Permethrin doesn't have many drawbacks that I have ever been able to find. It is an organic substance made of chrysanthemum flowers. (Edit: Oops! It is not organic. It is a chemical derivative of the chrysanthemum. Man-made. I looked it up!) It is safe for pregnant women. I've gotten some of it on my skin by accident and I didn't die. I didn't have any kind of reaction at all. I haven't had it to melt stuff like DEET does but maybe I have just been lucky. Medical grade permethrin is used as an ointment to be used on the skin and hair to kill lice. Sawyers and the stuff you get at Tractor Supply is insecticide grade. Not sure what the difference is? Supposedly it's not good for cats. I don't have cats. Maybe Permethrin is the reason? People do use it in bulk to spray their crops and yards but I've read that it is bad for bees and fish. One drawback is that it doesn't repel bugs. It just plain kills them. You will get mosquito bites with permethrin unless you're lucky enough to have the mosquito to land on your treated clothing and not your bare arm or leg. I still use DEET for mosquitos. In my experience, Permethrin loses it's ability to do it's job on hard surfaces after a couple of days in the sun or after a couple of times being wet. It lasts longer on fabrics and porus material that it can be absorbed into. I believe it is the chemical residue that kills insects. Once the residue is cleaned off, it has to be re-applied. The military impregnates the fabric in it's uniforms with the chemical now during manufacturing. I use it in the camper a few days prior to camping to kill any bugs and spiders that may be hanging around. In the garage, it's great for those little spiders making egg sacks under all your tool boxes, etc. I use it to kill the carpenter bees that bore holes in my deck. Shoot some in the hole...next day there is a dead carpenter bee on the ground. Ta dah! I treat my outdoor clothes every few weeks during the summer. Tent, hammocks, sleeping bags (woobies) and camp chairs get it too. Oh yeah, dog's bed gets it every few weeks as well to keep fleas and ticks at bay. It's a handy product with lots of uses and I believe it to be safe.
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