For the past seventy years, a host of scientific and public health bodies in the United States have strongly endorsed the practice of adding fluoride compounds to public water supplies as a prophylactic against dental caries. Throughout that period, a constant undercurrent of skepticism and outright opposition has slowed the adoption of the practice in the United States and limited its spread to just a handful of countries around the world. One of the attractions of water fluoridation is its affordability: the fluoride compounds are sourced from the phosphate and aluminum industries, for whom they would otherwise constitute an annoying toxic waste disposal problem. Despite this, proponents have nonetheless succeeded in shaping a narrative that casts fluoridation as "natural" or at least mimicking nature. I demonstrate how fluoridationists were able to persuasively argue that adding a pollutant to the water supply was safe and natural. In the process, I examine how environmental historians and historians of science approach topics such as fluoridation. I suggest that as a result of the influence of science and technology studies and an ontological turn toward hybridity, the two subdisciplines are becoming increasingly convergent.
Keywords: Environmentalism; moral authority of nature; pollution; public health; water fluoridation.