Ask Waste Watchers: Mercury and the Mad Hatter |

Ask Waste Watchers: Mercury and the Mad Hatter

Joseph Walls
Daily Correspondent
Vail, CO Colorado

Why is mercury poisoning called Mad Hatter syndrome?

Victoria in Vail

Thanks for the question, Victoria. It is a fascinating subject concerning an early occupational disease.

In England during the 1800s, hats were very fashionable. A person who made or sold hats was called a milliner or a hatter. Hats were usually made from beaver, rabbit or other animal skins. One of the steps involved in making a hat included treating the skins with a compound that contained mercury. Without proper ventilation or protective gloves, the hatters breathed mercury vapors and absorbed it through their skin.

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Exposure to these vapors over long periods of time led to mercury accumulation in the hatters’ bodies. The symptoms of long-term exposure were many and included trembling, loose teeth, slurred speech, memory loss, personality changes and insanity. The word “mad” in Mad Hatter syndrome actually refers to mental instability or insanity instead of anger. Even today, Mad Hatter syndrome is a term that appears in medical dictionaries (Stedman’s Concise Medical Dictionary for the Health Professions).

The original meaning of the phrase “mad as a hatter” is uncertain, but it became a popular expression in the 1800s to describe mental instability.

It is quite probable that the author Lewis Carroll knew something of the psychological effects associated with Mad Hatter syndrome, as well as the expression “mad as a hatter,” when he penned Alice’s Adventures in Wonderland in 1865. In the book, there is a character called the Hatter whom we are told is mad. Although there is no explicit reference to his being insane, who can forget the Hatter’s poem “Twinkle, twinkle, little bat! How I wonder what you’re at!”?

Over the years, we have become much more aware of the health hazards associated with mercury exposure than people were back in the 1800s. That being said, we still have quite a bit of mercury around us. Mercury can be found around the home in many shapes and forms, such as thermometers, thermostats, insect and weed killers made before 1988, medicines such as mercurochrome, certain button-cell batteries, interior and exterior paints older than 1991, wood preservatives and all fluorescent lighting.

This is why it is so important to avoid breaking devices or spilling products that contain mercury. When you are done with them, dispose of them properly. In Eagle County, you may safely dispose of all types of mercury-containing devices, fluorescent bulbs, batteries, paints and other chemicals at the Household Hazardous Waste facility at the landfill in Wolcott.

Household Hazardous Waste also accepts lots of other household items that should not be thrown in the garbage, such as aerosol cans, needles, all types of batteries, motor oil, antifreeze, corrosive materials, pool chemicals and flammable liquids.

Joseph Walls is hazardous-waste specialist at the Eagle County Household Hazardous Waste facility, located at the landfill in Wolcott. The facility is open 8 a.m. to 4 p.m. Monday through Friday and 8 a.m. to 3 p.m. on Saturday. Call 970-328-3468 or visit for information.

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