https://www.cbc.ca/news/science/tea-bags-plastic-study-mcgil...
https://news.ycombinator.com/item?id=21070351
From that thread:
> Some of these fancy bags (e.g. from tea pigs) are made from polylactic acid. This is derived from corn starch and used in temporary medical implants (it degrades to lactic acid) so hopefully it's safe.