What is mercury?

Mercury is a naturally-occurring metal, which is widespread and persistent in the environment. It exists in three forms: elemental or metallic mercury, inorganic mercury, and organic mercury. Most of the mercury in the atmosphere is elemental mercury vapor, but most of the mercury found in water, soil, plants, and animals is either inorganic or organic (methylmercury). The majority of mercury found in fish is methylmercury, which tightly binds to protein in all fish tissue. Methylmercury is a particular concern because it can build up to levels in fish tissue that can be toxic to people.

Who is exposed to mercury?

Anyone may be exposed to mercury. Eating fish is the principal way that people are exposed to methylmercury. People may also be exposed to other forms of mercury from breathing contaminated workplace air or through skin contact, particularly in occupations involving chemical or dental work. Exposure may also occur by breathing vapors in air from spills, incinerators, and industries that burn mercury-containing fuels.

How can mercury affect my health?

The nature and extent of health effects from exposure to mercury will depend on the amount to which a person is exposed. Exposure to high levels of metallic, inorganic, or organic mercury can permanently damage the brain, kidneys, and developing fetus. Exposures to very high levels of mercury usually result from occupational exposure. Effects on brain functioning may result in irritability, shyness, tremors, changes in vision or hearing, and memory problems. People can also develop digestive problems and kidney damage. The U.S. Environmental Protection Agency (EPA) has determined that mercuric chloride and methylmercury are possible human carcinogens.

How can I reduce the risk of exposure to mercury?

Carefully handle and dispose of products that contain mercury, such as thermometers and compact fluorescent light bulbs. Because it can potentially vaporize, do not vacuum spilled mercury. If a large amount of mercury has been spilled or identified, contact your local health department. Do not purchase or use imported, homemade skin-lightening creams, and do not store them in your home.
Finally, be mindful of local fish consumption advisories in your area. The Virginia Department of Health (VDH) has established guidelines for issuing a fish consumption advisory when fish from certain waters are found to contain contaminants at levels of concern. For mercury, this level is 0.5 parts per million (ppm) of mercury in fish tissue. For information, visit

Compact fluorescent lights (CFLs) are safe to use in your home. No mercury is released when the bulbs are in use and they pose no danger to you or your family when used properly. CFLs do, however, contain approximately 4-5 milligrams (mg) of mercury (the amount equivalent to the tip of a pen), and thus should be managed responsibly when they burn out. Because of the small amount of mercury in the CFLs, if a CFL bulb breaks, following proper clean-up and disposal guidelines will minimize any risk from exposure. Guidelines can be found at EPA’s page on Cleaning Up a Broken CFL.


Updated 2021