I'm another that likes natural fibers due to the fire risk. Granted, I'm married to a fireman but also am aware of the melting risks due to other influences. As well as having lived through a house fire as a child. I presently have a roll of W&N that I am (slowly) using up. After that will probably switch to Quilter's Dream 100% cotton. due to the enhanced drape.
Synthetic fibers melt to the skin - they do not burn. I will stick with 100% natural fibers - cotton; wool; silk.