Earlier quoted context omitted.
No they're not. It's an epoxy resin, not plastic. It's BPA.
So, a plastic then? Edit after light scolding by commenter below: BPA is a form of plastic, both in the pedantic sense (it's formed ... plastically... into its product shape) but more importantly in the colloquial sense, "synthetic, plasticky material" and in this general thread "synthetic material with harmful effects on health, probably through hormonal disruption". So, yes, BPA is a resin, it's also a plastic, and…
[0] Bisphenol A (BPA) is a chemical produced in large quantities for use primarily in the production of polycarbonate plastics.
Guess it is. Why is it a problem?
[1] Researchers have found that BPA exposure is linked to a number of health issues, partly because BPA mimics the structure and function of the hormone estrogen
Not to be wagging the finger, but instead of a snarky remark (ending in a question mark, so the reader can't conclude anything from it) a little Googling and posting a correction with the reasoning would be better.
[0] https://www.niehs.nih.gov/health/topics/agents/sya-bpa/index...