As far as I can tell from the information on the website and pictures of the packaging, they appear to be safe. Wood stove pellets by themselves are suitable for rabbits - the concern with ones marketed for stove purposes is if they have something like lighter fluid as an additive to help them catch fire. If they don't say that they do, I believe that you can be certain that they don't... but if you're worried, look for a customer service number for the company and call them to ask .
I would recommend finding a soft wood pellet instead, like pine or aspen(not cedar). Some hardwoods aren't good for rabbits, and I don't know that hardwood is the best for absorption either. Tractor supply/farm stores have equine wood pellet bedding that would be better to use.