Public fluoridation was first proposed by Gerald Judy Cox, who worked for the big aluminum company Alcoa in the 30s.
Sodium fluoride is a highly toxic byproduct of aluminum production. It was the active ingredient in rat poison and pesticide. In the 30s, Alcoa was facing a lot of lawsuits around sodium fluoride pollution.
Disposing of their sodium fluoride as toxic waste as per EPA regulations would be a hassle. So they came up with a brilliant plan. They wouldn't pay to dispose of their waste. They would SELL their waste. And they'd sell it to the US government.
First, they got their own scientist, Gerald Cox, to run some quick experiments showing fluoride reduces cavities in mice. Then, they used this evidence to recommend that the public health services fluoridate the public water supply.
Luckily, Alcoa had their own guy, Andrew Mellon, a major investor in Alcoa, serving as Treasury Secretary. And at the time, the Treasury Secretary's jurisdiction included the department of Public Health Services.
The US gov also hired Sigmund Freud's nephew, Edward Bernays, author of 1928 book Propaganda, to transform the image of sodium fluoride from environmental toxin to oral health miracle. And so Alcoa managed to turn their toxic waste problem into profits.
Yes, we switched from sodium fluoride to fluorosilic acid in the 50s, but the story is still concerning.