The National Environmental Policy Act (or, NEPA) was signed into law on January 1, 1970 by US President Richard Nixon.
The preamble reads:
"To declare a national policy which will encourage productive and enjoyable harmony between man and his environment; to promote efforts which will prevent or eliminate damage to the environment and biosphere and stimulate the health and welfare of man; to enrich the understanding of the ecological systems and natural resources important to the Nation..."
The action forcing provision of the law required an environmental impact statement (EIS) to be written for all major federal actions. A major federal action was later defined as something that a federal agency could prohibit or regulate. In practice, a project is required to meet NEPA guidelines when a federal agency provides any portion of the financing for the project. Sometimes, however, review of a project by a federal employee can be viewed as a federal action and would then, therefore, require NEPA-compliant analyses be performed.
An EIS is a document written to aid in decision making. It explores alternatives to a proposed action, and the environmental consequences of those actions. NEPA sought to put environmental concerns on par with economic motivations and technological feasibility when making a decision that could effect the environment. Hydrological/geological, biological/ecological and social are among the consequences considered.
NEPA requires that an EIS must include: the environmental impacts of the proposed action; unavoidable adverse environmental impacts; alternatives including no action; the relationship between short term uses of the environment and maintenance of long-term ecological productivity; irreversible and irretrievable commitments of resources; and secondary/cumulative effects of implementing the proposed action.
NEPA established the Council on Environmental Quality (CEQ) to write regulations for EISs and advise the executive branch on environmental issues.
- U.S. Department of Energy Office of NEPA Policy and Compliance (http://tis.eh.doe.gov/nepa/), National Environmental Policy Act Program.