What are the different types of household lamps?

Incandescent lamps: The most common type of household light bulb.  An electric current passes through a thin filament, heating it and causing it to emit light.

Halogen lamps: A modified form of incandescent lamp. They are more expensive to buy but last twice as long.

Light Emitting Diodes (LEDs): Potentially the lighting type of the future. LEDs have an extremely long lifespan. It is expected that technological advances will reduce costs such that this lighting type can be introduced into homes in the near future.

Fluorescent lamps: A lamp filled with neon or argon gas, a little bit of mercury and coated with a fluorescent or phosphorescent powder. Fluorescent lamps come in many shapes and sizes.  Increasingly popular is the compact fluorescent light bulb (CFL) which is a type of lamp that fits into a regular light bulb socket.

What are the benefits of using CFLs?
A lot of families are switching to CFLs in their homes due to their longer life and to reduce their energy usage, which in turn reduces greenhouse gas emissions.

How does a CFL work?
CFLs are electrical discharge lamps that contain low-pressure mercury vapor and an inert gas, usually argon, making invisible ultraviolet (UV) light. The inside of the glass is coated with a fluorescent made with phosphor powder. The UV light causes the phosphor coating to fluoresce and emit visible light.

What is the concern from using CFLs?

CFLs contain mercury, a metallic element, and when broken, this mercury escapes.  Mercury makes CFLs operate more efficiently than an incandescent and halogen lamp.  Mercury exists in one of three forms: elemental mercury (metallic), inorganic mercury and organic mercury (e.g. methyl mercury). Elemental mercury is the main type of mercury used in CFLs.  Elemental mercury is a silvery liquid that can vaporize at room temperature due to its low vapor pressure and is the kind of mercury found in the old thermometers.^2,3  Exposure to mercury can be associated with health effects, but it depends on the form of mercury, the route of exposure and the duration of the exposure.

What is the amount of mercury contained in a CFL?

A CFL contains around 5 milligrams (mg) of mercury which is a lot less than in a mercury thermometer (5 mg vs 500 mg).  1000 mg is about the amount of sugar in a typical sugar packet.

How can I be exposed to mercury?

However, people may be exposed to the mercury contained in a CFL only if it is broken; mercury is not released from normal CFL use.  Breaking the CFL results in mercury vapor being released into the air and possibly inorganic mercury adsorbed to phosphor powder separating from the glass.  The primary form of mercury will be elemental mercury in air.  Over time, the inorganic mercury adsorbed to the phosphor powder will vaporize also.

The primary human exposure pathway will be inhalation of the elemental mercury.  There is an initial spike in air-borne mercury concentration following breakage of a CFL or linear fluorescent tube as mercury is released^3,4,5  followed by slower release of elemental or inorganic mercury present in solid and liquid forms.

There is some limited potential for dermal exposure to the powder if a person were to touch the powder directly.  It is possible that children could crawl on the floor where a CFL has broken and remaining powder might be absorbed by the skin.  Given the broken CFL involves glass, it is not likely that children would be allowed in the area of the broken CFL until after clean up.

How Do I Safely Clean-up a Broken CFL?

Here are the 5 simple steps to safely clean-up a broken CFL.

1.  Have people and pets leave the room, turn off heating/ac system, and then air out room by opening a window or door to the outside environment for 5-10 minutes before you start the clean-up.  The initial spike of mercury that has vaporized into the air will quickly get reduced to a small level that is safe for human exposure.
2. Use rubber or latex gloves while cleaning up.  Remove all broken glass and visible powder with either stiff paper or sticky tape.  Use a damp paper towel to help pick-up loose powder and small pieces.  If on carpet, you may vacuum area after large pieces are removed.  Once vacuuming is complete, vacuum cleaner bag should be removed and discarded (or empty and wipe the canister), along with other materials.
3. Place all materials in a sealable container (i.e. empty peanut butter jar), if not container is available, carefully place in a sealable bag.
4. Place sealed container/bag in an outside container until you can take it to a recycling center (i.e. Lowes) or dispose of according to your local government disposal requirements, if none available, it may be disposed of in your household trash.
5. Ventilate room and leave heating/ac system shut off for a couple more hours.

Authors:

Patricia Nance, M. Ed, M.A., Toxicology Excellence for Risk Assessment (TERA),nance@tera.org

Natalia Foronda, PhD, New Zealand Ministry of Health,Natalia_Foronda@moh.govt.nz

References

1. Nance, P; Patterson, J; Willis, A; Foronda, N; Dourson, M. (2012) Human Health Risks from Mercury Exposure from Broken Compact Fluorescent Lamps. Reg. Tox. Pharm. Volume 62, Issue 3 , April 2012, Pages 542–552.
2. WHO (World Health Organisation). (2003) Elemental Mercury and Inorganic Mercury Compounds; Human Health Aspects.  Concise International Chemical Assessment Document (CICAD) 50.World Health Organisation, Geneva. (www.who.int/ipcs/publications/cicad/en/cicad50.pdf)
3. U.S. EPA.  Toxicity and Exposure Assessment for Children’s Health (TEACH).  Summary Sheets on Elemental Mercury (http://www.epa.gov/teach/chem_summ/mercury_elem_summary.pdf) and Inorganic Mercury (www.epa.gov/teach/chem_summ/mercury_inorg_summary.pdf)
4. Aucott, M., McLinden, M., Winka, M. (2003) Release of mercury from broken fluorescent bulbs. Journal of the Air and Waste Management Association 53(2):143-151.
5. Johnson, N.C., Manchester, S., Sarin, L., Gao, Y., Kulaots, I., Hurt, R.H. (2008) Mercury release from broken compact fluorescent lamps and in situ capture by new nanomaterial sorbents. Environmental Science and Technology. 42: 5772-5778.
6. Stahler, D., Ladner, S., Jackson, H. (2008) Maine Compact Fluorescent Lamp Study.  Maine Department of Environmental Protection. Available at:http://maine.gov/dep/rwm/homeowner/cflreport.htm
7. Risher, J.F., De Rosa, C.T. (2007) Inorganic: The Other Mercury. Journal of Environmental Health. 70(4): 9-1