CFL bulbs contain about 4 milligrams of mercury, although in some new ones it's as little as 1.4 milligrams. That compares with 500 milligrams in old-fashioned thermometers. The mercury is harmless if it's inside the bulb, but it will get released as a gas if the bulb shatters. Should one break on your hard kitchen floor, for instance, you don't have to call the local hazmat unit. Just open the windows, and leave the area for a minimum of 15 minutes—typically enough time for the mercury vapor to either exit the house or disperse to a harmless level. Then use a piece of cardboard to scoop the debris into a Ziploc bag and bring it to a recycling facility that accepts "universal waste." Be sure to get every bit of broken glass because it can be coated with trace amounts of mercury. Log onto EPA.gov
for more cleanup tips.