it says that because flannel for childrens pj's have to have a chemical added to the fabric making it flame-retardant...it's the (stupid) law. and what is really dumb about it is ... the stuff they have to add washes out and is in-effective after 20 washes or so...i know my kids loved their flannel jammies and wore them lots more than 20 times. so...i use any fabric i want when i make clothes...there are no laws that say you can not make pj's out of anything you want...but you can not sell them if they do not have the flame-retardant fabric.