Categorical Exclusion (CATEX) - A federal action may be "categorically excluded" from a detailed environmental analysis if the federal action does not, "individually or cumulatively have a significant effect on the human environment" (40 CFR § 1508.4).
Environmental Assessment (EA) - A federal agency can determine that a CATEX does not apply to a proposed action. The federal agency may then prepare an EA. The EA determines whether or not a federal action has the potential to cause significant environmental effects. If the agency determines that the action will not have significant environmental impacts, the agency will issue a Finding of No Significant Impact (FONSI). A FONSI is a document that presents the reasons why the agency has concluded that there are no significant environmental impacts projected to occur upon implementation of the action. If the EA determines that the environmental impacts of a proposed Federal action will be significant, an Environmental Impact Statement is prepared.
Environmental Impact Statement (EIS) - Federal agencies prepare an EIS if a proposed major federal action is determined to significantly affect the quality of the human environment. The regulatory requirements for an EIS are more detailed and rigorous than the requirements for an EA.
- Disclosing relevant information early in the analytical process,
- Pointing out state statutory and regulatory requirements,
- Offering technical expertise and staff support,
- Identifying potential redundancies in the NEPA process and procedures, and
- Improving efficiency for more consistent implementation of NEPA decisions.