CFLs have a coiled tube instead of the round bulb you see in old-style light bulbs (incandescent bulbs). They are like the long fluorescent light tubes you see in ceiling lights, but shrunk down and coiled up so they can replace incandescent bulbs.
In a CFL, an electric current is driven through a tube containing argon gas and a small amount of mercury vapor. This makes invisible ultraviolet (UV) light. The UV light hits a coating on the inside of the tube, which then gives off visible light.
CFLs use about 75 percent less energy than incandescent bulbs. Saving energy helps the environment. Using less energy means less greenhouse gases will get into the air.
Safely using and disposing of CFLs is very important to protecting our health and environment. Recycle spent CFLs to prevent mercury getting into the environment.
Towns, cities, and some stores collect CFLs for recycling.
CFLs contain a small amount of mercury sealed in the glass tube. When a CFL bulb breaks, some of this mercury gets into the air as vapor. The broken bulb can release mercury vapor until it is cleaned up and removed.
If a CFL gets broken, everyone needs to leave the room right away. Tell an adult about the broken CFL, so they can clean it up the right way.
Visit https://www.epa.gov/cfl/cflcleanup.html for more on CFL bulb cleanup.