CFL bulb’s contain mercury.
The good people at the Mercury Policy Project have posted a pdf report on how to manage those nasty CFL bulb accidents. We love item 2 — keep PEOPLE away from the breakage — so then, how does a person clean it up? Of course, if a good old incandescent bulb breaks, you just sweep it into the trash. That’s why we’re stocking up on incandescents before they disappear. — PID
• Do not use a vacuum cleaner to clean up the breakage. This will spread the mercury vapor and dust throughout the area and could potentially contaminate the vacuum.
• Keep people and pets away from the breakage until the clean-up is complete.