What do you mean? Dr Tung's is listed under '“Not Our Favorite” Tooth Floss Brands' and considered to contain PFAS (although there appears to be some dispute in the comments).
The actual FA:
https://www.ehn.org/pfas-floss-2658203711.html
And the OP:
https://cen.acs.org/environment/persistent-pollutants/Fast-f...