Eight of 10 major dog food brands tested contain fluoride in amounts up to 2.5 times higher than the Environmental Protection Agency’s (EPA) national drinking water standard. All dog foods were tested by an independent laboratory commissioned by Environmental Working Group (EWG). In all eight cases, the likely sources of excess fluoride were ingredients called “bone meal” and “animal byproducts.” EWG notes that “a 10-pound puppy that eats about a cup of dog food a day would consume 0.25 milligrams of fluoride per kilogram of body weight per day, an amount five times higher than the ”safe” level set by the Agency for Toxic Substances and Disease Registry (ATSDR) of the U.S. Department of Health and Human Services.” If you are concerned, EWG recommends switching to brands free of bone meal and animal byproducts.