Clay, Glaze and Firing Toxic Materials List

There are three ways ceramic / pottery materials can become a health problem: Ingestion, Inhalation and Absorption through the skin or cuts. Knowing these three pathways, it becomes easier to properly handle ceramic materials and eliminate health risk. Keep food and drink out of the studio, do not hold tools in your mouth, and do not chew on your fingernails in the studio. When material particles are going to be stirred up, use a respirator or dust mask. When working with glaze materials, use latex or rubber gloves. Also wash your hands thoroughly when you are done.

Below is a list of materials and their health risk attributes:

Alumina - Dust is a nuisance to lungs

Asbestos - Causes particularly nasty, incurable fibrosis if inhaled.

Barium Carbonate - is a dangerous form of barium, as it forms a soluble chloride in the stomach and accumulates. It affects muscles, in particular the heart, increasing its excitability, leading to high blood pressure and internal bleeding. Will penetrate the skin. Not recommended for food ware, as it may leach.

Borax - chronic exposure can cause asthma, diarrhea and skin conditions

Cadmium - Used as a pigment in glazes. Can cause respiratory diseases, osteoporosis, cancer and other problems.

Carbon Dioxide - If the oxygen level falls, hearing will decrease, pulse and blood pressure rise.
Carbon dioxide forms during combustion firing processes.

Carbon Monoxide - combines in the body with the hemoglobin in the blood and reduces the availability of oxygen to the body. Symptoms such as headache, dizziness and fatigue appear in healthy people when 10% of their hemoglobin combines with carbon monoxide. Can lead very quickly to drowsiness, then death. Forms during heavy reduction firings.

Chromates and Chromic Acid - may be cancerous. Will also enter the body through the skin.

Cobalt Oxide, Carbonate - can cause liver damage and dermatitis. Will enter the body through the skin.

Copper - salts are irritants to the skin, eyes, and mucous membranes. Inhalation of copper dust and fume results in irritation of the respiratory tract.

Dusts - in all forms in the studio should be avoided. They accumulate over the years and cause emphysema -- not a nice disease to have. Take special care with silica.

Ferrous Sulphite - can be fatal and should be avoided.

Fiber Blanket - especially in the fired state can shed invisible floating fibers that have similar effects to asbestos.

Gases - from salt kilns and reducing kilns, can cause respiration trouble or even acid corrosion of lung tissue.

Gum Arabic - may cause asthma and eye inflammations.

Iron Chromate - may lead to acute pneumonia and cause lung cancer.

Iron Oxide Dust - is poisonous for children and can cause "iron pigmentation" of the lungs, supposedly benign but contentious.

Kaolin - similar to silica.

Lead - is an accumulative poison. It can be stored in the bone structure for years before a fatal dose is accumulated. Beware of raw lead forms, such as white or yellow lead, which are extremely toxic. Use lead frits instead. Do not use for tableware.

Liquid Petroleum Gas - can cause headaches, numbness, chills and vomiting, but is a greater risk as explosive than inhalation.

Magnesium Oxide - is considered noxious, but general rules for dusts still apply.

Manganese - can lead to brain damage and eventually death. Will penetrate skin.

Mica, Muscovite, Vermiculite, Lipidolite - may contain traces of asbestos.

Inhalation of dust - will lead to lung irritation and coughing, possibly cancer, pneumoconiosis, dyspnea.

Nickel Oxide - can cause cancer. Will cause skin irritation ('nickel itch'). Will penetrate skin.

Platinum - may cause asthma.

Potassium Dichromate/ Bichromate - is very poisonous. Can cause kidney failure and is cancerous. Avoid all contact! Not recommended for tableware!

Selenium - affects the liver.

Silica - is ever present in clay materials. Repeated inhalation will cause potentially fatal silicosis, or 'potters' asthma', a form of emphysema. The molecule (especially when fired) has a 'hook' which attaches itself to the lung wall and accumulates and irritates.

Sulpher Dioxide - is a strong lung irritant and can form when firing soluble metal salts.

Talc - similar to silica

Tin Oxide - can result in ' stenosis; supposedly a benign condition.

Titanium Dioxide - causes pulmonary irritation in chronically exposed workers.

Uranium Compounds - cause kidney damage, not to mention the radioactivity.

Vanadium Pentoxide - can cause anemia; it is a respiratory irritant.

Zinc Oxide - primarily a nuisance dust, but exposures to high concentrations can result in respiratory system effects.

Zirconium - contact of the skin with zirconium or zirconium compounds has caused skin granulomas in the form of linear streaks of small papules; also causes pulmonary granulomas after prolonged exposure.

This information is by no means a complete. It is a guide only. It remains the duty of each individual handling these and other substances to insure that the proper safety standards are met, and that he/she is fully informed on the levels of toxicity of the various substances he/she is using. For more information, refer to the relevant literature available on each ingredient

COPYRIGHT Lakeside Pottery LLC ; COPYRIGHT details and linking policy; Protected by Copyscape including reporting to search engines