Department of the Environment and Heritage
Lead used in ceramic glazes can be a health hazard for potters, and for people using their products. A special concern is the intellectual development of young children.
The dangers of lead in pottery
Handling glazes containing lead, even occasionally, can be harmful to human health if dust or fumes containing lead are swallowed or breathed in. When lead glazes are used, strict precautions are advised when mixing, applying or firing them. Where possible, it is better to avoid using glazes that contain lead.
Glazes containing lead
Lead is found in pottery glazes as lead bisilicate in frits. These glazes are mainly used on earthen and raku ware. If they are not properly formulated, applied and fired it is possible that they could leach into food or drink.
Leadless glazes and low-solubility, lead-bisilicate glazes made with frits give lead-release figures well within international standards and they are readily available from most major suppliers. Lead borosilicate frits give a higher lead-release figure and so should be avoided.
Keep yourself and your family safe
It is important to avoid exposure to lead dust and fumes. You should:
- keep young children and pregnant women out of the work area and away from work clothes, supplies, equipment, tools or containers
- refrain from eating or smoking in the work area
- store supplies that contain lead safely and mark the labels with safety information
In your work area
As a potter you should minimise your exposure to lead dust in the studio. Where possible, do as much of the glazing and firing process as possible at properly equipped institutions where the specialised equipment you need (e.g. kilns and casting moulds) is properly vented.
If you decide to work at home, make sure that your studio is adequately contained to prevent lead dust spreading and that it can be easily cleaned. This means working on carpets is not recommended; plastic sheeting is preferable.
Clean all surfaces in the work area, tools and equipment regularly by wet dusting, not dry brushing or sweeping. Clean walls and windows at least monthly with sugar soap that can be obtained from a hardware store or tri-sodium phosphate (TSP) bought from an industrial cleaner stockist. TSP should be mixed at the ratio of at least 25g of 5% TSP to each five litres of hot water.
Vacuum only with vacuum cleaners equipped with HEPA (High Efficiency Particulate Air) filters, which will remove fine lead dust from the workroom. Wet mopping is the next best alternative if a vacuum cleaner fitted with a HEPA filter is unavailable.
Dispose of waste properly
Dispose of waste materials containing lead, including water contaminated by wet mopping, according to State/Territory or local government regulations. The water should be placed in a strong, securely sealed container. Do not pour water down drains or on to the garden.
Products using lead glazes
Lead-fluxed glazes and colours can be acid-resistant providing that they are properly formulated, applied and fired. The main risk to your health occurs when unknown or incorrectly formulated products are used.
When mixing glazes, use a half-face particulate or air-purifying respirator that meets Australian Standard 1716. It should be fitted with a P1 (dust) or P2 (dust and fumes) filter, both of which capture small particles of lead. The respirator can be bought from major hardware stores. Replace the filter regularly.
Wear protective clothing and eye protection at all times. Wash clothes separately from the family wash and shower and wash your hair as soon as possible after your work even though they are not resistant to food acids.
Clear glazes that are commercially available are safe when used according to the manufacturer’s instructions.
When colouring oxides are added to glazes to create an effect, the fired product is less likely to be acid resistant. Indiscriminate mixing of glazes or glaze components should be avoided.
Follow these precautions
- Use only ready-made glazes and decorative colours from a reputable source and read their metal release characteristics.
- Additions to products are not recommended because they could alter the formulation and introduce unknown durability factors.
- Fire the glazes to the recommended temperature. Under-firing to produce special effects could lead to poor durability.
- Do not blister lead glazes on functional ware.
- Remember the use of lead frits in glazes fired above 1170°C is hazardous because it forms lead fumes.
- Make sure your kiln is safe. It should be designed, sited and operated according to statutory regulations and the recommendations of the manufacturers. Remember lead fumes are toxic.
- Keep young children, pregnant women and women of childbearing age well away.
- Avoid using raku-fired pottery for food or drink containers. The low-firing temperature reduces durability, particularly under acid conditions.
For more information
Phone the Department of the Environment and Heritage's Community Information Unit on 1800 803 772.
You can ask for fact sheets about lead lighting, lead in ceramics, and house, automobile and marine paints, as well as lead and your health.
The fact sheet on lead in ceramics has more information on the risks of using lead-glazed products for food consumption.
See also our website at http://www.environment.gov.au/settlements/chemicals/index.html.