When Did We Find Out Mercury Was Dangerous?

mercury thermometers

Mercury Thermometers (Photo credit: Wikipedia)

When did they stop making thermometers with mercury in them?

What is quicksilver?

Should we get our mercury fillings removed?

Is it true you could poison someone by leaving mercury in their car?

What are the signs of mercury poisoning?

What do fluorescent lamps have to do with mercury?

When Did They Stop Making Thermometers with Mercury in Them?

At the end of February, 2011, the National Institute of Standards and Technology  (NIST) stopped calibrating mercury thermometers, a service they had provided for 110 years.

Mercury thermometers for home use are being phased out, on the recommendation of both the American Academy of Pediatrics and the Environmental Protection Agency.

This is both to reduce the hazard in the home, if the thermometers break, and to reduce the load on the environment from mercury getting into the air, water and soil.

Liquid mercury expands at a steady rate when heated.

It was this observation that led to the invention of the mercury thermometer in 1714, by Daniel Gabriel Fahrenheit.

There are three kinds of mercury.

Elemental (liquid) mercury, sometimes called quicksilver, is the kind you find in thermometers, barometers and button batteries.

Elemental mercury vaporizes easily at room temperature, is odorless and colorless and can be inhaled easily.

While touching or inhaling small amounts of the mercury, as from one thermometer, is not dangerous, prolonged exposure and inhaling large amounts of the vapor can be.

Workers in the 1700s and 1800s in England, for example, risked dementia from mercury poisoning because mercury was used in the production of felt hats.

Thus, the phrase, “mad as a hatter.”

Mercury vapor was found to be dangerous when a German chemist, Alfred Stock, traced the symptoms he and other scientists were having to mercury vapor in the laboratory.

He wrote about it in a 1926 paper, “The Dangerousness of Mercury Vapor,” and worked to remove mercury from his lab.

The second kind of mercury is inorganic or mercury salt.

Inorganic mercury compounds are often found in high school science labs.

It is the least toxic of the three forms.

The third kind, organic mercury, or methylmercury, is the kind often found in the environment.

It is toxic and accumulates in fish.

Is It True You Could Poison Someone By Leaving Mercury In Their Car?

It’s not strong enough.

A Russian lawyer claimed she was targeted for assassination with balls of mercury left in her car.

The previous owner of her car admitted he had broken a barometer filled with mercury in the car before he sold it.

She had never cleaned it out.

Police officials said laboratory analysis concluded it was not potent enough to cause harm.

What Are the Signs of Mercury Poisoning?

Common symptoms include:

  • Itching or burning
  • Shedding of skin
  • Swelling
  • Pink cheeks, fingers or toes
  • Memory impairment
  • Insomnia
  • Muscle weakness

Click here for the entire list of symptoms of mercury poisoning.

The most common treatment is to identify and remove the source of mercury exposure.

Mercury has a half-life of seven to ten days.

What Do Fluorescent Lamps Have to Do with Mercury?

Fluorescent light bulbs and button batteries contain mercury.

Fluorescent bulbs should be disposed of carefully.

If they break in your home they should be cleaned up with wet paper towels and disposed of in a sealed plastic bag while the room is aired out.

Do not vacuum unless that is the only way to pick up the remaining glass as vacuuming can cause the mercury to disburse in the air further.

A case of mercury poisoning was reported in 1987 of a 23-month-old toddler who played frequently in a shed where a box of 8-foot fluorescent bulbs had broken.

Symptoms included anorexia, irritability, profuse sweating, and peeling and redness of fingers and toes.

Hardware stores or the hazardous waste site at the dump in your area may dispose of fluorescent bulbs for you.

Click here for a list of participating stores for recycling, but call ahead to see if your store participates.

Should We Get Our Mercury Fillings Removed?

Dental amalgam, the silver that was used to fill your cavities, is almost half mercury.

Now, dentists typically use a tooth-colored resin to fill cavities, both because it looks better and because there is some concern about having mercury in your mouth.

In the 1970s, studies showed that a small amount of mercury vapor is constantly being released from dental amalgam.

Although scientists agree on the fact that mercury vapor is released into the mouth, they disagree on whether it is enough to cause damage to your health.

The Food and Drug Administration has concluded there is insufficient evidence to verify the suspicion that it is damaging.

NIH recommends against removing dental amalgams simply to reduce mercury exposure.

Sweden, Denmark and Norway have banned its use in dental fillings.

Risk factors may include:

  • Number of fillings
  • Gum chewing and teeth grinding

Did you ever play with mercury from a broken thermometer?

Have your grandchildren ever seen liquid mercury?

Do you know where to dispose of fluorescent bulbs?

To you and the continued safety of your grandchildren.


Carol Covin, Granny-Guru, Grandma to two awesome 7-year-olds

Author, “Who Gets to Name Grandma? The Wisdom of Mothers and Grandmothers



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