Oh boy...I heard other things...
Over the years, I've heard all kinds of rumors about various cookware.
At the risk of inadvertantly misleading someone (because I am NO expert, by any stretch of the imagination!) I'll say what I can remember.
Please feel free to correct me if you believe differently.
...Coated pots and pans tend to give off microscopic fibers, until they eventually peel
...To make glass heat-proof, they must add enough lead to the glass mixture
...Glazes on some ceramics may be toxic, so look for well-known brand names, or ceramics sold in reputable stores
...Some clays are toxic, so, again, look for well-known brand names, or clay dishes sold in reputable stores (I think I would trust a 'clay baker' from a reputable store...assuming that it was made from non-toxic clay.)
...I believe enamelled pots to be the 'safest', as long as they have no chipped spots that touch the food. Yes, they must be handled carefully, and, yes, they likely can't take high heats, but I like them for certain herbal teas, etc. Clean them immediately to avoid stains, to some extent.
Oprah once showed a simple test for dishes, to see if the glazes used were toxic (contained lead?). Does anyone remember the solution used for this test?
fledgling