 One such theory is that fluoridation was a public-relations ruse sponsored by fluoride polluters such as the aluminium maker Alcoa and the Manhattan Project, with conspirators that included industrialist Andrew Mellon and the Mellon Institute's researcher Gerald J. Cox, the Kettering Laboratory of the University of Cincinnati, the Federal Security Agency's administrator Oscar R. Ewing, and public-relations strategist Edward Bernays.Specific antifluoridation arguments change to match the spirit of the time.Outside North America, water fluoridation was adopted in some European countries, but in the late 1970s and early 1980s, Denmark and Sweden banned fluoridation when government panels found insufficient evidence of safety, and the Netherlands banned water fluoridation when "a group of medical practitioners presented evidence" that it caused negative effects in a percentage of the population.