National Environmental Policy Act (NEPA)

Congress enacted NEPA in December, 1969, and President Nixon signed it into law on January 1, 1970. NEPA was the first major environmental law in the United States and is often called the “Magna Carta” of environmental laws. Importantly, NEPA established this country’s national environmental policies.

To implement these policies, NEPA requires agencies to undertake an assessment of the environmental effects of their proposed actions prior to making decisions. Two major purposes of the environmental review process are better informed decisions and citizen involvement, both of which should lead to implementation of NEPA’s policies.

Once the proposal is conceptualized and any reasonable alternatives have been developed, the agency must determine if the action has the potential to affect the quality of the human environment. This process results in one of three levels of NEPA analysis. Agencies may:

a. apply a Categorical Exclusion;
b. prepare an Environmental Assessment (EA); or
c. prepare an Environmental Impact Statement (EIS).

Source:Council on Environmental Quality, Executive Office. 2007. Citizens Guide to NEPA. Accessed on 9 September 2013. Available at