In voluntary compliance with the HSPD, Central City and Liberty County have adopted the National HSAS to trigger certain preparedness activities and disseminate information about the risks of terrorist threats. The system is a color-coded set of graduated threat conditions, with a higher probability of attack associated with each new level:

• Low/Green indicates a low threat of terrorist attack;
• Guarded/Blue indicates a general risk condition;
• Elevated/Yellow indicates a significant risk;
• High/Orange indicates a high risk; and 
• Severe/Red indicates a severe risk of terrorist attack.

Risk includes both the probability of the occurrence of an attack and its potential gravity. The local law enforcement community has the primary responsibility for conducting continuous risk assessments. However, other entities such as public health and health care organizations are crucial in anticipating and detecting potential biological threats. Threat condition levels may be set for the entire Nation or specific geographical regions based upon the available intelligence information.

The assignment of threat levels prompts the implementation of various operational conditions in order to reduce vulnerabilities and increase response capabilities of public safety and support agencies. The county also posts the current threat condition level on its emergency information website in order to keep the public informed of existing conditions and to provide an opportunity for citizens to better prepare for potential emergencies.