Sources of elemental mercury (Hg0) include old natural gas regulators, manometers, sphygmomanometers, thermometers, and thermostats. Causes of Hg0 spills include improper storage, container breakage, children playing with Hg0, the breakage of devices containing Hg0, and ritualistic use of Hg0. Inhalation is the primary exposure route for Hg0. Mercury released into the environment can enter lakes and streams, where bacteria convert it into methylmercury, which bioaccumulates in fish. Chronic exposure to Hg0 vapors can damage the kidneys and neurologic system. Short-term exposure to high levels of Hg0 vapors may cause lung damage, nausea, vomiting, diarrhea, increases in blood pressure or heart rate, skin rashes, and eye irritation, among other effects. Minimizing Hg0 dispersal is important after an Hg0 spill. Tracking by shoes or apparel or vacuuming can spread Hg0, increasing airborne concentrations and cleanup costs. The Illinois Department of Public Health's response to an Hg0 spill depends on the size of the spill. Airborne concentrations after large spills are mapped with a mercury vapor analyzer (MVA). The cleanup begins with the spill site and any hot spots that were identified with the MVA. Hard surfaces can usually be cleaned, but contaminated porous items must be discarded. Leaving marginally contaminated items outdoors for a month or more during warm weather may dissipate the Hg0. After a cleanup, clearance sampling is conducted to determine if further cleanup is needed. The best way to prevent Hg0 spills is reduce its use. Key words: cleanup, elemental mercury, health effects, mercury, prevention, remediation, spill, spill management. Articles from EHP, especially the News section, may contain photographs or illustrations copyrighted by other commercial organizations or individuals that may not be used without obtaining prior approval from the holder of the copyright. Sources of elemental mercury (Hg 0 ) include old natural gas regulators, manometers, sphygmomanometers, thermometers, and thermostats. Causes of Hg 0 spills include improper storage, container breakage, children playing with Hg 0 , the breakage of devices containing Hg 0 , and ritualistic use of Hg 0 . Inhalation is the primary exposure route for Hg 0 . cleanup elemental mercury health effects mercury prevention remediation spill spill management pmc-status-qastatus 0 pmc-status-live yes pmc-status-embargo no pmc-status-released yes pmc-prop-open-access yes pmc-prop-olf no pmc-prop-manuscript no pmc-prop-legally-suppressed no pmc-prop-has-pdf yes pmc-prop-has-supplement no pmc-prop-pdf-only no pmc-prop-suppress-copyright no pmc-prop-is-real-version no pmc-prop-is-scanned-article no pmc-prop-preprint no pmc-prop-in-epmc yes pmc-license-ref CC0 Elemental mercury (Hg 0 ), the silvery liquid most people associate with thermometers, is a liquid metal at room Four factors contribute to this: a ) Hg 0 vapors are heavy and settle, making concentrations higher at floor level, where young children play; b ) the blood–brain barrier of children is less able to keep mercury out of the brain; c ) the respiration rate of children is higher than that of adults, so children inhale more Hg 0 at a given concentration than do adults; and d ) the nervous system of children is still developing ( ATSDR 1999 , 2002 , 2004 ). At room temperature, short-term (acute) health effects from Hg 0 are infrequent; however, heating Hg 0 increases its evaporation. This can cause very high airborne concentrations and severe acute health effects. In Michigan, four adults melted down tooth fillings to recover the silver. However, these fillings contained about 50% mercury. After 1 day, all four people developed difficulty breathing. Despite medical care, all four patients died within 11–24 days. The home where the fillings were melted down was so contaminated that it had to be destroyed ( Taueg et al. 1991 ). At room temperature, long-term (chronic) exposure may cause adverse health effects. Chronic exposure of 1 month or more to low levels of Hg 0 can cause nervous system and kidney damage. Neurologic symptoms of mercury poisoning include decreased nerve impulse conduction, decreased motor skills (e.g., finger tapping and hand–eye coordination), irritability, poor concentration, shyness, tremors (initially affecting the hands and sometimes spreading to other parts of the body), incoordination (e.g., difficulty walking), and short-term memory loss. The motor skill effects may be reversible, but short-term memory loss may be permanent. Other symptoms may include abdominal cramps, diarrhea, eye irritation, nausea, skin rashes, and weight loss. EPA action levels did an inadequate cleanup of a school using only a special vacuum equipped with a filter to contain Hg 0 . Further cleanup was required. After a large spill, IDPH recommends family members leave their home or apartment, particularly if young children or pregnant women are present, and will refer the family to an occupational physician familiar with mercury poisoning to monitor exposure. Several tests will show the amount of mercury in the body. If an acute exposure to Hg 0 has occurred, a blood analysis will show mercury levels if performed within 3 days after the exposure. In adults, the background concentration of mercury is normally < 1.5 μg/dL blood ( IDPH 2004b ). Illinois has had pilot programs to assist schools in getting rid of mercury, but not on a permanent or statewide basis. For other states, contact the state environmental protection agency or the U.S. EPA regional office. Preventing Hg 0 Spills The best way to prevent spills is to keep Hg 0 out of the home, school, or workplace. The U.S. EPA (1999) has recommended that Hg 0 no longer be used for blood pressure and other medical devices, barometers, manometers, thermometers, or thermostats. The agency advises that these devices be replaced with Hg 0 -free alternatives, which are just as accurate and similar in cost.