Research conducted under the direction of the EPA's Office of Research and Development (ORD) at the National Health and Environmental Effects Research Laboratory (NHEERL) provides the basis for the formulation of environmental policies and programs that span the breadth of enviromnmental research in the world today. NHEERL provides scientific research on the effects of contaminants and environmental stressors on human health and ecosystem integrity. Its research helps the Agency indentify and understand the processes that cause pollution and helps the Agency evaluate risks that pollution poses to humans and ecosystems.