Severe Enamel Fluorosis in Children

"Severe enamel fluorosis occurs at an appreciable frequency, approximately 10% on average, among children in U.S. communities with water fluoride concentrations at or near the current MCLG of 4 mg/L. Thus, the committee concludes that the MCLG of 4 mg/L is not protective against severe enamel fluorosis." from page 346

Fluoride in Drinking Water: A Scientific Review of EPA's Standards (2006)

In this report they are saying that 10% on average of kids in communities with close to 4 milligrams per liter in their drinking water have severe fluorosis!