OK ... Looked it up as a refresher because I need to treat my work clothes for the season.
The concentration you want is .5% to soak your clothing. You can do this with concentrates that range from 10% up to at least 38%. This is FAR less expensive than buying the expensive stuff in some big chain store. Just go to you local coop.
Having wrestled with Ehrlichia myself - similar to Lyme disease - believe me, I take this seriously. Soak your shirt, pants, socks and hat. Any ticks that get on your clothing will die very quickly. This also helps with flies and mosquitoes.
Yes, it is safe. The US military has been using permethrin for over 20 years. It is a natural substance and absorption though the skin from your clothing is extremely minimal if at all.
Permethrin is toxic to fish. Also, in liquid form it will kill your cat. Once it dries on your clothing, it is harmless to kitty.
Using 10% permethrin concentrate
1 gallon of water + 6.75 oz 10% permethrin = 124.75 oz of .5% concentration
Thoroughly soak your clothing and hang to air dry.
Ready to wear.
Wash by hand or on gentle cycle to preserve longevity.
Should last a minimum of 6 washings - perhaps up to 12.