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Mercury is a naturally occurring element that is a silver-colored liquid at room temperature. It is sometimes referred to as a "heavy metal". Historically, mercury has been valued for its ability to:

  • Conduct electricity;
  • Measure pressure and temperature;
  • Form alloys with almost all other metals.

Because of these diverse properties, mercury has been used in a large number of household, commercial, medical and industrial applications, including:

  • Medical instruments and equipment, such as blood pressure, gauges, thermometers and x-ray machines;
  • Fluorescent lights;
  • Electrical switches and relays used in certain devices and equipment, such as lighting, thermostats, pumps, space heaters and computers;
  • Dental amalgam.

While mercury use in the United States has declined, the U. S. Environmental Protection Agency estimates that manufacturers use 500 - 600 metric tons of mercury annually as part of their production processes or to create products that rely on mercury's chemical and physical properties.