You see this one yet? A byproduct of chlorinated water. This is what is going to happen eventually with plastic recycling. Experts are warning we shouldn't be recycling plastics because not all recyclers follow the rules and mix different types of plastics together and it ends up making a new chemical compound.
Mysterious chemical in tap water identified after nearly 40 years: Is it toxic?
https://www.woodtv.com/news/nexstar-media-wire/mysterious-chemical-in-tap-water-identified-after-nearly-40-years-is-it-toxic/