The fleece jackets he's talking about are all synthetic and they burn up/melt FAST. These things are popular and cheap, but don't ever wear one around the campfire (or, like we've found, while smoking). Wool and cotton are more flame resistant than synthetics used in clothing, but not quite as flame resistant as your skin. You can always check in with those people that do all the fire stuff ( like these
http://www.firefootbag.com/faq.html http://www.templeofpoi.com/poi/fire/safety.php ) and they should know - they say cotton, denim, leather, wool, etc, natural materials.