12 percent of the land surface and about 20 percent of the Earth's crust. This label is a reminder to reduce dust levels in your studio and working area. You can see specifics about hazards of any of our products by clicking links (on any manfuacturers website) to view the SDS (Safety Data Sheet). It contains references to where you can learn more about working safely.


Materials Silica
Silica, sold as a white powder, is pure quartz mineral. Quartz is pure SiO2 silicon dioxide. It is the most abundant mineral on earth and most used in ceramics.
Materials Crystalline Silica
Hazards Ball Clay
Hazards Quartz Toxicity on Clayart
Quartz is one of the most dangerous materials used in ceramics, yet it is irreplaceable. It is the most abundant mineral on earth, we must learn to use it safely.
Hazards Feldspar
Feldspars are abundant and varied in nature. They contain small amounts of quartz (while nepheline syenite does not).
Hazards Bentonite Toxicity
Crystalline silica in respirable airborne dusts at International Labour Organization
Quartz on WikiPedia
European Industrial Minerals Association safe silica website with information what it is, why it is important and how to work safely with it.
Minerals Quartz
Quartz is the most abundant mineral on earth, it is the main crystalline mineral form of silica (SiO
Glossary GHS Safety Data Sheets
The Globally Harmonized System (GHS) of classifying and labelling chemicals presents material hazard information in a 16-section user-friendly data sheet.

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