Don’t panic but be aware !!!
Please be aware of this Earthenware Green glaze, fired at 1060 – 1080, usually fired in Stuart Kiln, the small top loader.
The rich dark green colour Is achieved with a mixture of Lead Bi- Silicate (and other materials) plus Copper Oxide. There’s a very small risk of Lead release if acids – Lemon juice / Vinegar – are in contact with the surface .
This is the ONLY glaze that WSP use that there could be an issue with. Copper, which gives Red in the Gas kiln 1260, is absolutely safe at these high temperatures. All the potentially dangerous materials are locked in by the high firing. All the other glazes used at 1060 – 1080 are safe.
Sensible advice would be to use this dark green glaze on the outside of vessels if they’re going to be used for cooking. It’s VERY important if work is being sold that you inform buyers of the risks . If pieces for sale are to be decorative items only there’s no risk.
Please ensure that you provide clear advice to buyers, there could be serious consequences for makers if Health and Safety issues are ignored.