Compact fluorescent light bulbs or “twisties” are commonplace. People are enjoying the savings from these products and have learned to modify their expectations of the light colour produced by these bulbs.
The Electrical Safety Authority (ESA) has received numerous inquiries about this blackening from concerned consumers.
When a incandescent lightbulb (traditional bulb) dies, it usually pops with a quick flash of light when you turn it on. When twisties come to the end of their useable lifespan, how they expire can vary depending on the manufacturer of the twistie, and on the type and location of the lighting fixture being used. When CFLs fail, they may emit smoke, an odour, or a popping sound. The plastic base may become discoloured, charred or deformed. Certification agencies have advised that this failure does not present a shock or fire hazard for approved products.
But they do say that when you see this discolouration, it is time to replace it.