It is a metal and conducts electricity. Because of these properties, mercury has been used in many household, medical and industrial products. Less than a third of the mercury in the environment is naturally occurring. The majority is released through preventable human pollution. All forms of mercury are toxic to humans.
Exposure can damage the brain and nervous system.
The developing brain of a fetus or child is especially vulnerable. The fetus of a mother who eats contaminated fish can be exposed to methylmercury via the mother's blood, and a nursing infant can be exposed by ingestion of breast milk. All mercury containing thermometers have been removed from clinical areas. All glass thermometers have been removed for the laboratory except one that is required for calibration by the National Standards Board. Since January of 1999, the Family Place, Concord Hospital maternity ward, has been placing digital thermometers in the newborn care kits.