If I had to guess, it sounds like the "outer vacuum" jacket of the bulb cracked inside the base. Did the bulb "hiss" after the noise? Was the smoke inside the bulb?

I've intentionally busted some old bulbs just for fun. You would notice the inner "tube" is the actual bulb and the outer glass of the bulb is just a jacket. That outer bulb seems to either be under vacuum and/or charged with an inert gas. You could break away that outer bulb and the inner "tube" would still work although it would be very hot and exposed to the atmosphere. I don't know if they do this so the inner bulb won't burst or burn out prolly?

I can say I would not risk using a bulb that could possibly explode or leak some possible mercury vapors. I'd buy a new bulb(s) and return this one.
Ocotillo Reviewed by Ocotillo on . Bulb problems I have a question about my HPS bulb.. i just recievied it in the mall today and went to turn it on to make sure it worked and everything was fine until i went to unscrew it and it made a pop noise then started to smoke the light stayed on and seems like it still works but there is a little piece moving around inside then bulb its self..... Any suggestions on what happen ??? Rating: 5