Danbury’s deadly hat industry

From the New England Historical Society

The 19th-Century hat factories of Danbury, Conn., made physical wrecks of thousands of workers. They turned them into mad hatters with symptoms known as the Danbury shakes.

In a Danbury hat mill.

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Hat makers used mercuric nitrate to make hats. Many developed mercury poisoning, manifested as drooling, pathological shyness, irritability and tremor. Mercury poisoning looked a lot like drunkenness, a handy misconception for employers to exploit.

Here’s the whole article.