Passed in 1970, the federal National Environmental Policy Act requires lead public agencies to prepare and submit for public review environmental impact reports and statements on major federal projects under their purview with potentially significant environmental effects.

According to the Department of Energy, administrator of NEPA:

” 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:

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

NEPA also influenced passage of the California Environmental Policy Act, commonly known as CEQA.

NEPA stresses an interdisciplinary approach to federal project planning based on an environmental impact assessment, the DOE says. As part of this, federal officials consider environmental values alongside the technical and economic factors.

The DOE adds of the NEPA process, “Environmental impact assessment also calls for the evaluation of reasonable alternatives to a proposed Federal action; solicitation of input from organizations and individuals that could potentially be affected; and the unbiased presentation of direct, indirect, and cumulative environmental impacts.”