Everyone has some uranium in their urine, although the amount varies greatly depending on where they live, and the type of work they perform. The National Center for Environmental Health of the U.S. Centers for Disease Control and Prevention (CDC) published data in 2005 on the amount of uranium found in the urine of men, women, and children from throughout the United States in the Third National Report on Human Exposure to Environmental Chemicals. However, people who work in uranium mines or mills may have higher levels in their urine, reflecting greater amounts of uranium in their bodies. The Occupational Safety and Health Administration has established a maximum safe level for those workers that is about 100 times higher than the average level found in the study by the CDC.