Australia to ban incandescent lightbulbs.

However,

But there's another side to CFLs that could be not so environmentally friendly.

Electricity in an incandescent bulb runs through a filament causing it to glow. But in CFLs electricity ignites gas inside the bulb causing it to emit ultraviolet rays.

A small amount of mercury is required to help ignite that gas, and it's this mercury that's a known hazard.

The incandescent bulbs indirectly result in mercury releases to the environment too.

The life-cycle analysis found that when you consider the mercury produced from burning coal for electricity, the energy hungry incandescent bulbs contribute five times more mercury to the environment than CFLs do.

But most acknowledge that the issue of mercury is likely to be more significant as electricity generation gets cleaner and CFLs become more widespread.