Gardening with Tracey Fitzgibbon
Given the toxicity of mercury, why would light-bulb manufacturers have chosen to use it in the CFL light bulbs that replaced incandescents?
It’s kind of funny how things we didn’t even know enough to worry about a few years ago now have us donning Hazmat suits.
So let me ask you this: Do you have any of those long fluorescent light tubes in your house? Did you know there’s mercury in those things — possibly two or three times more than in these newer bulbs? Have you ever worried about it before? Probably not.
Compact fluorescent lights, or CFLs, are simply those oldfashioned tubes repackaged for a new purpose — to replace inefficient incandescents while saving energy. They work the same way: Instead of electricity heating up a wire that glows, the current in fluorescents is driven through a tube containing argon and a tiny bit of mercury vapor. This generates invisible ultraviolet light, which, in turn, excites a coating (phosphor) on the inside of the tube, which produces the light we see.
As for the mercury, you just can’t make fluorescent bulb without it, the experts say.
“At present, it is scientifically and technically impossible to produce mercury-free compact fluorescent lamps,” according to a report by Europe’s Scientific Committee on Health and Scientific Risks. “But new technologies can reduce the amount of mercury contained, and the authorized content will be gradually lowered.”
According to a 2008 article in Environmental Health Perspectives, CFLs typically contain from 3 to 5 milligrams of mercury. Moreover, a 2011 study found that if you break one, only a tiny fraction of that mercury will escape even if you don’t clean it up for 24 hours. As a result, these researchers found it could take weeks for the levels of mercury vapor in the room to reach a point that might be hazardous to a child.
Even more good news: Some lightbulb makers have dropped the amount of mercury to as little as 1.4 milligrams per bulb, compared to as much as 8 milligrams in those longer fluorescent tubes. (There are more than 28,000 milligrams in an ounce.)
And here’s the real kicker: The electricity required to power one of those old 60-watt incandescent bulbs over its lifetime would require a coal-fired generating plant to release an estimated 4.4 milligrams of mercury into the atmosphere, much more than a broken CFL bulb. By comparison, the electricity required to power a 13-watt CFL bulb over an 8,000-hour lifetime releases about 1 milligram of mercury into the atmosphere, again assuming that coal supplies about 40 percent of that electricity (the national average as of 2014).
If you do break one, there’s no need to panic. First, leave the room and air it out for five to 10 minutes. Then, scoop up the waste with stiff paper or cardboard, use sticky tape to pick up remaining residue and put it all in a sealable glass jar if possible. (Do not vacuum.) If practical, continue to air out the room and leave the HVAC system off for several hours.
Recycle burned-out but intact CFLs at a home improvement store like Home Depot or Lowe’s.