EXCLUSIVE — The Environmental Protection Agency has begun a multiyear study to determine the maximum safe level of fluoride in the nation’s drinking water, advancing a key objective of the “Make America Healthy Again” movement. 

Earlier this month, the EPA published a 75-page literature review and study design document outlining its plans to review the effects of fluoride on children’s brain development after a handful of studies showed a correlation between excessive fluoride intake and lowered IQ scores.