I learnt about "forever chemicals". A class of manmade chemicals known as PFAS which stands for per- and polyfluoroalkyl substances , they are used widely in our clothing, shoes, and accessories (stuff like rain coats, yoga pants, food packaging and etc).
PFAS are called Forever chemicals because they are nearly indestructible and take thousands of years to break down. PFAS can also resist breakdown in the environment and in our bodies and to add upon this some PFAS, even extremely low levels of exposure can negatively impact our health.
PFAS have been linked to a wide range of health risks in both human and animal studies—including cancer (kidney and testicular , how fearsome), hormone disruption, liver and thyroid problems, interference with vaccine effectiveness, reproductive harm, and abnormal fetal development.
For further info :-
https://en.m.wikipedia.org/wiki/Per-_and_polyfluoroalkyl_substances