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Mercury Safety
All fluorescent lamps contain a small amount of elemental mercury (Hg), also known as quicksilver. When lamps are cold, some of the mercury in the lamp is in liquid form, but while the lamp is operating, or when the lamp is hot, most of the mercury is in a gaseous or vapor form.
Mercury vapor is a highly toxic substance, with an "extreme" rating as a poison. Even in liquid form, contact with mercury is considered life-threatening or a "severe" risk to health. Mercury can cause severe respiratory tract damage, brain damage, kidney damage, central nervous system damage, and many other serious medical conditions even for extremely small doses.
Many years ago, hat makers used mercury to tan the animal pelts used in hats, and the exposure to mercury gradually caused mental and nervous disorders, frequently mistaken for insanity. This mercury exposure is precisely what created the old saying "Mad as a hatter".
Although the amount of mercury in each fluorescent lamp is small, it is always important to avoid breaking fluorescent lamps, and that the unbroken lamps be delivered to a hazardous waste handler. Never EVER place fluorescent lamps in trash compactors or incinerators, since this will release the mercury and contaminate the surrounding area. Liquid mercury will not burn, but instead becomes a vapor when heated. It eventually cools and condenses back to a liquid form, spreading the contamination to larger areas.
Businesses, schools and other large commercial facilities that replace hundreds or thousands of fluorescent lamps each year are particularly at risk of creating areas of significant mercury contamination due to improper handling of lamps.
If not properly disposed, mercury can contaminate buildings, landfills, lakes, animals, fish, birds, humans, crops and rivers. In the United States, the Environmental Protection Agency finally ordered waste handlers to treat fluorescent lamps as hazardous waste. With such a classification, fluorescent lamps are not to be sent to landfills, but instead are to be sent to recycling centers that break the lamps under special conditions and safely recover the mercury.
Depending on the level of compliance with the EPA rules in your area, this recovery may or may not be done. Where I live, trash collectors typically throw fluorescent lamps into the general trash truck, which compacts them, contaminating the trucks, the landfill and the areas where the trucks operate.
With smaller fluorescent lamps on the market, it is also becoming more difficult for waste handlers to detect whether any fluorescent lamps are present in a given load of waste. The screw-in compact fluorescent lamps sold today are too easily placed in general household waste, making their detection extremely difficult.
Consumer awareness of the need to handle burned-out fluorescent lamps with the same care required for old storage batteries, old paints, pesticides and used motor oil remains the first line of defense in controlling this source of mercury contamination. While many municipalities do remind residents via newspapers and monthly bill inserts of the urgent need to not put batteries, old paint, pesticides and used motor oil into general trash, fluorescent lamps are habitually forgotten. These consumer notifications need to be updated.
However, that improved information won't do the job alone, as cities and other waste collectors need to take positive steps to make proper disposal of fluorescent lamps and these other items extremely simple. Otherwise, these items will end up in the general trash, even if the residents have to break fluorescent lamps into small sections (potentially contaminating their property), all in order to hide the old lamps in the trash bags or bins.
Where I live, residents that want to do the right thing are currently expected to drive up to 30 miles to reach a single hazardous waste collection point for the entire county, all just to properly dispose of these items. That level of inconvenience is just not acceptable to the general public, and so the vast majority of citizens dispose of these hazardous items in improper ways.
Some motivated trash haulers have added "Bad Bins" to their collection trucks, where they can store most of these hazardous items collected in residential neighborhoods, and then keep them separate from the general trash. Typically, tires are not taken by this method due to their bulk, but batteries, fluorescent lamps, motor oil, old paint and pesticides are. By far, these extra bins (sometimes simply welded-on to standard trucks by the local waste hauler or are really large canvas and plastic-lined bags that are slung on the side of trucks) are the most effective way I have seen of obtaining residential cooperation with disposal of these hazardous items, by allowing them to be picked-up at the curb.
In recent years, the EPA also ordered fluorescent lamp makers to reduce the amount of mercury in each lamp. For some makers, this wasn't a problem since they were putting more mercury in each lamp than was needed, or the manufacturer was able to switch to more sensitive phosphors that needed less ultraviolet light to produce the same amount of visible light. Other makers mixed other compounds with the mercury that supposedly compensate for the lower amount of mercury. However, some organizations have reported that some of these compounds are actually there only to deceive EPA instruments that are trying to measure how much mercury is present and that these other compounds do nothing else.
Because mercury will be released if a fluorescent lamp is broken, it is important to install fixtures in areas where the lamps are not likely to be broken. Fixtures in areas close to the ground or in areas with moving equipment should use metal or plastic shields to protect the lamp from being broken.
A few vendors sell fluorescent lamps that are coated with a strong plastic. If something hits and breaks the lamp, the glass breaks but the plastic holds all the glass and mercury inside, preventing the release of glass or mercury. These lamps typically cost two or three times as much as normal lamps, but in areas where breakage risk is high, the additional cost may be worth it, and some insurance companies now insist on such measures to reduce the risk of claims.
http://nemesis.lonestar.org/reference/electricity/fluorescent/safety.html