(a) Programmatic environmental documents. Agencies may prepare programmatic environmental documents, which may be either environmental impact statements or environmental assessments, to evaluate the environmental effects of policies, programs, plans, or groups of related activities. When agencies prepare such documents, they should be relevant to the agency decisions and timed to coincide with meaningful points in agency planning and decision making. Agencies may use programmatic environmental documents to conduct a broad or holistic evaluation of effects or policy alternatives; evaluate widely applicable measures; or avoid duplicative analysis for individual actions by first considering relevant issues at a broad or programmatic level.

(1) When preparing programmatic environmental documents (including proposals by more than one agency), agencies may find it useful to evaluate the proposal(s) in one of the following ways:

(i) Geographically, including actions occurring in the same general location, such as body of water, region, or metropolitan area.

(ii) Thematically or by sector, including actions that have relevant similarities, such as common timing, effects, alternatives, methods of implementation, technology, media, or subject matter.

(iii) By stage of technological development, including Federal or federally assisted research, development, or demonstration programs for new technologies that, if applied, could significantly affect the quality of the human environment. Documents on such programs should be completed before the program has reached a stage of investment or commitment to implementation likely to determine subsequent development or limit the choice of reasonable alternatives.

(2) Agency actions that may be appropriate for programmatic environmental documents include:

(i) Programs, policies, or plans, including land use or resource management plans;

(ii) Regulations;

(iii) National or regional actions;

(iv) Actions that have multiple stages or phases, and are part of an overall plan or program; or

(v) A group of projects or related types of projects.

(3) Agencies should, as appropriate, employ scoping (§ 1502.4 of this subchapter), tiering (paragraph (b) of this section), and other methods listed in §§ 1500.4 and 1500.5 of this subchapter, to describe the relationship between the programmatic environmental document and related individual actions and to avoid duplication and delay. The programmatic environmental document shall identify any decisions or categories of decisions that the agency anticipates making in reliance on it.

(b) Tiering. Where an existing environmental impact statement, environmental assessment, or programmatic environmental document is relevant to a later proposed action, agencies may employ tiering. Tiering allows subsequent tiered environmental analysis to avoid duplication and focus on issues, effects, or alternatives not fully addressed in a programmatic environmental document, environmental impact statement, or environmental assessment prepared at an earlier phase or stage. Agencies generally should tier their environmental impact statements and environmental assessments when it would eliminate repetitive discussions of the same issues, focus on the actual issues ripe for decision, and exclude from consideration issues already decided.

(1) When an agency has prepared an environmental impact statement, environmental assessment or programmatic environmental document for a program or policy and then prepares a subsequent statement or assessment on an action included within the program or policy (such as a project- or site-specific action), the tiered document shall discuss the relationship between the tiered document and the previous review, and summarize and incorporate by reference the issues discussed in the broader document. The tiered document shall concentrate on the issues specific to the subsequent action, analyzing site-, phase-, or stage-specific conditions and reasonably foreseeable effects. The agency shall provide for public engagement opportunities consistent with the type of environmental document prepared and appropriate for the location, phase, or stage. The tiered document shall state where the earlier document is publicly available.

(2) Tiering is appropriate when the sequence from an environmental impact statement or environmental assessment is:

(i) From a programmatic, plan, or policy environmental impact statement or environmental assessment to a program, plan, or policy statement or assessment of lesser or narrower scope or to a site-specific statement or assessment.

(ii) From an environmental impact statement or environmental assessment on a specific action at an early stage (such as need and site selection) to a subsequent statement or assessment at a later stage (such as environmental mitigation). Tiering in such cases is appropriate when it helps the agency to focus on the issues that are ripe for decision and exclude from consideration issues already decided or not yet ripe.

(c) Reevaluation. When an agency prepares a programmatic environmental document for which judicial review was available, the agency may rely on the analysis included in the programmatic environmental document in a subsequent environmental document for related actions as follows:

(1) Within 5 years and without additional review of the analysis in the programmatic environmental document, unless there are substantial new circumstances or information about the significance of adverse effects that bear on the analysis; or

(2) After 5 years, so long as the agency reevaluates the analysis in the programmatic environmental document and any underlying assumption to ensure reliance on the analysis remains valid. The agency shall briefly document its reevaluation and explain why the analysis remains valid considering any new and substantial information or circumstances.