The Nation requires a Homeland Security Advisory System to provide a comprehensive and effective means to disseminate information regarding the risk of terrorist acts to Federal, State, and local authorities and to the American people. This system provides warnings in the form of a set of graduated "Threat Conditions" that increase as the risk of the threat increases. At each Threat Condition, Federal departments and agencies implement a corresponding set of "Protective Measures" to further reduce vulnerability or increase response capability during a period of heightened alert.

This system is intended to create a common vocabulary, context, and structure for an ongoing evaluation of the threats that confront the homeland and the appropriate measures that should be taken in response. It seeks to inform and facilitate decisions appropriate to different levels of government and to private citizens at home and at work.

The Homeland Security Advisory System has five Threat Conditions, each identified by a description and corresponding color.  The higher the Threat Condition, the greater the risk of a terrorist attack. Risk includes both the probability of an attack occurring and its potential gravity. Threat Conditions are assigned by the Attorney General in consultation with the Assistant to the President for Homeland Security. Except in exigent circumstances, the Attorney General seeks the views of the appropriate Homeland Security Principals or their subordinates, and other parties as appropriate, on the Threat Condition to be assigned. Threat Conditions may be assigned for the entire Nation, or they may be set for a particular geographic area or industrial sector. Assigned Threat Conditions are reviewed at regular intervals to determine whether adjustments are warranted.

The assignment of a Threat Condition prompts the implementation of an appropriate set of Protective Measures. Protective Measures are the specific steps an organization takes to reduce its vulnerability or increase its ability to respond during a period of heightened alert. The authority to craft and implement Protective Measures rests with the Federal departments and agencies. Department and agency heads are responsible for developing their own Protective Measures and other antiterrorism or self-protection and continuity plans, and resourcing, rehearsing, documenting, and maintaining these plans. Additionally, they are responsible for taking all appropriate proactive steps to reduce the vulnerability of their personnel and facilities to terrorist attack.

The Director of Central Intelligence (CIA) and the Attorney General ensure that a continuous and timely flow of integrated threat assessments and reports is provided to the President, the Vice President, Assistant to the President and Chief of Staff, the Assistant to the President for Homeland Security, and the Assistant to the President for National Security Affairs. Whenever possible and practicable, these integrated threat assessments and reports are reviewed and commented upon by the wider interagency community.

A decision on which Threat Condition to assign integrates a variety of considerations. This integration relies on qualitative assessment, not quantitative calculation. Higher Threat Conditions indicate greater risk of a terrorist act, with risk including both probability and gravity. Despite best efforts, there can be no guarantee that, at any given Threat Condition, a terrorist attack will not occur. An initial and important factor is the quality of the threat information itself. The evaluation of this threat information includes, but not be limited to, the following factors:

1. To what degree is the threat information credible?
2. To what degree is the threat information corroborated?
3. To what degree is the threat specific and/or imminent?
4. How grave are the potential consequences of the threat?

Threat Conditions and Associated Protective Measures

The world has changed since September 11, 2001. We remain a Nation at risk to terrorist attacks and will remain at risk for the foreseeable future. At all Threat Conditions, we must remain vigilant, prepared, and ready to deter terrorist attacks. The following Threat Conditions each represent an increasing risk of terrorist attacks. Beneath each Threat Condition are some suggested Protective Measures, recognizing that the heads of Federal departments and agencies are responsible for developing and implementing appropriate agency-specific Protective Measures:

1. Low Condition (Green)   This condition is declared when there is a low risk of terrorist attacks. Federal departments and agencies should consider the following general measures in addition to the agency-specific Protective Measures they develop and implement:
   1. Refining and exercising as appropriate preplanned Protective Measures;
   2. Ensuring personnel receive proper training on the Homeland Security Advisory System and specific preplanned department or agency Protective Measures; and
   3. Institutionalizing a process to assure that all facilities and regulated sectors are regularly assessed for vulnerabilities to terrorist attacks, and all reasonable measures are taken to mitigate these vulnerabilities.
2. Guarded Condition (Blue)   This condition is declared when there is a general risk of terrorist attacks. In addition to the Protective Measures taken in the previous Threat Condition, Federal departments and agencies should consider the following general measures in addition to the agency-specific Protective Measures that they will develop and implement:
   1. Checking communications with designated emergency response or command locations;
   2. Reviewing and updating emergency response procedures; and
   3. Providing the public with any information that would strengthen its ability to act appropriately.
3. Elevated Condition (Yellow)   An Elevated Condition is declared when there is a significant risk of terrorist attacks. In addition to the Protective Measures taken in the previous Threat Conditions, Federal departments and agencies should consider the following general measures in addition to the Protective Measures that they will develop and implement:
   1. Increasing surveillance of critical locations;
   2. Coordinating emergency plans as appropriate with nearby jurisdictions;
   3. Assessing whether the precise characteristics of the threat require the further refinement of preplanned Protective Measures; and
   4. Implementing, as appropriate, contingency and emergency response plans.
4. High Condition (Orange)   A High Condition is declared when there is a high risk of terrorist attacks. In addition to the Protective Measures taken in the previous Threat Conditions, Federal departments and agencies should consider the following general measures in addition to the agency-specific Protective Measures that they will develop and implement:
   1. Coordinating necessary security efforts with Federal, State, and local law enforcement agencies or any National Guard or other appropriate armed forces organizations;
   2. Taking additional precautions at public events and possibly considering alternative venues or even cancellation;
   3. Preparing to execute contingency procedures, such as moving to an alternate site or dispersing their workforce; and
   4. Restricting threatened facility access to essential personnel only.
5. Severe Condition (Red)   A Severe Condition reflects a severe risk of terrorist attacks. Under most circumstances, the Protective Measures for a Severe Condition are not intended to be sustained for substantial periods of time. In addition to the Protective Measures in the previous Threat Conditions, Federal departments and agencies also should consider the following general measures in addition to the agency-specific Protective Measures that they will develop and implement:
   1. Increasing or redirecting personnel to address critical emergency needs;
   2. Assigning emergency response personnel and pre-positioning and mobilizing specially trained teams or resources;
   3. Monitoring, redirecting, or constraining transportation systems; and
   4. Closing public and government facilities.