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May. 2nd, 2007
Mercury in Compact Fluorescent Lights
May. 2nd, 2007 03:05 pmThere's been a bit of a fluster lately about the mercury in CFL bulbs. Some facts to counter the hysteria.
A) *All* fluorescent bulbs contain mercury. It is essential for their function. Modern CFL units have a very small amount; one comparison I read is that a typical bulb has about as much mercury as you'd get in forty cans of tuna.
B) While incandescent bulbs do not contain mercury, many electrical power plants exhaust mercury compounds into the air. If a CFL were broken at the end of a typical service life the electricity saved by using it instead of a incandescent bulb for the same period would result in less mercury in the environment, in a less hazardous form.
C) Most of the mercury in a CFL is in the phosphor coating, and relatively stable. Most of the rest is liquid metal. Pure mercury in liquid form is actually close to harmless; it's mercury vapor and some of its compounds which cause problems. So if some liquid mercury is spilled *don't* use an electric sweeper. That could vaporize part of the liquid. Instead, ventilate the room for a while, then use a broom to sweep up any lamp debris. If you see mercury droplets use an eyedropper or similar implement to collect the metal and put it in a sealed container.
Note that even these precautions are probably a bit of overkill. Most houses have a high enough air exchange rate that the debris from a single bulb would not produce a noticeable amount of mercury vapor even in a small room.
As for the problem of disposal of CFLs at the end of their lives, there are already programs underway in many places to collect fluorescent bulbs for recycling the mercury.
A) *All* fluorescent bulbs contain mercury. It is essential for their function. Modern CFL units have a very small amount; one comparison I read is that a typical bulb has about as much mercury as you'd get in forty cans of tuna.
B) While incandescent bulbs do not contain mercury, many electrical power plants exhaust mercury compounds into the air. If a CFL were broken at the end of a typical service life the electricity saved by using it instead of a incandescent bulb for the same period would result in less mercury in the environment, in a less hazardous form.
C) Most of the mercury in a CFL is in the phosphor coating, and relatively stable. Most of the rest is liquid metal. Pure mercury in liquid form is actually close to harmless; it's mercury vapor and some of its compounds which cause problems. So if some liquid mercury is spilled *don't* use an electric sweeper. That could vaporize part of the liquid. Instead, ventilate the room for a while, then use a broom to sweep up any lamp debris. If you see mercury droplets use an eyedropper or similar implement to collect the metal and put it in a sealed container.
Note that even these precautions are probably a bit of overkill. Most houses have a high enough air exchange rate that the debris from a single bulb would not produce a noticeable amount of mercury vapor even in a small room.
As for the problem of disposal of CFLs at the end of their lives, there are already programs underway in many places to collect fluorescent bulbs for recycling the mercury.