First, to answer your question, I believe that most people would say that it is a-ok for snakes. But, I had some questions about this myself, and ultimately decided not to use it.

My biggest concern is that the stuff is made from "reclaimed" cellulose, whatever that is. Anyone who has had issues with indoor mold knows that mold will grow/feed on just about and damp, cellulose-based material (wood, drywall, ceiling tiles... you name it). I was very concerned that keeping 50-60% humidity in an enclosed space filled with mold food had the potential to cause some serious mold growth. If nothing else, moe frequent and thurough cleaning would be neccessary.