In the first year of the study, workers wearing the treated clothing experienced 65 percent fewer tick bites than workers who didnt have treated clothes. This could also be a concern if you hire a pest control service, which may use a pyrethrin/pyrethroid-based insecticide in and around your home. No. It's safe to use on dogs but is extremely poisonous for cats. @sue, none of the reference you added support the answers assertion of danger when dry, in fact some of them imply it is safe when dry and or low doses. Ensure flea treatments are solely designed for cats. Endocrine disruptors mimic or block the activity of your hormones, which can have effects all throughout the body and brain. So please just don't risk it. What effect does permethrin have on cats? It only takes a minute to sign up. For an alternate strategy, I Googled: Does 20 minutes in the dryer kill ticks and found. This suggested to us that wearing [professionally] permethrin-treated clothing even after several launderings still offers some protection from ticks., Still, retreatment of clothing is wise. Permethrin is a pesticide in a class known as pyrethroids, and research suggests that it has some potential health risks. It's the initial application you have to be careful with. None of my vets use Permethrin on any animals, clothes, or garden products.