Success of mercury bans in reducing exposure to mercury in Illinois

Background: Elemental mercury has been used in many household medical and electrical devices. If spilled, mercury easily volatilizes and can be inhaled by occupants. Elemental mercury is well absorbed by inhalation and can result in respiratory or nervous system disease. Children are especially sensitive to the effects of mercury.  The objectives of this study were to estimate the prevalence of elemental mercury exposure in Illinois both prior to and after the ban of mercury thermometers in Illinois in July 2004 and to describe the epidemiologic characteristics of these cases.

Methods: The National Poison Data System was searched for exposure calls regarding elemental mercury from January/2000-March/2013. Only calls with elemental mercury as a single agent were included. Cases were excluded when it was deemed that the reported effects were unrelated to mercury or if the exposure was intentional.

Results: The number of mercury thermometer exposures in Illinois was significantly reduced after the ban, but there was minimal effect on exposures to other sources of elemental mercury. About 1% of thermometer cases and about 10% of cases involving other sources of elemental mercury were judged to be potentially toxic or documented to result in clinical effects.  The majority of thermometer exposures occurred in females and children, and the majority of these were via ingestion. Exposures occurred most frequently in a residence or in schools. January and February were the most frequent months involved, likely reflecting increased thermometer use during cold and flu season.

 Conclusions: The mercury thermometer ban was very successful in reducing exposure to mercury from thermometers, however other sources of elemental mercury remain a problem in Illinois. Further work should be done to continue to raise awareness of caregivers about the risk of mercury and to provide opportunity to remove mercury from homes.