Fluorescent Lamp Recycling - Mercury in Lamps

Mercury in Lamps

The 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. 99% of the mercury is typically contained in the phosphor, especially on lamps that are near their end of life.