Probably never. I think it's been at least a decade since the fear over them became mainstream. Yeah, it's possible these things can take time to show up but considering the scale of their presence and how long we have been using them, we would have at least seen some definite relationship between them and some serious health concern. Look at the article itself, the health impact is conveniently buried in the last section, and it just repeats over and over how they can found everywhere in the body but nothing on what can possible happen.

So much of the scare revolves around the same framing, "microplastic" have been found in breast milk/blood whatever, but never seen one mentioning what it can possibly cause. Is it too hard to fathom that the answer is "nothing"?