What are the Connections between Mercury and CFLs?

Photo of different types of CFLs

Why use CFLs if they contain mercury?

  • Small amounts of mercury can be released into the environment when CFLs break, or if they are improperly disposed of at the end of their useful lives.
  • Despite these emissions, the use of CFLs actually helps reduce total mercury emissions in the U.S. because of their significant energy savings.  Using energy-saving CFLs reduces demand for electricity, which in turn reduces the amount of coal burned by power plants, which reduces emissions of mercury when the coal is burned.

Saving energy helps you save money on utility bills.  You can learn more about how how CFLs work, and CFLs and mercury, from EnergyStar.gov.

Connections between Mercury and CFLs

1. Using CFLs (and other fluorescent bulbs) reduces the amount of mercury released into the environment

  • Mercury is found in many rocks including coal. When coal is burned at a utility power plant to produce electricity, mercury is released into the environment.
  • In the U.S., burning coal at power plants results in about half of all mercury emissions from man-made sources (source: Section 2.6 of the 2011 National Emissions Inventory, version 1 (November 2013) of the Technical Support Document (PDF)).
  • Using energy-efficient CFLs reduces demand for power, which in turn reduces the amount of coal burned by power plants and the amount of mercury emitted when coal is burned.

2. CFLs contain very small amounts of mercury

  • Mercury, an essential part of CFLs, allows a bulb to be an efficient light source.
  • On average, CFLs contain about four milligrams of mercury sealed within the glass tubing. By comparison, older thermometers contain about 500 milligrams of mercury – an amount equal to the mercury in over 100 CFLs.
  • Manufacturers of fluorescent lighting products are working to reduce the amount of mercury content in CFLs.
  • No mercury is released when the bulbs are intact (i.e., not broken) or in use, but CFLs can release mercury vapor when broken.