Metallic elemental mercury, that slippery, shiny, silver-white liquid found in old-style thermometers, blood pressure devices, and other products, fascinates the inquisitive, who usually are unaware of mercury's less "flashy" side. That's what happened in Nevada in January 2004, when a student, who brought a large amount of liquid mercury to his middle school in a rural part of the state, spilled the mercury on the school bus and in the school. Health effects of mercury can depend on the form of mercury to which people are exposed as well as on the severity and length of exposure. For example, acute exposure to large amounts of elemental mercury vapor can severely damage a person's lungs.
Nevada health officials asked CDC epidemiologists and laboratory scientists to help assess mercury exposure of children and staff at the school. CDC staff administered questionnaires and obtained urine samples from 200 students and 80 staff who responded to announcements offering free testing after the mercury spill. Test results suggested that transient exposures to mercury, such as may occur when children find and play with mercury in its elemental form, are associated with negligible absorption. They found that only one child—the boy who brought the mercury to school—had a mercury level that was slightly above levels found in the general U.S. population. Information about U.S. population levels of many chemicals, including mercury, is published in CDC's National Report on Human Exposure to Environmental Chemicals. Health officials compared test results with mercury-exposure information from the Report to determine that no one else needed testing for mercury exposure, and no one required treatment.
