Because mercury can be a gas, liquid, or solid, and because its properties include high conductivity and liquidity at room temperature, there are a whole host of applications in which it is useful. This includes being used in some types of thermostats.

Unfortunately, those same great properties can also make mercury a problem in the environment.

When mercury reaches lakes and rivers, bacteria converts that mercury into methyl mercury, which fish absorb from the water and food they eat. When methyl mercury builds up in fish, it can then be transferred to the humans who eat the fish. That can lead to problems with the human central nervous system, kidneys, and liver.

There is no question that mercury thermostats are extremely effective; indeed, they have provided excellent performance and value, along with accurate temperature control, for decades. However, contractors need to remember that mercury t-stats can’t just be thrown away when they are replaced. They either need to be recycled (if the program is available in your state) or disposed of through your local city or county mercury waste disposal program.

One person who would like to see the hvac industry work a little harder to ensure proper mercury thermostat disposal is Paul Arthur, a retired hvac instructor and active contractor in Port Charlotte, FL.

He’s spent the last 40 years in the hvac industry and became interested in the mercury problem when he was asked to present a program for the hazardous waste inspector at the Department of Environmental Services for Charlotte County.

“I was probably like most mechanics in the field — I never really knew a lot about what happened in the environment with mercury. It’s something you just don’t think about. In doing research for this program, though, I realized that this is really a problem. It’s a pervasive problem, and it goes back many years,” says Arthur.

The Dangers of Mercury

Once he realized how prevalent the problem was, Arthur became dedicated to making others aware about the dangers of mercury. In his classes, he promotes mercury thermostat recycling through entities such as the Thermostat Recycling Corp. (TRC). (See related story on this page.)

Arthur is quick to point out that the entire thermostat must be recycled or disposed of. “It is important to understand that they do want the whole thermostat, not just the bulb. Some guys just want to clip off the bulb, and TRC won’t take it because they’re afraid of it getting broken in transport.

“If there’s a mercury spill and it goes into a carpet, for example, you have to get rid of the whole carpet.”

If the thermostat recycling program is not available, contractors can make it easier for employees by having a box at the shop where technicians can place old mercury thermostats. Then someone can take in the box when the city or county has its hazardous waste disposal day.

Mandating it as part of a technician’s routine — and making it as easy as possible to do — will help ensure compliance.

Arthur notes that many contractors are already careful where mercury is concerned. “It seems like the licensed contractors know what to do [with mercury thermostats]. Where we have the problem is with people who are unlicensed. They just don’t understand or they don’t care.”

Other Common Sources of Mercury

You’d be wrong if you think that mercury thermostats are the only entities contributing to the environmental problem. In fact, according to EPA, only 1.6% of all mercury in the waste stream is caused by thermostats. That’s nothing to sneeze at, but a far greater problem is batteries, which contribute 86% of the mercury to the waste stream. So don’t think the problem will be solved by replacing the mercury thermostat with an electronic one.

When technicians replace an older electronic thermostat with a newer one, or if they simply replace the batteries during a service call, they need to properly dispose of the old batteries as well.

Again, the contractor can make this easier by placing a box out where technicians can throw their dead batteries at the end of the day. Technicians should also have a box on their trucks for old mercury thermostats and batteries.

Another problem is the testing equipment that technicians routinely use on service calls. “The gauges we use also contain mercury,” says Arthur. “I have a couple of absolute gauges that must have a pound of that mercury in them. Most contractors are not as aware that there’s mercury in those gauges.

“When I’ve had classes, I’ll ask, ‘What do you guys do with your old gauges?’ The guys will say, ‘Oh, I give that to my kids to play with.’ I say, ‘Do you realize this stuff goes into your body?’”

Arthur would like to see manufacturers of all products containing mercury (thermostats, batteries, gauges, etc.) place a warning on the boxes that the product needs to be recycled or disposed of properly.

“The manufacturers may have a little blurb about mercury in fine print, but I think it needs to be large print on the outside of the box. We need to make people aware that it’s a real problem.”

Sidebar: TRC Continues to Collect Mecury

ROSSLYN, VA — Because it is illegal to throw away mercury-switch thermostats, contractors usually leave them with homeowners, who do not know what to do with them. It’s one of the reasons why the Thermostat Recycling Corporation (TRC), located here, formed its recycling program in January 1998.

The program allows contractors to drop off old mercury-switch thermostats — no matter what brand they are — at participating wholesalers, who then put them in protective bins supplied and picked up by TRC. In just three years, TRC said it has recovered 656 lbs of mercury from 75,000 used thermostats.

“This program makes the decision of what to do with used thermostats easy,” said Ric Erdheim, TRC executive director. “It is easy, free, and then neither contractors nor homeowners need to worry about how to dispose of the thermostat.”

The mercury-switch thermostat recycling program was originally available only to hvacr contractors in nine states — Florida, Illinois, Indiana, Iowa, Michigan, Minnesota, North Dakota, Ohio, and Wisconsin. However, TRC expanded its program in January 2000 to include the District of Columbia, Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont, Virginia, and West Virginia.

For a listing of wholesalers who participate in the program, visit ment/trcwholesaler.xls (website).

For more information about the program, contact Erdheim at 703-841-3249; ric_erdheim@ (e-mail).

Publication date: 03/26/2001