I poo poo’d my wife on her concern that my mug made in class by my niece has unsafe, lead glaze. I figured the issue was settled long ago and glazes wouldn’t have lead, especially in a class setting where food containers are made regularly. Now, I’m not so sure. I know there are tests, but don’t know so much about them. If I told you it is a darkish forest green with brownish speckles, would that be enough to know it is safe or not?
Its not an exotic color, and isn’t radioactive. But I can see how an art instructor wouldn’t necessarily check to make sure a glaze is food safe.
Can I have confidence that my mug is safe? other than having to test it?
I think it is unlikely that glazes being used by children would contain lead. Most of the lead warnings I have seen for pottery concern items made in foreign countries. Could you contact the place where your niece made the mug?
Do you still have access to the same type of glaze that was used? I’m sure it’d state on the package pretty explicitly if it did contain lead, and was not safe for foodstuffs.
::edit::
I was going to say something similar to SCL, as I also assumed the OP was from 'Murica.
The glaze is likely lead free. What would concern me more is whether the glaze was completely intact. There is almost assuredly lead in the clay itself. I work for the FDA and we do toxic element analysis on ceramic ware. The unsafe items we get are almost always ones with cracked glazes which allows the leachate to come in contact with the actual clay.
We don’t anayze homemade items (technically, they are outside our jurisdiction) so all the unsafe products we’ve analyzed are commercially available. Even items labeled “lead free”, we were able to leach lead from. Presumably, the label refers to the glaze, but if the glaze isn’t intact, then it really doesn’t matter if it was lead free.
Glazes sold in the US are labeled as to whether there’s lead content, and you certainly can still buy lead-containing glazes. When I worked as a pottery assistant in a camp, less than ten years ago, we had lead-containing glazes (it was very hard to find a non-lead-based red, for example), but wouldn’t let the kids put them on food-contacting surfaces. Any responsible program for children will either not use lead glazes (the camp where I work has since phased them out, more because they were sick of having to explain over and over why the kid couldn’t glaze their bowl red than anything else) or will strictly control on what surfaces they can use them, like we did.
While some colors are more likely to have lead in them than others, I couldn’t say from a description whether one does or not. I’d have to see the label on the bottle.
There’s plenty of poisonous glazes in every single pottery supply store.
You are supposed to be aware, but it’s not easy, as many potters are way to casual about it.
So, there are warning signs in every schoolroom that has glazes, if they follow the rules.
And still people bring things in.
I never trust hand made pots for food, nor for “decorative” things like fancy display plates that some relative might decide to put food into without checking.
The tests are cheap, and available at most art supply shops and most pharmacies.
When I test, I find enough lead and other heavy metals to scare me.
My pottery studio has no lead based glazes; they got rid of them many years ago. There are some heavy metals used along the way, or so I’ve been told. I’ve never heard about lead leaching from the clay bodies. I’ll ask about that if I stop by tonight
The folks at the studio said there’s no appreciable lead in any of the normal clay bodies. I’m not sure how cracked glaze would allow any lead to reach the person using the piece when there’s no lead to begin with.
Where is the cite that clay bodies have lead in them? It’s not in any of the ingredients for the ones at my studio, and they’re pretty common clay bodies.