National Environmental Policy Act

The National Environmental Policy Act (NEPA), “pronounced nee-pa”, was passed in 1969 to encourage “harmony between man and his environment.” It effectively requires federal agencies to consider the impacts of their decision-making and planning on the environment. The “NEPA process,” as it has come to be known, provides a framework for the agencies to investigate the environmental impacts of their proposed actions and reasonable alternatives to those actions. To meet this requirement, federal agencies prepare a detailed statement known as an Environmental Impact Statement (EIS) for each of the projects they manage.

National Environmental Policy Act 
http://ceq.eh.doe.gov/nepa/nepanet.htm