Mercury in lampsThe amount of mercury in a fluorescent lamp varies from 3 to 46 mg, depending on lamp size and age. Newer lamps contain less mercury and the 3–4 mg versions are sold as low-mercury types. A typical 2006-era 4 ft (122 cm) T-12 fluorescent lamp (i.e., F32T12) contains about 12 milligrams of mercury. In early 2007, the National Electrical Manufacturers Association in the US announced that "Under the voluntary commitment, effective April 15, 2007, participating manufacturers will cap the total mercury content in CFLs under 25 watts at 5 milligrams (mg) per unit. CFLs that use 25 to 40 watts of electricity will have total mercury content capped at 6 mg per unit."
Only a few tenths of a milligram of mercury are required to maintain the vapor, but lamps must include more mercury to compensate for the part of mercury absorbed by internal parts of the lamp and no longer available to maintain the arc. Manufacturing processes have been improved to reduce the handling of liquid mercury during manufacture and improve accuracy of mercury dosing.
Mercury-free discharge lamps have considerably lower production of visible light, about half; mercury remains an essential component of fluorescent lamps.
A broken fluorescent tube will release its mercury content. Safe cleanup of broken fluorescent bulbs differs from cleanup of conventional broken glass or incandescent bulbs.[how?] 99% of the mercury is typically contained in the phosphor, especially on lamps that are near their end of life.
PhosphorsLamps 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.
Mercury containmentWhen discarding a fluorescent tube, the main concern is the mercury, which is an important pollutant. One way to avoid releasing mercury into the environment is to combine it with sulfur to form mercury sulfide, which is insoluble in water. One advantage of sulfur is its low cost. The reaction is shown with the equation:
Hg + S → HgS
The easiest way to combine sulfur and mercury is to cover a group of fluorescent tubes with sulfur dust and break them; when the glass is put into a bag to continue with the reaction, the mercury will combine with sulfur without any other action. The glass can be recycled where an appropriate facility exists. A quantity of 25 kg of dust sulfur is enough for 1000 tubes.
Disposal methodsThe disposal of phosphor and mercury toxins from spent tubes can be an environmental hazard. Governmental regulations in many areas require special disposal of fluorescent lamps separate from general and household wastes. For large commercial or industrial users of fluorescent lights, recycling services are available in many nations, and may be required by regulation. In some areas, recycling is also available to consumers.
Spent fluorescent lamps are typically packaged prior to transport to a recycling facility in one of three ways: boxed for bulk pickup, using a prepaid lamp recycling box, or crushed for pickup. A fluorescent lamp crusher can attach directly to a disposal drum and contain dust and mercury vapor.  In some states, drum top crushers and self crushing lamps is not allowed. Minnesota Department of Health Drum Top Bulb Crusher Demonstration Disposal methods are regulated at both the state and federal level. Proper recycling of fluorescent lamps can reduce risk of human exposure to mercury. Companies that recycle spent fluorescent lamps include Air Cycle Corporation, Mercury Technologies of Minnesota, Inc., USA Lamp & Ballast Recycling, Inc, Waste Management, and Veolia.