I heard that CFL bulbs contain mercury and that mercury is dangerous and bad for the environment.  Why are you encouraging me to use these bulbs?  

CFL bulbs contain a small amount of mercury, which is an essential ingredient for the CFL bulbs to produce light. However, no mercury is released when the bulbs are in use and remain intact.

To put this into perspective, the amount of mercury sealed inside a CFL bulb is less than 5 milligrams, or roughly the amount that would cover the tip of a ballpoint pen. In comparison, older thermometers contain about 500 milligrams of mercury, or about the amount contained in 100 CFLs.

The environmental benefits of CFL bulbs significantly outweigh the use of comparable incandescent light bulbs because CFLs use less energy to create the same amount of light as incandescent bulbs, resulting in lower mercury and green house gas emissions. In fact, the use of CFLs, even considering the small amount of mercury contained in the bulb, results in about 35 percent lower mercury emissions when compared to the amount of energy required to power an incandescent light bulb for a similar period of time.

What should I do when CFLs stop working or break? 

Some day your CFL will burn out.  But don't toss it into the trash.

While CFLs may be accepted by some municipal landfills, they contain small amounts of mercury, which should be kept out of the waste environment.

The amount of mercury inside a CFL's glass tubing is about 5 milligrams - roughly equivalent to the tip of a ballpoint pen.  It would take more than 100 CFLs to equal the mercury content found in an older style glass mercury thermometer, still, it's important to dispose of CFLs responsibly.

With another Smart Idea, ComEd has partnered with the Illinois Environmental Protection Agency (IEPA) and ACE Hardware to recycle CFLs.  Bring your used CFLs to a participating ACE Hardware store  near you.  They will dispose of them in IEPA-approved recycling containers.

You can learn more about proper CFL disposal, or local facilities that will accept your bulbs, by visiting www.Earth911.org or calling (800) CLEAN-UP. 

Chicago customers can visit www.bluecartschicago.org or call the city’s Household Hazardous Waste Center (1120 N. Branch St.) at 312.744.1614.

On June 24, 2008, The Home Depot®, launched a national in-store CFL recycling program, free at all its locations.