[Infernal]

Many synthetics have a PFOA or PFOS treatment to provide the water resistance, which are pretty terrible chemicals when you end up exposed to them all day on your clothing. They also wear off rapidly with normal use, so previously water-resistant clothing loses that property after a few months to a year depending on how often it is worn and washed.

[LargoLasskhyfv]

From 11 months ago, my take on that:

https://news.ycombinator.com/item?id=27139705

Thinking about it now, I could see how it started on the shoulders, where the straps of my backpack are, and on my back. Basically everywhere where (different) backpack(s) and straps thereof applied load, pressure, friction.