Are Compact Fluorescent Lightbulbs Dangerous?

Compact fluorescent lightbulbs contain a minuscule amount of mercury, and you can't safely ignore potential contact with it


On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.


Lightbulbs break all the time. So why would a single broken bulb in a Maine household trigger the state's Department of Environmental Protection to refer the homeowner to a decontaminator?

The answer lies in the type of bulb that broke—a compact fluorescent lightbulb—and what was inside that bulb. Compact fluorescents, like their tubular fluorescent precursors, contain a small amount of mercury—typically around five milligrams. Mercury is essential to a fluorescent bulb's ability to emit light; no other element has proved as efficient.

As effective as it is at enabling white light, however, mercury—sometimes called quicksilver—is also highly toxic. It is especially harmful to the brains of both fetuses and children. That's why officials have curtailed or banned its use in applications from thermometers to automotive and thermostat switches. (A single thermostat switch, still common in many homes, may contain 3,000 milligrams (0.1 ounce) of mercury, or as much as 600 compact fluorescents.)

The problem comes when a bulb breaks. Mercury escapes as vapor that can be inhaled and as a fine powder that can settle into carpet and other textiles. At least one case of mercury poisoning has been linked to fluorescents: A 1987 article in Pediatrics describes a 23-month-old who suffered weight loss and severe rashes after a carton of eight-foot (2.4-meter) tubular bulbs broke in a play area.

State and federal government agencies say that breakages, though deserving of caution, can usually be cleaned up inexpensively with household goods. (In the Maine case, the state acknowledges providing the referral but insists the homeowner was informed that such a step was unnecessary.)

Jim Berlow, director of the U.S. Environmental Protection Agency's (EPA) Hazardous Waste Minimization and Management Division, recommends starting by opening the windows and stepping outside. "Any problems at all frequently are handled for the most part by quickly ventilating the room," he says. "Get all the people and pets out of the room for 15 minutes and let the room air out. If you have a central heating system or an HVAC [heating, ventilating and air-conditioning] system, you don't want it sucking the fumes around, so shut that down."

The important thing is not to touch the heavy metal. After airing out the room, the larger pieces of the bulb should be scooped off hard surfaces with stiff paper or cardboard or picked up off carpeted surfaces with gloves to avoid contact. Use sticky tape or duct tape to pick up smaller fragments; then, on hard surfaces, wipe down the area with a damp paper towel or a wet wipe. All materials should be placed in a sealable plastic bag or, even better, in a glass jar with a metal lid.

"If it gets in the jar, that's pretty good containment," Berlow states. "We've found that the plastic bags actually don't contain any mercury fumes, so absolutely, if you've got the plastic bag, get it outside when you're done." Vacuums or brooms should generally be avoided, as they can spread mercury to other parts of the house.

Intact bulbs can be a headache to dispose of, too. In many locales it is illegal to throw fluorescents out with regular garbage, but the closest recycling or take-back facility may be miles away. (And, given the number of bottles and cans that end up in landfills despite the prevalence of curbside recycling programs, it seems likely that any barrier to recycling will make for relatively low reclamation rates; in 2004 the Association of Lighting and Mercury Recyclers estimated a residential mercury bulb recycling rate of 2 percent.) Many municipal waste facilities and some vendors accept fluorescents; the EPA and Earth 911 maintain online directories of collection sites. Among major retailers of fluorescents, IKEA offers to take back compact fluorescent bulbs in its stores free of charge.

"Our first preference is not to see them go into landfills," Berlow says. "Recycling really closes the loop on this as best we can right now. But on the other hand, we also don't see huge risks from them going into landfills, either."

And compact fluorescent bulbs actually reduce the mercury pollution from the single largest U.S. source: coal-fired power plants. "Probably the most important thing that people need to connect with compact fluorescents is that they save significant quantities of energy," Berlow adds. "We're talking about two thirds to three quarters of the energy associated with lighting being reduced."

James Dakin, senior consulting engineer at GE Lighting in Cleveland, says that a mercury-free lighting replacement may be in the works: light-emitting diodes (LEDs) are advancing rapidly. "LEDs are perhaps the most promising mercury-free alternative," he says, "but they currently fall far short in the overall efficiency/color/cost trade-off."

But for as long as fluorescents reign, don't look for a mercury phaseout. "Lots of other atoms and molecules have been investigated," Dakin explains, "but nobody has found anything as practical and efficient as mercury."

It’s Time to Stand Up for Science

If you enjoyed this article, I’d like to ask for your support. Scientific American has served as an advocate for science and industry for 180 years, and right now may be the most critical moment in that two-century history.

I’ve been a Scientific American subscriber since I was 12 years old, and it helped shape the way I look at the world. SciAm always educates and delights me, and inspires a sense of awe for our vast, beautiful universe. I hope it does that for you, too.

If you subscribe to Scientific American, you help ensure that our coverage is centered on meaningful research and discovery; that we have the resources to report on the decisions that threaten labs across the U.S.; and that we support both budding and working scientists at a time when the value of science itself too often goes unrecognized.

In return, you get essential news, captivating podcasts, brilliant infographics, can't-miss newsletters, must-watch videos, challenging games, and the science world's best writing and reporting. You can even gift someone a subscription.

There has never been a more important time for us to stand up and show why science matters. I hope you’ll support us in that mission.

Thank you,

David M. Ewalt, Editor in Chief, Scientific American

Subscribe