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Mercury in Our Environment

There are several forms of mercury that impact human health

Mercury in our environment is most commonly found in one of the following three main forms:

  • Elemental (metallic) mercury
  • Methylmercury 
  • Mercury salts

People mostly come in contact with mercury by eating fish and from spills of small amounts of metallic mercury, such as from a broken thermometer.

For more information on mercury, go to the Agency for Toxic Substances and Disease Registry (ATSDR) webpage on mercury.

Elemental mercury

Known as metallic mercury, this form of mercury is a heavy, silvery metal element that is a liquid at room temperature. These are mostly commonly found in the home in thermometers, barometers, electrical switches, and thermostats.

Liquid mercury evaporates at room temperature and these vapors are invisible, odorless, and, at high levels, are very toxic. Even small spills can cause high levels of mercury vapors that are unsafe to breathe. You should respond immediately to all mercury spills.


Known as organic mercury, this mercury is released from industries into the air and can travel long distances and end up in soil and in lakes. Our biggest concern for mercury’s impact on human health is when mercury builds up in fish. You should review fish health advisories to reduce your consumption of mercury.

Mercury salts

Mercury salts are used in fungicides and preservatives for seeds, wood products, fluorescent lights, and in the manufacture of batteries and paper. Mercury salts are quite corrosive and if eaten, can quickly damage tissues of the digestive tract and kidneys.

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Last revised April 13, 2023