are all/some treated with flame retardant? I have some conventional sheets that are 100% cotton, and can't find anything online about this (and don't have the package any more, but I don't remember it saying anything about it either way).
I don't think they are. I think if they were it would say so online- like when reading a description yk.
Anything you're not sure of, make sure you wash it five times on a hot setting in borax washing powder and you'll get rid of the antimony.
organic fitted crib sheets are not.