Most fluorescent lightbulbs contain around 5 mg of mercury vapor within them. Higher wattage fluorescent lightbulbs can contain more than 5 mg of mercury.
Mercury in any form is toxic. Ingesting, inhaling or handling mercury in any way can lead to serious side effects. Overexposure to mercury can facilitate neuromuscular changes like muscle atrophy, nerve response changes and may even cause death.
Mercury is an easily recyclable material. Fluorescent lightbulbs that are no longer in working order should be taken to a facility that can properly dispose of the lightbulb.
Because of the risks involved in handling fluorescent lightbulbs, they should only be changed and maintained by adults.
In cases where a fluorescent bulb breaks, a window should be opened immediately and everybody in the the room should leave for around fifteen minutes to let the mercury dissipate. A wet rag should be used to clean up the broken bulb.