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, an appointee of former President Barack Obama, 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. //

"One thing the EPA cannot do, however, in the face of this Court's finding, is to ignore that risk," he wrote.

Michael Connett, a partner at the law firm Siri & Glimstad and the lead attorney for the groups who brought the lawsuit, said the law now requires EPA to take action to remove the risk of fluoride.

"From our vantage point, the obvious way of eliminating the risk from adding fluoride chemicals to drinking water is to stop adding them," he told CBS News.