Where is that material?
> However, at temperatures above 500°F (260°C), Teflon coatings on nonstick cookware start to break down, releasing toxic chemicals into the air. [...] Polymer fume fever consists of temporary, flu-like symptoms such as chills, fever, headache, and body aches. The onset occurs after 4–10 hours of exposure, and the condition usually resolves within 12–48 hours.
[1] https://www.healthline.com/nutrition/nonstick-cookware-safet...
What evidence do you have for this claim?
Many ovens have their top temp at 550F. And when the broiler is on, it can go well above that (although in a smaller more focused area).
I would prefer to study and perfect our manufacturing and use of Teflon if there is no alternative to it that is much safer.
And to answer your question, ceramics sometimes have heavy metals to get bright colors (cadmium mostly). Make sure to buy from a reputable manufacturer.