Here is a severely unmaintained blue light bug zapper. You can't see it in this pic, but at the ends of the tube, upper and lower bulb (not shown), the tube filament melted some of the glass of the tube, both ends of all tubes, and is now open to atmosphere. It is also glowing like a good old incandescent bulb.
edit: if you look very carefully you can see the faint outline of a hole in the tube at the lower end of the tube in between the grid bars.