For years, consumers have been urged to switch to compact fluorescent lights, or CFLs, which use about one-quarter of the electricity of incandescent bulbs. But CFLs come with a health risk if they're broken: They contain small amounts of mercury, a neurotoxin that can be particularly harmful to pregnant women and children.
With sales of CFLs now reaching about 400 million a year in the United States, according to the federal Environmental Protection Agency, concerns over rising mercury levels have grown because many of the lights end up in landfills.
"It's a public health issue and an environmental mess if they are not disposed of properly," said Rob D'Arcy, the hazardous materials program manager for Santa Clara County, Calif.
California, Florida and several other states ban disposal of CFLs in the trash because they could contaminate landfills. But there's little enforcement.
Some local governments encourage consumers to recycle the bulbs on household hazardous waste collection days, but no one monitors how successful those voluntary efforts have been. Many fear that the vast majority of CFLs still end up at the bottom of the kitchen trash can.
CFLs contain an average of 5 milligrams of mercury sealed within glass tubing. That's far less than watch batteries, dental fillings and older thermometers, but still enough to warrant special handling.
If a fluorescent bulb breaks in your house, the EPA advises consumers to have all people and pets vacate the room, open windows for at least 15 minutes and carefully scoop up any broken fragments into a glass jar with a metal lid. Any heating or air-conditioning should be turned off before cleanup.
No one has called for CFLs to be banned because, on balance, they offer a wealth of environmental and energy-saving benefits. Coal-fired power plants are the largest source of mercury emissions in the air, so using the longer-lasting and more efficient CFLs is still a better deal for the planet.
Environmental groups such as the Natural Resources Defense Council have taken a close look at the CFL safety issue and have concluded that the energy savings exceed the dangers posed by the mercury the bulbs contain.
"The quantity of mercury contained in the bulb, and the opportunity to be exposed to the mercury, is quite small," the NRDC said in a May 2008 policy paper.
The ultimate solution for disposal of CFLs may come with further technological innovation. Many lighting experts see CFLs as a largely transitional product that will be replaced with LEDs, or light-emitting diodes, once volume production drives down costs. LEDs are considered more durable than incandescent bulbs or CFLs. And, unlike CFLs, LEDs don't contain mercury or require time to warm up.