Of all the possible exposures to mercury you may have in everyday life, the mercury found in thermometers and thermostats is among the easiest to avoid. Good alternatives to these products are widely available and government programs to replace them with safer products are well-established. This article will provide background information on the products and give you the information you need to eliminate these potential exposures in your home and workplace.
Thermometers
Most of us are familiar with mercury thermometers. They were used in almost every household when we were children. Mercury is the only metal that is liquid at room temperature and it expands and contracts evenly with temperature changes. It is also very stable over long periods of time. These properties make it desirable to use in thermometers. However, the combination of the necessity to shake down the mercury before use and the fragile glass tubes that are used often result in a broken thermometer and mercury exposure. The mercury in a thermometer is elemental mercury, the silvery liquid that most of us are familiar with. While marginally less toxic than the organic forms of mercury, elemental mercury will produce mercury vapor continuously unless it is cleaned up properly and thoroughly. The amount of mercury in a thermometer is significant; a typical infant/oral thermometer contains .61grams of mercury or 610,000 micrograms.
If you still have a mercury thermometer in your house, replace it now. It is an accident waiting to happen. Digital electronic, glass/alcohol and glass/gallium-indium-tin (Galinstan) thermometers are easy to find and affordable. The brand name for the Galinstan thermometers is Geratherm and while they appear to have a silvery metal inside, they will be labeled “mercury-free”. SafeMinds would recommend either a digital electronic thermometer with lithium batteries (no mercury) or the glass/alcohol variety which typically has red or blue liquid in it. Galinstan thermometers are considered non-toxic by the FDA and they are much safer than mercury thermometers if broken (soap and water clean-up) but there is limited toxicity data on gallium in human beings in the event of a thermometer breaking in someone’s mouth.
The threat posed by a mercury thermometer is not just theoretical. Von Muhlendahl (Lancet 1990) reported, “In yet another case, three children, ranging in age from 20 months to 6 years old, were exposed to mercury from a thermometer that had been spilled on a carpet. They developed symptoms including anorexia, weight loss, light sensitivity, pink, sweating, scaling palms, papulovesicular eczema with superinfections, severe prurigo and itching exanthema. The two more severely affected children required four months of therapy before complete recovery.”
As of October 2, 2008, thirteen states had laws that limit the manufacture, sale and/or distribution of mercury fever thermometers: California, Connecticut, Illinois, Indiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, New Hampshire, Rhode Island, Oregon, Washington. To put this in a global perspective, France, Sweden, Denmark and the Netherlands have all banned the use of mercury thermometers nationwide. In its 1997 report to congress, the EPA estimated that 16.8 tons of mercury from broken thermometers was disposed of as municipal solid waste in the year 2000. Given the ease of recycling, careful consumers could completely eliminate this source of environmental mercury.
Thermostats
Like thermometers, thermostats containing mercury are found in many older homes. Each one typically contains 3-5 grams of elemental mercury in a small glass ampoule. Unless the glass is broken, the mercury is not a health risk, but if the thermometer is crushed in a landfill, the mercury is released into our environment. The mercury in a thermometer acts to close the electrical circuit in the thermostat to turn your HVAC system on and off. Many manufacturers have discontinued making mercury thermostats as digital versions have become the standard. Consumers should also be aware that mercury containing thermostat probes can be found in gas-fired appliances with pilot lights like ranges, ovens, clothes dryers, water heaters, furnaces and space heaters.
In 1989, several large thermostat manufacturers joined together to form the Thermostat Recycling Corporation, a not-for-profit organization that facilitates the collection and recycling of used mercury thermostats. They currently have over 3000 locations in 48 states, primarily at HVAC wholesalers, that allow contractors to drop off old mercury thermostats. In 2008, TRC collected over 135,000 mercury-switch thermostats which was a 19% increase over 2007. Those collections diverted about 1300 pounds of mercury from municipal solid waste. Currently, 30 manufacturers that branded or distributed mercury-switch thermostats in the United States pay to fund this program.
To reinforce the importance of recycling, there are now 6 states with laws that require recycling of mercury-containing thermostats: Pennsylvania, California, Iowa, Maine, New Hampshire and Vermont. Pennsylvania and California just enacted their laws in 2009.
Take action
- Replace and recycle your old mercury thermometers. Most can be recycled at local hazardous waste collection days. Click here and then go to your state’s initial for a list of phone numbers for dates in your area.
- Call your electrician to replace your old thermostat with a programmable one. Recycle the old one. The new thermostat will save you money on heating and cooling costs. The old one can be recycled at HVAC wholesalers around the country: Go to http://www.thermostat-recycling.org and enter your zip code to find a nearby drop-off location. In the event that there is no convenient
