CFL bulbs contain an very small amount of mercury; about 1/100 the amount in a household thermometer. An unbroken CFL doesn't pose a health concern. However, expended CFL's should be disposed of properly, just like household hazardous waste such as paint and batteries.
If a CFL bulb breaks:
- Don't inhale the vapor.
- Don't use a vacuum.
- Sweep the pieces together with a brush or broom.
- Clean up glass with a wet rag or towel and place the towel, along with the pieces, into a sealed plastic bag.