As of late I've heard of a lot of people using organic topsoil as snake/reptile substrate, or using it in conjunction with something else (ex. cypress mulch, coco coir). One of the vet techs I work with recommended it and I plan on using it in a substrate mix for my ball python's new enclosure (although I'm sure it would be good for other snakes as well). I'd assume since it holds moisture so well without getting super damp and has such a small particle size that the risk of ingestion and inhalation would be minimal.
EDIT: I forgot to add that I usually try to feed my snake on top of his plastic hide so he doesn't swallow any substrate. My vet recommended I do that if I am not comfortable feeding him outside of his enclosure to minimize any risks.