News Release 691

Department of Natural Resources responds to mercury release at Ozark County school

Volume 38-691 (For Immediate Release)
For more information: 573-751-1010 

JEFFERSON CITY, MO, DEC. 13, 2010 – The Missouri Department of Natural Resources responded this weekend to an Ozark County school to clean up a release of mercury from a broken thermometer.

Officials with Dora High School, Highway 181 South, notified the department Friday afternoon about 3:30 p.m. that a broken mercury thermometer had been found in a classroom. Officials conducted an initial cleanup, closed and locked the room, and evacuated the students.

The department dispatched an emergency responder from its regional office in Springfield to clean up the mercury and monitor the room for mercury vapor. Inspection of the school revealed one location on the floor near the spill site with elevated levels of mercury vapor.

The responder cleaned the affected area Friday evening, and the room was placed on several cycles of heating and ventilation to reduce the presence of mercury vapors. Vapor monitoring done Sunday afternoon showed the area to be vapor free.  

According to the Department of Health and Senior Services’ Bureau of Environmental Epidemiology, any possible health issues for students will depend on their length and level of exposure to mercury vapors. In this case, the actions taken by the school likely minimized any mercury exposure.

People who are concerned about potential exposures may contact the Bureau of Environmental Epidemiology at 573-751-6102 for more information on mercury exposure or their personal physician for medical concerns.  

Metallic mercury is liquid at room temperature and has no odor. It was once commonly used in thermometers, barometers, switches and blood-pressure measuring devices.

When spilled, some of the metal will evaporate into the air and can be carried long distances. Mercury is toxic when inhaled. Improper clean up with a vacuum, paintbrush or household cleaner increases exposure by dispersing the mercury into the air. For more information on cleaning up mercury spills, see the department’s Website:

To report an environmental emergency, including mercury spills, please the contact the Department of Natural Resources’ spill line at 573-634-2436. For more information about the Missouri Department of Natural Resources contact the department at 800-361-4827 or 573-751-3443, or visit the department's Web page at