In 1969, Congress enacted the National Environmental Policy Act in response to public concern about the deteriorating quality of the "human" environment and the inadequate consideration of environmental impacts of major federal projects.

The human environment encompasses the following areas: physical (geology, soils, air, water), biological (plants, animals), social (communities, economics), and cultural (archaeological and historic resources).

The intent of the National Environmental Policy Act is to ensure safe, healthful, productive, and esthetically and culturally pleasing surroundings.