Terminal High-Altitude Area Defense (THAAD)
Permanent Stationing in Guam Environmental Assessment



In April 2013, the U.S. Army deployed a THAAD missile battery to Guam on an emergency basis in response to missile threats by North Korea. Since the temporary deployment of the THAAD battery in 2013, the Department of Defense validated the enduring requirement for a THAAD battery in Guam to ensure continued defense of the homeland against existing and emerging missile threats by potentially hostile states in the region, as mandated in Title 10 of the U.S.C., Armed Forces.

Prior to the emergency emplacement of the U.S. Army’s THAAD battery in April 2013, its
current location on Northwest Field (NWF) at Andersen Air Force Base served as a key asset for cargo parachute operations (airborne training). The current location of the THAAD battery forced airborne training activities and exercises to other locations in the region.

Proposed Action

The Proposed Action for the THAAD EA is to maintain the THAAD battery permanently in Guam. The current battery has been operating as an expeditionary (temporary) mission at
Andersen AFB since its deployment in April 2013.


The THAAD EA analyzes two alternatives, and a No Action Alternative, to the Proposed
Action. Both alternatives include:

  • activities that occurred during the emergency deployment and subsequent adaptations of the THAAD battery; and
  • proposed modifications and improvements for long-term system operations.

The Preferred Alternative also includes site improvements and operational changes made to the current THAAD battery, as well as expansion of the current cargo drop zone (CDZ) into adjacent areas on Northwest Field (NWF).


What is THAAD?

The Terminal High-Altitude Area Defense (THAAD) system is a transportable, rapidly deployable capability to intercept and destroy ballistic missiles inside or outside the atmosphere during their final, or terminal, phase of flight. See the Department of Defense’s website on the THAAD system for more information:


What is NEPA?

The National Environmental Policy Act (NEPA) of 1969 was enacted to address concerns about environmental quality. NEPA's main objectives are as follows:

  • Ensure that Federal agencies evaluate the potential environmental impacts of proposed programs, projects, and actions before decisions are made to implement them
  • Inform the public of proposed Federal activities that have the potential to affect the human environment, including the natural and physical environments
  • Encourage and facilitate public involvement in the decision-making process

NEPA requires a Federal agency to analyze impacts from a proposal and its alternatives, and provides the public with opportunities to participate in the process.

What is an EA?

An environmental assessment (EA) is a public document that provides a structured approach to environmental impact analysis, as mandated by Council of Environmental Quality regulations for NEPA. An EA is a detailed public document describing a proposed action, all alternative actions that were considered, and the environmental impacts of implementing the Proposed Action and reasonable alternatives.

The Council of Environmental Quality was established to implement and oversee Federal policy in the NEPA process. The CEQ regulations specify that an EA be prepared to provide evidence and analysis for determining whether to prepare a Finding of No Significant Impact (FNSI) or to prepare an Environmental Impact Statement (EIS). The EA aids in an agency’s compliance with NEPA when an EIS is unnecessary and facilitates preparation of an EIS when one is required.

What is a FNSI?

A Finding of No Significant Impact (FNSI) documents an agency’s decision after completion of an EA that the proposal would not result in significant impacts to the environment and that preparation of an EIS is not necessary.

What is the THAAD EA schedule?

The updated THAAD EA was available for public review and comment from March 17, 2017 until April 17, 2017. Comments received during the public comment period were considered, as appropriate, in the development of the Final EA. The Final EA was completed and the FNSI signed on April 25, 2017. They can be viewed on the "Documents" page of this website.

Who should I contact if I have more questions about the THAAD EA?

For further information or questions on the THAAD EA, please contact:

U.S. Army Space and Missile Defense Command/Army Forces Strategic Command
Attention: SMDC-ENE (Mark Hubbs)
PO Box 1500
Huntsville, AL 35807-3801