Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.


Secure .gov websites use HTTPS
A lock () or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Also known as: Quicksilver, Liquid Silver
Chemical reference number (CAS): 7439-97-6

Do not vacuum spilled mercury - Follow proper cleaning guidance for mercury spills.

Mercury is a heavy, silvery-white metal element. It can exist as a liquid at room temperature or as a solid crystal salt. The liquid metal form gives off invisible, odorless, toxic vapors. Commonly, metallic mercury can be found in thermometers, barometers, electrical switches, thermostats and in dental fillings.

When mercury is released from industries into the air, it can travel long distances and be deposited on soil and in lakes. In lakes, small organisms change the mercury to a form of organic mercury (methylmercury) that builds up in the bodies of fish. Some lakes in Wisconsin have health advisories that recommend against eating too much of certain types of fish containing high levels of methylmercury.

Organic mercury is the most poisonous form. It is used as a fungicide and preservative for seeds, wood products, and paper products. In homes, organic mercury can be found in latex paints, and metallic mercury is sometimes used in religious rituals.

People can be exposed by breathing mercury vapors. This type of exposure can happen in the workplace or in homes where mercury is spilled.

People can be exposed to mercury by eating fish or shellfish caught in contaminated waters. Some dental fillings contain mercury and blood levels may be elevated for a short time after teeth are filled. Mercury can enter the body when contaminated water is used for drinking or for preparing food. If a water supply is contaminated, people can absorb mercury as they bathe or use the water for other purposes.

People who work with exterior latex-paints containing mercury can absorb mercury through their skin or by breathing in unsafe air in unventilated areas.

The Wisconsin Department of Natural Resources regulates the amount of mercury that can be released by industries.

No standards exist for the amount of mercury allowed in the air of homes. We use a formula to convert workplace limits to suggested home limits. Based on the formula, we recommend levels of mercury vapor be no higher than 2 ppb.

The state and federal drinking water standards are both set at 2 parts per billion (ppb) of mercury. We suggest you stop drinking water containing more than 2 ppb of mercury. If levels of mercury are very high in your water, you may need to avoid washing, bathing, or using the water for other purposes.

Everyone's Reaction is Different

A person's reaction to chemicals depends on several things, including individual health, heredity, previous exposure to chemicals including medicines, and personal habits such as smoking or drinking. It’s also important to consider the length of exposure to the chemical, the amount of chemical exposure, and whether the chemical was inhaled, touched, or eaten.

Breathing mercury's vapors is very dangerous. When metallic mercury is touched it can slowly pass through the skin.

The following health effects can happen immediately or shortly after exposure to high levels of mercury:

  • Neurological effects, confusion, hand tremors
  • Chills
  • Chest tightness, bronchitis, pneumonia
  • Abdominal pain, nausea, vomiting, and loss of appetite
  • Bleeding gums
  • Leg pains and burning sensation in feet
  • Lung and kidney damage
  • Skin rashes

Children and infants can develop a specific allergic reaction to mercury.

The following health effects can occur after several years of exposure to mercury (more than 10 ppb in air): People's nervous systems and kidneys are very sensitive to mercury and are easily damaged. Symptoms of damage include blood in urine, shaking, burning pain in legs and feet, sleep disturbance, personality changes, irritability and memory loss.

Blood, urine, hair and breast milk can all be tested for mercury. Normal levels of mercury in urine can vary, but are generally less than 15 micrograms per liter. Doctors can do additional medical tests to check kidney and nervous system functions.

Seek medical advice if you have any symptoms that you think may be related to chemical exposure.

Questions? Can't find what you're looking for? Email:

Last revised June 15, 2022