While mercury in various solid and liquid forms has to be used to make all fluorescent lights (including energy saving light bulbs - or CFLs) work properly, the mercury does not have to be used in its most dangerous liquid form. It can work just as well in a solid amalgam form combined with other elements. Using amalgam based CFLs is much safer, and environmentally friendlier.
Megaman - one of the world's largest manufacturers of energy saving light bulbs - has carried out exhaustive research into what happens when different types of low energy bulbs get broken in a confined space. While those types – including its own products - which use a safe form of amalgam – are safe when broken, those which contain liquid mercury can release mercury vapour in concentrations which far exceed internationally agreed safety limits.
The safe disposal of old or broken lamps and the potential effects on the environment are major concerns. All low energy bulbs lamps now have to be disposed of in recognised recycling points but it is a fact that many lamps containing liquid mercury are broken in the process, allowing mercury vapour to escape into the environment. In contrast, bulbs containing mercury in its solid amalgam form are quite stable, safe and minimise environmental pollution.
Technical white paper on use of amalgam in low energy light bulbs: