“Mad as a hatter” In 18th and 19th century England, mercury was used in the production of felt, which was used in the manufacturing of hats common of the time. People who worked in these hat factories were exposed daily to trace amounts of the metal, which accumulated within their bodies over time, causing some workers to develop dementia caused by mercury poisoning. Thus the phrase “Mad as a Hatter” became popular as a way to refer to someone who was perceived as insane.
A Victorian Millinery Catalogue from 1896. Mad hatter disease, or mad hatter syndrome, is a commonly used name for hatmakers whose felting work involved prolonged exposure to mercury vapours. By the turn of the 20th century, mercury poisoning among British hatters had become quite rare.
MAD AS A HATTER 19th century Mercury used to be used in the making of hats. This was known to have affected the nervous systems of hatters, causing them to tremble and appear insane. Mercury poisoning is still known today as Mad Hatters disease.
Factory workers showed brain/ neurological disorders from handling mercury.