The Dangers of Mercury Fever Thermometers

Mercury fever thermometers, the small glass tube with the silvery-white liquid inside have already been banned in San Francisco, California and Duluth, Minnesota and other areas. "Mercury thermometers are the greatest source of mercury pollution in our municipal solid wastes," says Mark Leno, the San Francisco supervisor who sponsored the ordinance. "There's absolutely no reason to use mercury thermometers when nonpolluting thermometers are available that are just as effective and affordable."

A toxic substance that can harm both humans and wildlife, mercury has been blamed for illnesses ranging from mood swings and gum disease to paralysis, poisoning the nervous system, and even death. "Thousands of people break mercury thermometers every year, and few of them have problems as a result, but, in terms of exposure to mercury vapor, which can require health attention, in a small percentage of cases where the mercury is not cleaned up properly, that can be a problem," says Alexis Cain, an EPA environmental scientist in Chicago.

When a mercury vapor thermometer breaks, the mercury can evaporate, creating a risk of dangerous exposures to mercury vapor in indoor air. This is especially true if a consumer fails to clean up the mercury, or uses a vacuum cleaner, shop vac, or broom to clean the spill. These methods will vaporize the liquid more rapidly, increasing the health risk, especially if the room is small and poorly ventilated.

To properly clean up a thermometer that has broken on a smooth surface, use two stiff pieces of paper to scoop all of the beads into a sealable, plastic container. If it is necessary, you can use an eyedropper to capture the beads. Wipe the area with a damp sponge. Place all the cleanup materials, including the sponge, paper, eyedropper, and any contaminated portion of rug or carpet into marked plastic containers, and take them to a local mercury-recycling site.

While the risk associated with breaking an individual thermometer may seem small, the total amount of mercury released into the environment as the result of thermometer use is astounding. Fever thermometers containing an estimated 17 tons of mercury are discarded annually to municipal solid waste in the United States, making fever thermometers the single largest source of mercury to municipal solid waste.

When mercury enters the environment and is deposited in lakes and rivers, it is transformed into the highly toxic methylmercury. Methylmercury builds up in the food chain. A small amount of mercury deposited in a lake can lead to dangerous levels of methylmercury in fish. Any person who consumes large amounts of fish is at risk for suffering the adverse effects of methylmercury on the nervous system. Forty states have advisories for mercury in one or more water bodies, and eleven states have issued statewide mercury advisories.

The safer alternatives to mercury fever thermometers include digital electronic thermometers, glass alcohol thermometers, glass gallium-indium-tin (galinstan) thermometers, ear canal thermometers, and flexible "forehead thermometers". Although there are known environmental damages caused by these alternative thermometers, they are significantly less than their mercury counterparts.