i had one go "pop" and start smoking last night, glad i was home when it happened. ive had ballasts do that here at work but generally the bulbs start flashing and such and their is some humming before they blow. you normally have plenty of warning but this one at home was fine as near as i could tell, i was messing with the plants under it about a half hour before it popped a couple times and smoked and all looked fine up until that point.