Monthly Tech-Tip from Tony Hansen SignUp

No tracking! No ads!

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 | | 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 on Clayart

This material was taken from the Clayart discussion group. The name of the author has been lost. If you are the author please contact us so we can credit you.

When Silica (SiO2) combines with other cations to form Silicates, then the SiO2 is no longer "free". Free Silica exists in three forms, amorphous, cryptocrystalline and polymorphic crystalline.

Mining or quarrying of any rock that contains siliceous material may produce hazardous exposures to "free" Silica. Thus, the mining of copper, gold, platinum, tin, uranium or even coal may produce high exposures. Tunneling in rock containing high concentrations of quartz may produce severe exposures. The quarrying of granite, sandstone and slate may produce exposures from the quarry face where modern flame cutters may have increased exposure through all aspects of cutting, dressing, and polishing the quarried stone. Abrasive blasting and other uses such as scouring and polishing where Silica flows may be used may cause rapidly progressive disease. Other significant exposures may occur in glass manufacture, production of pottery, porcelain and lining bricks, boiler scaling, and enamelling.

The production and use of refractory brick containing Silica may pose significant health hazards particularly after they have been exposed to high temperatures as a significant major proportion of the Silica is transformed to cristobalite or tridymite. Bricklayers and others who maintain and dismantle the refractory brick of ovens, furnaces and other similar devices are exposed to a serious silica hazard.

Foundry work is still a major source of "free" Silica exposure. In all stages of the foundry process from core making through "shake-out" to maintenance and repair, "free" Silica exposures occur along with other potentially hazardous exposures to metal fumes, asbestos and toxic gases. As the quartz-containing sand used in the molds is exposed to hot metal, formation of cristobalite may occur. It is not uncommon for such sand to be used on a repeated basis leading to further increases in the concentration of cristobalite.

Silica related diseases

Silicosis in its chronic and accelerated forms varies in its symptoms. It is not uncommon for relatively severe radiological changes to be present. Coughing may develop as the disease advances and in the later stages may be long and stressful. In the early stages of the disease, there is usually very little sputum, but as the disease advances, recurrent bronchial infections occur and sputum becomes common. Dypsnea is perhaps the most significant problem of established Silicosis and this is usually associated with massive changes within the lungs and contraction of lobes. Respiratory failure is the most important consequence of complicated Silicosis. In accelerated Silicosis, the major features of the disease are identical, but changes occur more quickly.

The most important aspect of diagnosis is a history of exposure to "free" Silica. The x-ray changes of silicosis provide in many cases the definitive diagnosis. Classically rounded nodules are the basic elements but in complicated forms, massive densities predominate.

There is no treatment for Silicosis, and previous treatments of miners with inhalation of aluminum dust have not been effective. In fact, aluminum dust itself may be fibrogenic. The only treatment for silicosis is prevention of exposure by reduction of the Silica content of the air.


Silicosis has been known to the general medical and scientific community since the 1930 s. The risk of contracting silicosis in the sandblasting occupations, foundry industry, and masonry trades, (bricklayers, helpers, etc.) has been well documented. In fact, current literature indicates that persons who are exposed to "free" Silica in certain occupational environments are at a greater risk of developing lung cancer.

NIST/ACerS Crystalline Silica Workshop

NIST and The American Ceramic Society held a workshop on Crystalline Silica in Gaithersburg, Maryland, September 2001 to establish the current state of scientific understanding regarding the relationship between surface characteristics, crystal structure and crystal perfection, and other chemical and mineral aspects, and the potential health hazards associated with crystalline silica. The Occupational Safety and Health Administration (OSHA) has created a Special Emphasis Program, which is considering a 50% reduction in the permissible exposure limit (PEL) for crystalline silica.  Such a reduction in the PEL would, at the very least, result in many companies having to invest large sums of money in upgrading their dust collection capabilities, require increased monitoring of air quality within the plants and lead to increased surveillance by OSHA and MSHA. Following are some contact people.
By Tony Hansen
Follow me on

Related Information


Materials Crystalline Silica
Hazards Quartz Toxicity

Got a Question?

Buy me a coffee and we can talk, All Rights Reserved
Privacy Policy