categories of environmental review for a proposed action exist. The decision to conduct one study
or another depends on the type of project and the potential consequences the project has to various
environmental categories. Criteria for determining which type of study should be undertaken are
defined in the environmental directives for each branch of service. Environmental studies should be
prepared and reviewed locally. When additional assistance or guidance appears necessary, this
support may be obtained through various agencies such as USAATCA, COE TSMCX (U.S. Army
Corps of Engineers Transportation Systems Center) and the U.S. Army Corps of Engineers District
Offices, Naval Facilities Engineering Command Headquarters and Engineering Field Divisions, and
the Air Force Center for Environmental Excellence (HQ AFCEE).
18.104.22.168. Environmental Assessment (EA). The EA serves to analyze and document the extent of
environmental consequences of a proposed construction project. It evaluates issues such as
existing and future noise, land use, water quality, air quality, cultural resources, fish and wildlife.
The conclusion of the assessment will result in either: (1) a Finding of No Significant Impact
(FONSI), or if the consequences are significant, (2) the decision to conduct an Environmental
Impact Statement (EIS). This decision is typically made by the authority approving the study.
22.214.171.124. Environmental Impact Statement (EIS). An EIS is the document which identifies the
type and extent of environmental consequences created if the proposed project is undertaken.
The EIS' primary purpose is to ensure that NEPA policies and goals are incorporated into the
actions of the Federal government. The EIS defines the impact, and details what measures will
be taken to minimize, offset, mitigate, or avoid any adverse effects on the existing environmental
condition. Upon completion of an EIS, the decision maker will file a Record Of Decision
(ROD), which finalizes the environmental investigation and establishes consent to either
abandon or complete the project within the scope of measures outlined in the EIS.
126.96.36.199. Categorical Exclusion (CX). A CX is used for projects that do not require an EA or EIS
because it has been determined that the projects do not have an individual or cumulative impact
on the environment, and present no environmentally controversial change to existing
environmental conditions. A list of actions which are categorically excluded is contained in the
regulatory directives for each service.
188.8.131.52. Exemption By Law and Emergencies. Situations where laws applicable to the DoD
prohibit, exempt, or make full compliance with NEPA impossible, or where immediate actions to
promote national defense and security do not allow for environmental planning, are exempt from
2.4.4. Aircraft Noise Studies. AICUZ and ICUZ are programs initiated to implement Federal laws
concerning land compatibility from the perspective of environmental noise impacts. The ICUZ
program is the Army's extension of the AICUZ which was initiated by DoD and undertaken
primarily by Air Force and Navy aviation facilities. Studies under these programs establish noise
abatement measures which help to eliminate or reduce the intensity of noise from its sources, and
provide land use management measures for areas nearby the noise source.
184.108.40.206. Analysis. Due to the widely varied aircraft, aircraft power plants, airfield traffic
volume, and airfield traffic patterns, aviation noise at installations depends upon both aircraft
types and operational procedures. Aircraft noise studies should be prepared for aviation
facilities to quantify noise levels and possible adverse environmental effects, ensure that noise
reduction procedures are investigated, and plan land for uses which are compatible with higher
levels of noise. While many areas of an aviation facility tolerate higher noise levels, many
aviation landside facilities and adjoining properties do not. Noise contours developed under the