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Frequently Asked Questions About Compact Fluorescent Lamps


According to the US EPA and US DOE, Energy Star qualified compact fluorescent lamps (CFLs) use about 75 percent less energy than standard incandescent bulbs and last up to 10 times longer. As energy prices increase, CFLs have become increasingly popular as a means for businesses and homes to reduce lighting energy bills. This NEMA fact sheet answers some commonly asked questions about CFLs, including how they operate, the role that mercury plays in their efficient operation, and the importance of proper disposal.

Q: Are compact fluorescent lamps new?

Compact fluorescent lamps, also known as CFLs, are a type of fluorescent lighting; fluorescent lighting has been around since the 1940s. Tube-shaped “linear fluorescent” lamps have long been popular in business and commercial settings, as well as for household uses such as in garages, kitchens, and recreation rooms. Smaller, compact versions of fluorescent lamps, CFLs, first appeared in the 1980s. Due to design improvements, they are now widely available as an alternative to incandescent lamps for other areas of the home and for commercial applications.

Q: What function does mercury perform in fluorescent lighting?

A typical fluorescent lamp is composed of a phosphor coated glass tube with electrodes located at each end. A small amount of mercury is contained in this tube, partly in vapor form. When a voltage is applied, the electrodes energize the mercury vapor, causing it to emit ultraviolet (UV) energy. The phosphor coating absorbs the UV energy, causing the phosphor to glow or “fluoresce” and emit visible light. Without the mercury vapor to produce UV energy, there would be no useful amount of light. Manufacturers have tested virtually every other element on the periodic chart to find an acceptable, equally efficient substitute for mercury in fluorescent lamps, without success.

Q: How many CFLs are being sold?

According to estimates by the US EPA, total Energy Star® CFL sales for 2007 totaled approximately 290 million bulbs, nearly double the sales in 2006, and constituted nearly 20% of the screw-base light bulb market in the US. While the majority of CFLs are Energy Star compliant, some are not, which means actual total sales of CFLs in the US in 2007 was over 300 million. 

Q: How much mercury is in one CFL?

The amount of mercury in a typical compact fluorescent lamp is approximately 5 milligrams (mg), barely enough to cover the tip of a ballpoint pen. To ensure that the amount stays this small, NEMA members agreed in April 2007 to a maximum mercury content of 5 mg in CFLs up to 25W, and 6 mg in CFLs with higher wattages. This commitment represents a ceiling—the actual average is estimated to be about 3–4 mg as manufacturers continue to design lower mercury versions. By comparison, an oral mercury thermometer contains 500 mg to 1 gram of mercury—or 100 to 200 times more than a CFL.   

Q: How much mercury is in all light sources?

Industrial use of mercury has declined drastically in all sectors, including lighting, since the 1980s. As reflected in its report to the IMERC[1] database (a regional clearinghouse for information on mercury in products), the NEMA lamp section reported total mercury used in all light sources (i.e., fluorescent lamps and other mercury-added lights such as high intensity discharge) to be approximately 8 tons in 2004. This was one ton lower than the amount reported in 2001 despite an enormous increase in sales of CFLs over that period, and represents less than 10% of overall industrial consumption of mercury. The lighting sector falls well below other sources of industrial consumption, such as switches, measuring devices, and dental amalgam.

Q: Does mercury represent a threat to the environment?

Actually, the net environmental benefit of using CFLs to replace incandescent lamps is positive.  Reductions in mercury emissions from reduced power generation far outweigh mercury emissions from any type of lamp disposal activity. To minimize emissions from lamp disposal activities, NEMA recommends recycling CFLs and other fluorescent lamps, which is required by law in some states and local jurisdictions. NEMA is also working with US EPA, retailers and other groups to increase available recycling options.  Lamps that are not recycled typically end up in landfills and, to a lesser extent, household waste incinerators. Neither of these is a significant source of mercury emissions to the environment. Landfill emissions are extremely small and incinerators are tightly controlled by regulations established under the 1990 Clean Air Act amendments, which led to a 90+% drop in incinerator emissions over the subsequent decade. Emissions from lamp disposal activities pale in comparison with the volume of mercury emissions from coal-fired utilities, mining operations, and other major sources of mercury. So while mercury is an important environmental issue, lamps are a minor contributor to the problem, and, as discussed above, actually reduce overall mercury emissions to the environment. The US EPA, environmental advocacy groups, and energy efficiency groups are all aware of these facts, and all promote the use of CFLs as a preferred environmental option.

Q: What about recycling CFLs?

Recycling services are widely available for the business and commercial sectors and are becoming more and more accessible for households, depending on location. Retail chains such as Home Depot, Ikea, Ace Hardware, and Tru Value accept CFLs at an increasing number of their locations. In some states, utilities are administering collection programs using funds provided through ratepayer schedules. Meanwhile governments at all levels are convening stakeholder meetings and working groups to evaluate recycling solutions.  NEMA members are participating in several such efforts and continue to promote recycling through www.lamprecycle.org and company-specific efforts. In addition, the US EPA provides recycling information at the following Web site: www.epa.gov/bulbrecycling.

Q: What does federal law say about disposing CFLs?

Federal law classifies lamps that fail the “Toxicity Characteristic Leaching Procedure” (TCLP) as “Universal Waste.”  Lamps that fail this test must be specially handled and cannot be disposed along with ordinary garbage. The specific handling and disposal requirements are provided by the “Universal Waste” rule (UWR), which is much less stringent than the procedures applicable to full industrial hazardous wastes. The UWR is designed to control the management of widely prevalent, low-risk wastes and to facilitate recycling. It only applies to large generators of lamps, however, as households and “conditionally exempt small quantity generators” are exempt.  Lamp manufacturers have produced a number of lamp types that pass the TCLP test and thus are not subject to UWR regulations when disposed, regardless of the source. Some still fail the test, however, and are therefore covered by Federal Law when disposed by large-scale hazardous waste generators, such as manufacturing plants or hospitals.

Q: What do states say about disposing CFLs?

Practically all states have adopted the Federal UWR for lamps and thus apply the same requirements, including the aforementioned exemptions for households and most have adopted exemptions for small quantity generators. A small but growing number of states, however, now ban the disposal of all mercury-added lamps in solid waste, regardless of whether they fail the TCLP test and regardless of which party generates them. NEMA supports state recycling laws, where they exist.  

Q: Shouldn’t manufacturers recycle CFLs?

Manufacturers are in the business of product development, product manufacturing, and marketing. Recyclers constitute a completely different business sector and operate independently from the manufacturers, although the two groups have collaborated in various ways to promote lamp recycling.  Company representatives from the recycling industry are on record in several states vehemently opposing manufacturer involvement in recycling because they don’t wish to compete with CFL manufacturers.

Manufacturer-funded recycling systems would be inefficient and duplicative and serve only to increase the cost of energy efficient lighting to consumers.  Recycling options are increasing rapidly with limited manufacturer involvement and will continue to do so as markets evolve.  Meanwhile the newly enacted Energy Independence and Security Act, signed by President Bush in December 2007, directs US DOE to collaborate with the US EPA to review CFL disposal and recycling issues on a national level and submit a report to Congress within one year.

Q: Can CFLs be used in luminaires (lighting fixtures) with digital controls or dimming switches?

A limited number of CFLs are compatible with dimmers and control units, but most others still lack the circuitry required for those applications. Consumers should be careful to use only models marked as compatible with or suitable for control circuits and dimmers when choosing lamps for those luminaires. For a report by Underwriters Laboratories on the safety for (intentional) mis-combinations between CFL and Dimmers.

Q: Do CFLs emit Ultraviolet (UV) radiation or electromagnetic radiation (EMF) and are those harmful?

CFLs emit both, but at very (acceptably) low levels.  For more information please see Health Canada's recent report on CFLs in the home.


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