The Fluorescent Lighting System

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Section 9: Fluorescent Lighting Safety

Although fluorescent lighting is an efficient source of light, it does have some safety issues. Understanding these issues can help guide the selection of the best types of fixture, lamp and location that can avoid many of these issues.

Electrical Safety

A general rule of thumb is that any fluorescent fixture that uses lamps longer than 24" or that is to be used outdoors or in damp, wet or high-humidity locations (like commercial kitchens) must have an electrical ground for the fixture and ballast.

All rapid start and instant start fixtures must have an electrical ground in order to operate properly.

In addition to the need for an electrical ground for the fixture to operate, 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. Fixtures should always be operated with all access covers installed and lamps fully seated in their sockets, and with proper fixture grounding when indicated.

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.

Integrated Ballast Overheat Safety

Fluorescent lamp ballasts can fail. Leaving burned-out lamps in the fixture, using the wrong size lamps, incorrect wiring, incorrect line voltage, operation at temperatures below or above the rated limits, power surges, and even the age can all cause a ballast to fail.

However, not all ballasts fail and stop functioning. Many overheat. Because a failing ballast can get extremely hot, it can become a fire hazard. All modern magnetic ballast designs have an internal temperature sensor that shuts the ballast off it gets too hot. In most designs, when the ballast cools off, the sensor will allow the ballast to turn back on. A fixture where some or all of the lamps shut off by themselves and later come back on is probably a fixture with a failing ballast.

Overheating magnetic ballasts may also leak. The coils of modern ballasts are embedded in tar, but if the ballast is overheating, this tar can melt and leak out of the ballast. If you see black tar leaking out the ballast, this indicates a problem that needs to be corrected. IF you see light-colored oil leaking, see the PCBs section below. If not, replace the ballast, and you can dissolve and remove any tar left on the fixture (or that leaked out of the fixture) with WD-40, wiping up the mixture with paper towels.

Electronic ballasts may state that they have "Inherent Overload Protection" or something similar. This means that because of the way the switching power supply inside the ballast works, it cannot overheat due to what the lamps are doing, even if the lamps are burned-out or not installed. However, any ballast can overheat due to incorrect wiring, a component failure, or a power surge. Electronic ballasts are supposed to all shut off when they fail, but some types of failure may prevent that shutdown.


Prior to the 1970s, some ballasts - particularly those used to control "High-Output" lamps - contained PCBs. PCBs were a group of compounds with electrical insulating properties, and were found in transformers and other electrical devices. PCBs are also carcinogens, and their use in electrical equipment has been banned since the 1970s, but a ballast made before this date could contain this compound. In these older ballast designs, the PCB compounds could leak out of a ballast if it is overheated or if the ballast case is physically damaged. Newer ballasts are usually marked "NO PCBs" to indicate that they don't contain these compounds even if older models from that manufacturer didn't have any PCBs either.

If a ballast is leaking a clear or light colored oil, it may indicate the presence of PCBs. If the model number and manufacturers name are still on the ballast, contact them and ask if the ballast contained PCBs. The call centers of all ballast manufacturers have the answer to this question for all of their older ballast models. In some companies, you will be transferred to the product safety group of that company who will assist you.

If you can't find out if the ballast contains PCBs or find out that it definitely does, wear gloves and clean up the oil with disposable towels. Then replace the ballast with a modern one. The clean-up materials, the old ballast and the gloves should be sent to a hazardous material handler for proper disposal.

If the ballast doesn't contain PCBs but is leaking, make sure that the correct lamps are being used, that the fixture is wired according to the diagram on the ballast, and that the ballast is correct for the local line voltage. Correct any of these things that are wrong, and then replace the ballast.

Breakage Safety

Fluorescent lamps have 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.

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.

If a fluorescent lamp breaks, there are numerous safety and cleanup issues, which are discussed in more detail in Appendix B.

There are numerous material safety sheets available on the Internet and directly from chemical companies that provide recommendations on how to deal with mercury spills. The procedures for handling mercury spills are constantly being refined, so seeking professional help to clean up a spill is advised since they will have the latest handling recommendations.

Short Wave Ultraviolet Light Safety

A long term hazard from fluorescent lighting is the shorter-wave ultraviolet light that escapes the lamp. No matter how well crafted, some short-wave ultraviolet light escapes from every fluorescent lamp made. (Even incandescent lamps produce a small amount of short-wave ultraviolet light.) Short-wave ultraviolet 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 ultraviolet light can also age or damage paper, fabrics and other materials.

In the early days of fluorescent lighting, this was quite a serious problem and ultraviolet emissions were a significant percentage of the total light produced. This caused a lot of conspiracy theories about the use of fluorescent lighting, many of which were as unfounded as the theories that surrounded the introduction of fluoridation to drinking water.

Fluorescent lamps tend to leak more short-wave ultraviolet light at the ends of the lamps, where the phosphor coating is frequently thinner and there is more high-energy activity, due of the presence of the cathodes inside each end of the lamp. Some fixtures actually block light from this part of the lamp, but this is likely just a lamp restraint, rather than being an attempt to block ultraviolet light from escaping out of the fixture.

Generally, fixtures with a plastic lens leak the smallest amount of ultraviolet 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 ultraviolet-absorbing sheeting applied to the lamps or the fixture lens to eliminate all ultraviolet light.

Related Topics

Appendix B: I Broke a Fluorescent Lamp. Now What? (HTML)

Section 10: Troubleshooting Fluorescent Lighting (HTML) [NEXT]

Return to The Fluorescent Lighting Reference Index (HTML)

[Copyright 2002,2003,2004,2005,2007 Frank Durda IV, All Rights Reserved.
Mirroring of any material on this site in any form is expressly prohibited.
The official web site for this material is:
Contact this address for use clearances: clearance at
Comments and queries to this address: web_reference at]

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