Lee County commissioners voted unanimously on Tuesday 4 to become the 40th Florida county to stop adding fluoride to drinking water. Spearheaded by Commissioner Cecil Pendergrass, the move flies against the advice of the American Dental Association and the American Medical Assocation.

Dozens of Florida municipalities have decided to stop adding floride to its drinking water over concerns the practice may affect the cognitive ability of kids.

Fluoride is a mineral long proven to strengthen teeth and prevent cavities when added to water in small amounts. Local utilities across the country have been putting fluoride in water since 1945 to help fight tooth decay. The CDC considers the practice one of the great public health achievements of the 20th century.