Phosphors
Lamps made up to the 1940s used toxic beryllium compounds, which were implicated in the deaths of factory workers. However, it is very unlikely that one would encounter any such lamps.
Formerly, toxic materials such as beryllium, arsenic, cadmium, and thallium were used in phosphor manufacture. Modern halophosphate phosphors resemble the chemistry of tooth enamel. The rare-earth doped phosphors are not known to be harmful.
Read more about this topic: Fluorescent Lamp Recycling