You could staple up some paper (but it should not be coated so it was a vapor barrier) to help contain the fiberglass dust. Something like Tyvek would work. It wouldn't trap moisture, but would contain the dust and is fairly strong to boot. Tyvek, and similar products, will stop liquid water, but pass moisture vapor. If you can get a deal on landscaping cloth (maybe not the right name?) it might cost less. This stuff is used under the mulch to help keep weeds down, but passes moisture. Another advantage of something like Tyvek is the white will tend to brighten the basement.