CFLs are safe when used according to instructions. Yes, CFLs contain a very small amount of mercury sealed within the glass tubing - an average of 4 milligrams per light bulb, roughly equivalent in size to the point of a ball-point pen or less. By comparison, CFLs contain about 1/125th of the mercury that older thermometers contain. You can find out more information on the amount of mercury in bulbs at the ENERGY STAR® website
No mercury is released when the bulbs are intact. It is important to properly recycle used CFLs at a recycling center
near you to ensure safe disposal.
If a CFL breaks, follow the cleanup procedures outlined on the ENERGY STAR website