A federal judge has ordered the U.S. Environmental Protection Agency to further regulate fluoride in drinking water because high levels could pose a risk to the intellectual development of children. U.S. District Judge Edward Chen cautioned that it’s not certain that the amount of fluoride typically added to water is causing lower IQ in kids, but he concluded that mounting research points to an unreasonable risk that it could be. He ordered the EPA to take steps to lower that risk, but didn’t say what those measures should be. It’s the first time a federal judge has made a determination about the neurodevelopmental risks to children of the recommended U.S. water fluoride level, said Ashley Malin, a University of Florida researcher who has studied the effect of higher fluoride levels in pregnant women.