Utah’s Republican Gov. Spencer Cox signed a law Friday to prohibit fluoride in public drinking water amid a recent surge of concern over the mineral additive—despite decades of backing by public health officials—fueled in part by Health Secretary Robert F. Kenney Jr.’s claims of its potential health risks.

Utah has become the first state to ban fluoride in public drinking water, despite widespread opposition from dentists and national health organizations.

Utah became the first U.S. state to ban fluoride in its public water systems under bill signed into law by Gov. Spencer Cox.