Let me throw another factor into the mix. A good friend of mine almost died in a fire, hunting muskox several years ago but he was wearing 100% wool unionsuit, he said the day before he had on synthetic's (polyprop) his hunting partner was wearing Polyprop's and did die. He told me if it hadn't been for the wool garments he knows he wouldn't have lived to tell about it. For that reason if I'm hunting and will be around a camp stove or camp fire, I will wear nothing but wool. Bob