Department of Natural Resources reminds Missourians about mercury hazards

The Missouri Department of Natural Resources is reminding Missourians that mercury still poses contamination hazards from improper handling and potential health risks from exposure. People should know what mercury is and the risks of unsafely handling the toxic material. They should also understand how to prevent spills, how to safely dispose of mercury-containing devices and what actions to take if a spill occurs.

The department was involved in at least nine mercury spills in 2023, underscoring the importance of mercury awareness and safety. Reported incidents occurred across the state and included mercury that had been poured down a college campus sink and releases from a damaged computer inside a business and a broken blood pressure cuff at a health care facility.

The year’s most serious release, however, occurred when U.S. Postal Service facilities in two cities were contaminated and a postal service employee was potentially exposed to mercury that had leaked out of a mailed package. The employee was sent to a hospital as a precaution to be monitored for mercury exposure and the two facilities required extensive environmental investigation and remediation.

“Some people may think mercury poisoning is a thing of the past, but that’s just not true,” said Lynn Milberg, director of the department’s Environmental Services Program. “Folks need to realize that mercury is still around, it must be handled very carefully and exposure can cause serious health impacts.”

Health Risks

Elemental or metallic mercury, the silver fluid that many have seen in science class, is liquid at room temperature and has no odor. When mercury is spilled, some of it will evaporate into the air and the vapor can move long distances. Mercury is toxic when inhaled or absorbed through the skin. Improper cleanup easily spreads the mercury and increases exposure risk by dispersing it into the air or onto furniture, carpets, clothes and other surfaces.

Everyone’s health can be impacted by mercury exposure. However, unborn babies and young children are at greatest risk because of their developing central nervous systems. If mercury exposure is suspected, contact a healthcare provider immediately.

Short-term exposure to high levels of mercury vapors may cause serious health effects, including nausea, vomiting, diarrhea and lung damage. It can also cause increased blood pressure, heart rate, skin rashes and eye irritation.

Symptoms from long-term mercury exposure can develop in just a few weeks and include tremors, decreased hand-eye coordination, memory problems, insomnia and irritability. If these symptoms are not correctly identified and further exposure prevented, permanent nervous system damage can occur. The Missouri Department of Health and Senior Services offers more information about mercury health risks on its website.

Spill Prevention and Safe Disposal

Mercury is still used in many devices such as thermometers, barometers, switches, thermostats and fluorescent lamps. Bulk elemental mercury and laboratory reagents are also used in school science labs. Improperly storing or mishandling mercury-containing items can cause dangerous and costly mercury spills, so people should be aware of what items contain mercury and know how to safely handle them to prevent accidents that could release the mercury. People can most easily prevent spills by discontinuing the use of these items and switching to safer alternatives.

Most items that contain mercury can be replaced with mercury-free (or lower-mercury) alternatives. These include spirit-filled or digital thermometers, electronic thermostats and switches, manual blood pressure monitors and other digital devices.

The department encourages citizens not to discard mercury-containing items in their trash, but to use household hazardous waste facilities as their first option for proper disposal. A list of permanent household hazardous waste facilities in Missouri is available online.

According to state and federal regulations, businesses and schools are required to manage mercury-containing waste items, such as laboratory chemicals and jars of elemental mercury, as hazardous waste. Anyone who regularly handles these items should know the regulations for safely disposing of any items that contain mercury.

Heating and air conditioning contractors can participate in a collection program through the Thermostat Recycling Corporation, a non-profit corporation that facilitates the collection and proper disposal of all wall-mounted mercury-switch thermostats. To find local collection sites and for more information, visit nema.org/gov/ehs/trc.

Spill Cleanup and Safety

Only a small amount of mercury is contained in common thermometers, so a broken device does not present an immediate health risk. However, if not quickly and properly cleaned up, the released mercury can present a long-term exposure risk.

Mercury spills should only be addressed by properly trained and equipped professionals. Incorrectly handling a spill can create a worse problem, making cleanup much more expensive and increase the time needed for full remediation. Cleaning up a mercury spill typically requires the contaminated property to be vacated until it is deemed safe. After a spill, small mercury beads can form and scatter making them difficult to find and clean thoroughly. Any remaining mercury beads will gradually form mercury vapors that can lead to inhalation and long-term exposures and health risks.

If a spill occurs, keep everyone away from that area and do not try to clean it up. Immediately remove any potentially contaminated clothes and place them in the same spill location. Leave the home or building and call the department’s Environmental Emergency Response 24-hour hotline at 573-634-2436 for guidance.

More mercury information resources are available at dnr.mo.gov/monitoring/mercury.