[IKrines]

Woodshavings are somewhat safe, but it dust like crazy. I wouldn't recommend it for use indoor.
I had a horse that got respitatory disease by woodshavings and had to let down because of that.
Because a Hamster has so short life span, that is not very likely they would be affected by it, except for allergies. However the dust isn't good for your lungs and you have to consider your own health first.