32 CFR 651.20 - Environmental assessment.
An EA is intended to assist agency planning and decision-making. While required to assess environmental impacts and evaluate their significance, it is routinely used as a planning document to evaluate environmental impacts, develop alternatives and mitigation measures, and allow for agency and public participation. It:
(a) Briefly provides the decision maker with sufficient evidence and analysis for determining whether a FNSI or an EIS should be prepared.
(b) Assures compliance with NEPA, if an EIS is not required and a CX is inappropriate.
(c) Facilitates preparation of an EIS, if required.
(d) Includes brief discussions of the need for the proposed action, alternatives to the proposed action (NEPA, section 102(2)(e)), environmental impacts, and a listing of persons and agencies consulted (see subpart E of this part for requirements).
(e) The EA provides the proponent, the public, and the decision maker with sufficient evidence and analysis for determining whether environmental impacts of a proposed action are potentially significant. An EA is substantially less rigorous and costly than an EIS, but requires sufficient detail to identify and ascertain the significance of expected impacts associated with the proposed action and its alternatives. The EA can often provide the required “hard look” at the potential environmental effects of an action, program, or policy within 1 to 25 pages, depending upon the nature of the action and project-specific conditions.