Permethrin

I just found on the sawyer website it does not come off clothing in quantity great enough to harm fish. If anyone knows different please let me know.

I think I read that a lot comes off in the first washing, but after that the amount that washes off is significantly less. I considered using it for my caving gear, since access to caves in the Southeast often involves bushwhacking with a lot of ticks, but I decided not to because I was afraid it might be harmful to the delicate aquatic ecosystems in caves. Outside a cave I wouldn't worry about it as much, but if you are going somewhere that's particularly sensitive it would be a good idea to wash the gear once after treatment before use.

That sounds like sound advise thanks Matt

You can send your clothing to Insect Shield to have it treated for ~$10 per item (they offer quantity discounts).

According to the IS research page after 70 washings the treatment remains between 80.8-96.7 effective against mosquitos (depends of species) and 95.8-100% effective against ticks. Obviously this is their marketing, but it is “EPA-registered to last through 70 launderings”. I have IS treated clothing that is 3 years old and still repels flying/crawling insects like when it was new.

My guess is that it doesn’t wash off…not into the laundry water, not into a stream, not onto you in the rain. As always…make up your own mind as to how to treat your clothes.