Compact Fluorescents and Mercury
Debunking some common CFL myths
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Compact fluorescent lights (CFLs) have long been known for their efficiency. More recently, they’ve been gaining favor with technological advances that make them an excellent substitute for incandescent lights. But public concern over mercury has also stirred up some controversy. This page outlines the reasons why using CFLs is good:
- Because they save energy, they cause less mercury to escape into the atmosphere from coal-fired power plants than incandescent lights
- The mercury housed in the lamp is in a liquid form and is most dangerous if it becomes vaporized.
CFLs contain less mercury than other household items
There is far less mercury in a CFL than in other household items.
| Item | Mercury amount |
| CFLs | 5 mg |
| Button cell battery | 7 mg |
| Thermometers | 500 mg |
| Old thermostats | 3,000 mg |
CFLs reduce atmospheric mercury pollution
Because about 50 percent of the country's power comes from coal-fired power plants, using CFLs actually prevents mercury from being released into the air by power plants. A power plant emits about 10 mg of mercury to produce the electricity needed to run an incandescent bulb, compared to only 2.4 mg of mercury to run a CFL for the same amount of time.
If you break a light, follow these tips to play it safe
1) Open nearby windows to disperse any vapor that may escape.
2) Wipe the area with a damp, disposable paper towel to pick up all glass fragments. Do not use a vacuum, broom or your hands.
3) Place all fragments in a sealed plastic bag and take to the nearest CFL recycling center.
Dispose of your used up CFLs properly
Because CFLs contain mercury, they should not be thrown out with the regular trash. CFLs in landfills are likely to break and release mercury into the environment. Be sure to recycle your old CFLs. Go to lamprecycle.org or earth911.org for more information about recycling areas near you.
Why CFLs need mercury
CFLs produce light differently than traditional bulbs.
Incandescent bulbs are tiny heaters: When you flip on a light switch, electric current heats up the metal coil inside the glass bulb until the filament burns so hot that it produces white light.
Compact fluorescent lights are gas charge lamps. That means they require an inert gas, which is mercury in the case of CFLs, to produce ultraviolet light. Phosophor coating on the inside of the glass illuminates this invisible ultraviolet light into light that we can see.
More on mercury and CFLs
- Mercury Risk in CFLs: The Facts - Our chief health scientist, Dr. John Balbus, gives details about why you shouldn't worry when a CFL breaks
- Mercury Poisoning from Light Bulbs? - Despite alarming news reports, we explain what to expect from a CFL break
- EPA's Frequently Asked Questions: Information on CFLs and Mercury [PDF]
- NEMA Voluntary Commitment on Mercury in CFLs - A number of CFL manufacturers are reducing the amount of mercury in their lights
- EPA's list of products containing mercury and recommended dispoal options.
More information on CFLs
- CFLs last longer in lamps that are left on for at least three hours.
- More CFL tips
- A note on light-sensitivity from our chief health scientist, Dr. John Balbus: All patients with lupus erythematosus or other conditions resulting in severe photosensitivity should consult with their physician regarding ultraviolet light exposure from compact fluorescent bulbs.
Posted: 22-Aug-2007; Updated: 12-Mar-2008
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