My roommate and I have set up a couple fairly strong black lights in our dorm room. They're forty watt fluorescent tubes about three feet tall, and look quite cool. However, we are both wondering whether there's any health risk associated with being exposed to the black lights for an extended period of time. They're the sort of light you purchase at a novelty store like Spencer's Gifts. I would expect that nothing sold under those circumstances would emit any significant radiation at potentially harmful wavelengths, but perhaps I'm too trusting. So, is there a health risk here?