Answer:
No, Fuller's Earth isn't toxic to pets. Specifically, it's a safe, non-toxic, naturally occurring clay that's a popular litter choice by kittens and cats. It's famous for its ability to absorb and deodorize. Additionally, it offers the attraction of the natural colors of the earth from which it comes.
It isn't just the cats that like Fuller's Earth. Domestic dogs, cats and birds find Fuller's Earth a safe, non-toxic, fun way of getting clean through a dust bath.