Florida’s Surgeon General on Friday recommended against putting fluoride in the water, guidance that comes amid speculation he is being eyed for a position in President Donald Trump’s administration.

One of the most common elements on Earth, fluoride is naturally present in human bodies and water, and common in toothpaste and mouthwash. And for decades, the mineral has been added to the water supplies of thousands of communities across the United States to help prevent dental cavities and decay.