I knew a retired gent (white, English, a British soldier in World War 11) and he shared with me how young conscripts were manipulated and tricked into participating in experiments to see how long healthy males could withstand various nerve gasses.

While stationed in Palestine(beingturned into Israel) he was tasked with emptying bags of fluoride into the wells of Palestinian villages. he was told it was to their improve dental health!

Years later he learnt that fluoride in higher doses, has a pacifying/tranquilising effect. In higher doses, it is a poison and was used as rat poison in the early 20th century in the USA.