[Crystalroborovski]

I agree with drago, knowing what kind of wood the bedding is would be helpful. Sawdust itself is dangerous for hams, it's very fine particles that are easy to breath in and can cause bad respiratory issues. The only wood bedding that is safe is shredded aspen or aspen shavings (or cat litter wood pellets, though it isn't recommended as a substrate for the whole cage).