For each plan/project, the planning process takes a course that includes NEPA environmental compliance documentation. This environmental documentation can take three forms, either a Categorical Exclusion (CE) document, an Environmental Assessment (EA) or an Environmental Impact Statement (EIS).

Categorical Exclusion (CE)
By definition, a categorical exclusion refers to a group of actions, typically within a single project, that does not individually or cumulatively have a significant impact on the human environment. These exclusions also, by law have been found to have no effect in the federal guidelines that the National Park Service follows. Because of this, neither an environmental assessment nor an environmental impact statement is required.

Categorical exclusions for 2002, 2003, 2004, 2005 are available electronically. You can find CEs since October 2005 here.

Environmental Assessments (EA)
These are public documents required under the National Environmental Policy Act (NEPA) that identifies and analyzes activities that might affect the human and natural environment. An environmental assessment is a concise public document which provides sufficient evidence and analysis for determining whether to prepare an Environmental Impact Statement (EIS), aids an agency’s compliance with NEPA when no EIS is necessary, and it facilitates preparation of an EIS when one is necessary.

Environmental Impact Statements (EIS)
A detailed statement required by the National Environmental Policy Act (NEPA) when an agency proposes a major action that significantly affects the quality of the human environment. This document describes and analyzes the activities that might affect the human environment.