I'm not sure, but I think yes a possible fire hazard if it breaks/overheats or something... or if easy to burn curtains get too close or something. But that's why you don't get the homemade lava lamps because you never know if the mixture is good or not... where the name brand ones should have a good mixture since they're sold and tested so many... so hopefully less likely to overheat...
surprisingly entertaining to watch
check out my pics on the question I asked!
http://www.sodahead.com/fun/l...