How much mercury is in one CFL?
The amount of mercury in a typical compact fluorescent lamp is approximately 5 milligrams (mg), barely enough to cover the tip of a ballpoint pen. To ensure that the amount stays this small, NEMA members agreed in April 2007 to a maximum mercury content of 5 mg in CFLs up to 25W, and 6 mg in CFLs with higher wattages. This commitment represents a ceiling—the actual average is estimated to be about 3–4 mg as manufacturers continue to design lower mercury versions. By comparison, an oral mercury thermometer contains 500 mg to 1 gram of mercury—or 100 to 200 times more than a CFL.
