The Federal Agency whose mission is to protect human health and to safeguard the natural environment &151; air, water, and land &151; upon which life depends. EPA provides leadership in the nation's environmental science, research, education and assessment efforts. EPA works closely with other federal agencies, state and local governments, and Indian tribes to develop and enforce regulations under existing environmental laws. EPA is responsible for researching and setting national standards for a variety of environmental programmes and delegates to states and tribes responsibility for issuing permits, and monitoring and enforcing compliance.