A federal court in California ruled late Tuesday against the Environmental Protection Agency, ordering officials to take action over concerns about potential health risks from currently recommended levels of fluoride in the American drinking water supply. The ruling by District Court Judge Edward Chen ... deals a blow to public health groups in the growing debate about whether the benefits of continuing to add fluoride to the water supply outweighs its risks. While Chen was careful to say that his ruling does not conclude with certainty that fluoridated water is injurious to public health," he said that evidence of its potential risk was now enough to warrant forcing the EPA to take action. "In all, there is substantial and scientifically credible evidence establishing that fluoride poses a risk to human health; it is associated with a reduction in the IQ of children and is hazardous at dosages that are far too close to fluoride levels in the drinking water of the United States," the judge wrote in his ruling. The judge's ruling cites a review by the National Institutes of Health's toxicology program finalized last month, which concluded that "higher levels" of fluoride is now linked to lowered IQ in children. Chen said he left it up to the EPA which of a number of options the agency could take in response to his ruling. They range from a warning label about fluoride's risks at current levels to taking steps towards tightening restrictions on its addition to drinking water.