Frequently Asked Questions:
Mercury in its liquid form

What is mercury?

Mercury is a naturally occurring element found in rocks, soil, water, air and living things. Mercury is the only metal that is liquid at room temperature. In its pure form (often called metallic or elemental), mercury is a shiny, silver-white, odorless liquid. If heated, mercury vaporizes into a toxic, colorless gas that is odorless to people.

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Why be concerned about mercury?

Mercury is a hazardous chemical. Mercury can damage the central nervous system, kidneys and liver. Both high level/short-term and low level/long-term exposures can lead to serious health problems.

High level, short-term exposure can cause skin rashes, diarrhea, and respiratory distress. Repeated exposure to low levels, or long-term, low-level exposure, can cause muscle tremors, irritability, personality changes, or rashes.

Nerve damage from mercury may start with a loss of sensitivity in hands and feet, difficulty in walking, or slurred speech. In rare cases it has caused paralysis and even death. The risk varies depending on how much mercury a person is exposed to, how long a person is exposed to mercury, and how often the person is exposed.

Fetuses and children are very sensitive to mercury. Pregnant women and women of child-bearing age should also avoid exposure to mercury.

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How might someone be exposed to mercury?

The greatest health danger from elemental mercury is through inhalation, or breathing in mercury vapor.

When elemental mercury is spilled or exposed to the air, it vaporizes slowly. In a warm environment (like a kitchen or on a hot plate) it will vaporize more quickly, resulting in higher indoor mercury levels. In its vapor form, mercury is easily inhaled and extremely toxic. If a person is exposed to mercury in air for a long enough time, even a small amount can affect his or her health.

If mercury is on the skin, there may be some irritation, and the best way to handle this is for the exposed person to shower with soap.

Mercury that is released outdoors will eventually vaporize into the air. Normally, the amount of mercury in outdoor air is extremely low, and this should not pose a health hazard.

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Steps to avoid mercury exposure

The best way to avoid a mercury spill is not to have any mercury in the house. Replace any mercury thermometers in your home with digital thermometers or alcohol (red bulb) thermometers. Replace old thermostats that contain mercury with non-mercury electronic thermostats. Most electronic thermostats can be programmed to automatically decrease fuel use and costs at night or when you are out of the house.

Thermometers, thermostats and other devices that contain mercury, such as barometers and spent fluorescent bulbs or tubes, should NOT be thrown in the trash. Instead, take them to your county’s household hazardous waste collection site. To find out where it is, go to the Minnesota Pollution Control Agency's Local household hazardous waste collection programs Web page or call 800-657-3843 or 651-296-6300, 8 a.m. to 4:30 p.m., Monday through Friday.

What should I do if mercury is spilled?

Spilled mercury, even small quantities in the home, should be cleaned up properly so that people don’t come in contact with it or breathe its vapors. Some ordinary cleanup measures, such as sweeping and vacuuming, are not appropriate when trying to clean up spilled mercury; as they will increase the health risks.

Mercury vapor is odorless, colorless and very toxic. Even though liquid mercury evaporates slowly, a significant amount of mercury vapor can build up indoors after mercury is spilled, and it can be dangerous to breathe these mercury vapors.

For advice about cleaning up a mercury spill in your home, contact the Minnesota Pollution Control Agency by calling the Minnesota Duty Officer at 800-422-0798 or 651-649-5451 anytime, day or night.

You should NOT attempt to clean up spilled mercury yourself unless the amount spilled is no more than what is contained in a fever thermometer and the spill did not occur in a warm environment, such as on a hot surface, or in a device that vaporizes liquids, such as a humidifier.

If it is appropriate for you to clean up the spilled mercury, follow the directions in the following fact sheet:

Cleaning Up Spilled Mercury in the Home (PDF: 286KB/5 page)

For more information about mercury, visit these sites:

Minnesota Pollution Control Agency: Mercury

U.S. Environmental Protection Agency: Mercury
(General information)

U.S. Environmental Protection Agency: Consumer and Commercial Products

U.S. Agency for Toxic Substances and Disease Registry: Mercury
(Health effects from mercury exposure)

For questions about exposure, please contact us.

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Updated Wednesday, 17-Jul-2013 11:46:19 CDT