National Environmental Policy Act (NEPA)
A federal law enacted in 1969 requiring review for any “major Federal action significantly affecting the quality of the human environment…” (link to NEPA Statute). Environmental review under NEPA can be triggered by major policy changes, public or private projects funded by, and private projects permitted by a federal agency. NEPA also created the Council on Environmental Quality (CEQ), which creates minimum standards for NEPA documentation and also serves as a clearinghouse for NEPA documentation.
Basic requirements for NEPA are outlined in the Code of Federal Regulations (40 CFR 1500). Types of NEPA documentation include an Environmental Assessment (EA), which often paired with a Finding of No Significant Impact (FONSI), and an Environmental Impact Statement (EIS). Standards and thresholds for what constitutes a “major federal action”, and what type of NEPA documentation is appropriate for each type of action, are determined by implementing regulations developed by each federal agency or Department.