The U.S. Environmental Protection Agency (EPA or sometimes USEPA) is an agency of the federal government of the United States charged with protecting human health and with safeguarding the natural environment: air, water, and land. The EPA was proposed by President Nixon and began operation on December 2, 1970, when it was passed by Congress, and signed into law by President Nixon, and has since been chiefly responsible for the environmental policy of the United States. It is led by its Administrator, who is appointed by the President of the United States. The EPA is not a Cabinet agency, but the Administrator is normally given cabinet rank. The agency has approximately 18,000 full-time employees.