Compact Fluorescent Lights (CFLs) along with more traditional fluorescent lamps are now being aggressively marketed as environmentally friendly due to their reduced electricity consumption. Indeed, widespread replacement of incandescent bulbs with CFLs will greatly reduce electricity demand; however, there are safety issues that ultimately contribute to making LED lighting the superior choice. Understanding fluorescent lighting risks can help ensure that fluorescent light bulbs are used and disposed of safely while explaining why LED lighting is the safest and most eco-friendly lighting choice in the long run.
Mercury
The most commonly cited fluorescent lighting hazard is mercury. Fluorescent and CFL bulbs contain a small amount of mercury and are identified with the elemental symbol Hg. When these bulbs 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 extremely toxic. Even in liquid form, contact with mercury is considered life-threatening or a "severe" risk to health. Even very small doses of mercury can cause severe respiratory tract damage, brain damage, kidney damage, central nervous system damage, and many other serious medical conditions.
CFLs average less than 4 milligrams of mercury, about the amount that would cover the tip of a ballpoint pen. By comparison, older thermometers contain about 500 milligrams, an amount equal to the mercury in 125 or more CFLs. Although the amount of mercury in each fluorescent lamp is small, it is always important to avoid breaking fluorescent lamps, and used bulbs must be delivered to a hazardous waste handler. Never place fluorescent lamps in trash compactors or incinerators, since this will release the mercury and contaminate the surrounding area.
Disposed of improperly, mercury can contaminate buildings, landfills, lakes, animals, fish, birds, humans, crops and rivers. In the US, the EPA has 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. Up to 95 percent of the mercury contained in CFLs can be recovered if the bulbs are recycled properly.
Mercury-containing lamps generated by households and small businesses are not always subject to legal restrictions regarding their disposal. State laws vary and some states, such as California, Maine, New Hampshire, Minnesota, Vermont and Massachusetts, prohibit all mercury-containing lamps, including CFLs, from being discarded in the solid waste stream. In addition, many local ordinances require recycling of mercury-containing products, including lighting. It is best to check with your municipality to understand whether there are local requirements addressing mercury-containing waste disposal.
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. If a fluorescent lamp breaks, there are numerous safety and cleanup issues which we discuss in more detail in the following section.
Breakage
Fluorescent lamps create several hazards if broken. Depending on the type, there may be a partial vacuum or the lamp may be under pressure. Breaking the glass can cause shrapnel injuries, along with the release of mercury and other hazardous compounds.
The biggest immediate injury threat from a broken lamp is from the phosphor-coated glass. If cut with fluorescent lamp glass, any phosphor that gets into the wound is likely to prevent blood clotting and will interfere with healing. Such injuries should be treated seriously and immediate medical attention should be obtained for people or pets that are cut. Medical personnel should be informed that the injuries were caused by a broken fluorescent lamp, and that mercury was present.
To minimize exposure to mercury vapor, EPA and other experts advise a few precautions. Children and pets should stay away from the area, and windows should be opened for at least 15 minutes so that vapors may disperse. Cleanup can be done by hand using disposable materials. Use rubber disposable gloves and scoop up the materials with stiff paper or cardboard. Use sticky tape to pick up small pieces and powder, clean the area with a damp paper towel, and dispose of the materials in an outside trash can. Never use a vacuum because this will only disperse the mercury vapor and leave particles trapped inside the cleaner bag.
Dimmers
Never use a CFL with a dimmer in the circuit (unless it is specifically made to work with dimmers), even if the dimmer is set at the maximum setting. Doing so places you at risk of fire and at the very least will dramatically shorten the life of the lamp and the dimmer. Also most photocells, motion sensors and electric timers are not designed to work with a CFL. Check with the manufacturer for the use of a CFL for these types of fixtures.
To use a CFL on a dimmer switch, you must buy a bulb that's specifically made to work with dimmers (check the package). GE makes a dimming compact fluorescent light bulb (called the Energy Smart Dimming Spirals®) that is specially designed for use with dimming switches. I don't recommend using regular compact fluorescent bulbs with dimming switches, since this can shorten bulb life. Using a regular compact fluorescent bulb with a dimmer will also nullify the bulb's warranty.
Finally, if a CFL bulb "buzzing" when it is installed in a fixture that is controlled by a dimmer switch, this is an indication that you have the wrong type of CFL bulb installed.
Electrical
Any fluorescent fixture that uses lamps longer than 24" or that is used outdoors or in a damp, wet, or high-humidity location must have an electrical ground for the fixture and ballast. All rapid-start and instant-start fluorescent fixtures must have an electrical ground in order to operate properly. Fixtures with longer lamps operate at higher voltages, with some fixtures having starting voltages across the lamp as high as 950 VAC. Voltages at this level represent a strong shock hazard and improperly grounded fixtures or direct contact with electrical connectors or other wiring can result in severe injury or death.
When servicing fluorescent fixtures and lamps, electrical power to the entire fixture should be disconnected. This is not always practical in situations where a large number of fixtures are controlled from the same power control (such as in open office areas). In these cases, insulating gloves and a nonmetallic ladder should be used if the fixtures must be serviced when power is present. This advice also applies when retrofitting a fluorescent fixture to mount LED tube lights.
Short-Wave Ultraviolet Light
A long-term hazard from fluorescent lighting is the shorter-wave ultraviolet (UV) light that escapes the lamp. No matter how well crafted, some short-wave ultraviolet light escapes from every fluorescent lamp made. Short-wave UV light is one of the damaging components of the suns rays that reach the surface of the Earth, which can directly damage organic tissue and trigger cancers. Short-wave UV light can also age or damage paper, fabrics and other materials.
Generally, fixtures with a plastic lens leak the smallest amount of UV light, mainly because most of the ultraviolet light gets absorbed in the plastic lens. Fluorescent lighting in museums, archival libraries and manufacturing "clean room" areas usually have UV-absorbing sheeting applied to the lamps or the fixture lens to eliminate all UV light. LED bulbs do not produce any UV light.
Flicker and Glare
Flicker and glare from fluorescent lights can also cause headaches and have been found to impact learning and ability to concentrate. Although humans cannot see fluorescent lights flicker, the sensory system in some individuals can somehow detect the flicker. Ever since fluorescent lighting was introduced in workplaces, there have been complaints about headaches, eye strain and general eye discomfort. These complaints have been associated with the light flicker from fluorescent lights. When compared to regular fluorescent lights with magnetic ballasts, the use of high frequency electronic ballasts fluorescent lights resulted in more than a 50% drop in complaints of eye strain and headaches. There tended to be fewer complaints of headaches among workers on higher floors compared to those closer to ground level; that is, workers exposed to more natural light experienced fewer health effects.
Long-term clinical studies that conclude fluorescent lighting in schools may be related to many academic and health problems. A 2006 study found that students in schools with natural light instead of fluorescent lighting had a 10% to 21% higher learning rate and higher test scores. Fluorescent lighting may trigger headaches, migraines and other physical symptoms. Many children have been mislabeled with learning disabilities, ADD/ADHD, reading problems and dyslexia all because of students having to work under fluorescent lights. With cool-white fluorescent lighting, some students demonstrated hyperactivity, fatigue, irritability, and attention deficits.
Lamps operating on alternating current (AC) electric systems produce light flickering at a frequency of 120 Hertz (Hz, cycles per second), twice the power line frequency of 60 Hz (50 Hz in many countries outside North America). Essentially, the power is turning on and off 120 times a second (actually the voltage varies from +120 volts to -120 volts, 60 times or cycles a second and is at zero volts twice in one cycle). People cannot notice the flicker in fluorescent lights that have a flicker rate of 120 cycles per second (or 120 Hz).
Flicker is usually a potential problem only with lighting that require the use of ballasts, like fluorescent lights. Incandescent lights usually do not cause a flicker problem since the light filaments generally do not cool quickly enough (and make the light dimmer) during the "off" time as the voltage changes in the AC power line. New, energy-efficient electronic ballasts take the 60 Hz power and convert it to voltages at a much higher frequency. The resulting flicker frequency is so high that the human eye cannot detect any fluctuation in the light intensity - essentially flicker-free. An added benefit is that electronic ballasts produce less hum than that emitted by other kinds of ballasts.
Manufacturers and regulators have taken steps to eliminate this problem with LED lights. In the US, the new Energy Star criteria for integrated LED replacement lamps include a requirement for 150 Hz operation (now being challenged by manufacturers who cite studies that 120 Hz is sufficient). The majority of low-frequency AC LED systems already operate in the rectified mode, which effectively doubles the luminous modulation frequency to 120Hz for 60Hz mains in the US. Despite many attempts, laboratory investigations have not found statistically significant evidence of luminous modulation with frequencies over 100Hz on human performance, health, or comfort.
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