U.S. Department of Defense - Missile Defense Agency

U.S. Department of Defense - Missile Defense Agency

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National Environmental Policy Act (NEPA)


The NEPA requires all federal agencies to evaluate and consider the environmental impacts of their proposed actions and reasonable alternatives to those actions. The NEPA process enables federal agencies such as the Missile Defense Agency (MDA) to make informed decisions about the consequences of our projects, to both solicit public input and inform the public about our findings, and to take actions that will protect the environment.

The NEPA process starts after a proposal is formulated to take a major federal action. In the process, there are three levels of analysis depending on whether or not a proposed action could significantly affect the environment. The basic levels of NEPA environmental review and documentation process include:

Categorical Exclusion (CATEX): A category of actions that normally do not have a significant effect on the human environment, and therefore do not require preparation of an environmental assessment or environmental impact statement. Some CATEXs are documented with a Record of Environmental Consideration (REC).

Environmental Assessment (EA): A document that determines whether or not a proposed action has the potential to cause significant environmental impacts. An EA briefly describes the proposed action and its need, any alternative actions to the proposed action, and the environmental impacts of the proposed action and alternatives. In the event an EA is prepared and there are no significant impacts identified that can’t be mitigated, then this determination and required mitigations would be documented in a Finding of No Significant Impact (FONSI). If there would be significant impacts that could not be mitigated, then an Environmental Impact Statement would be prepared.

Environmental Impact Statement (EIS): A detailed document prepared for proposed actions expected to have a significant impact on the quality of the human environment. An EIS describes the proposed action and its need, any alternative actions to the proposed action, and the environmental impacts of the proposed action and alternatives. The EIS process begins with publication of a Notice of Intent (NOI) and ends with the issuance of a Record of Decision (ROD). The ROD documents the decision on which action to implement and discusses mitigation and monitoring measures, if necessary.

Mitigation measures avoid or reduce the impact of the action and can include:

- Avoiding the impact by not taking action or not implementing certain parts of the action,

- Minimizing impacts by limiting the degree or magnitude of the action,

- Repairing, rehabilitating, or restoring the affected environment,

- Reducing or eliminating the impact by preservation and maintenance operations during implementation over time, and

- Compensating for the impact by replacing or providing for substitute resources or environments.

NEPA Process

How the MDA implements NEPA


Documents Archive