I was thinking of lining the shelves with something, or setting something like tiles on them, so that they aren't a slatted surface for the hamster to walk on. Even if I left it as is, I think it'd be okay. There's not a very high risk of a limb getting caught; the slats are about 1 inch apart and thick enough enough for a hamster to get a grip and balance easily. A hamster could probably even squeeze its body between the slats if it wanted.
Sure, it's almost always cheaper and more economical to make your own. This shelf is fairly cheap though, and sometimes people don't want to make their own. I like having options, and I like having safe, affordable options that I can suggest to other people.
What I really liked was the size on this - it's only 11 inches high when assembled, and the footprint of it is about 25 x 12 inches. It could quite comfortably fit in a 40 gallon aquarium, and it looks like it'd be extremely useful and versatile. $15 for two levels that size is quite a bargain I'd say. Scratch that,
this one is slightly larger and costs less.
Thank you for the ideas and suggestions, AmityvilleHams. You seem pretty handy. I do have a handsaw, some dowels, and other materials laying around that I may just use for this purpose. I don't think it would be necessary to do anything to the wood, though. Honestly, I feel better leaving untreated wood untreated.
It says that the wood used for this shelf is "all natural" and that it has a "natural finish." People talk about sanding and treating it in the reviews, and customer service said it should not be put outside because it is not varnished. Customers also said there is no protective coating; it is bare, unfinished wood.
It does say the wood is pine. I've never actually heard of a hamster becoming ill or passing away by coming into contact with a natural, unshaved wood, including pine. I even used pine shavings for years back in the day with seemingly no problems. Is there evidence of this happening?
It doesn't say what kind of wood it is on a lot of items, regardless of what its marketed for. What kinds of wood should we avoid? This shelf looks like the same kind of wood a lot of pet items are made out of, and it also looks like the same kind a lot of dowels are made out of. Which, as far as I know, is usually pine or some other kind of soft wood.
For example,
this is made out of pine (I had to look in the questions),
this is made of pine, and
this item doesn't even say if it's wood or not. If you're worried about your hamster breaking legs in slats, stay away from that last one.
Chesca, thank you for the suggestion!