The Emergency Broadcast System (EBS), sometimes called the Emergency Action Notification System (EANS), was an emergency warning system used in the United States. It was the most commonly used, along with the Emergency Override system. It replaced the previous CONELRAD system and was used from 1963 to 1997, at which point it was replaced by the Emergency Alert System.

An emergency population warning is a method where by local, regional, or national authorities can contact members of the public to warn them of an impending emergency. These warnings may be necessary for a number of reasons, including:Weather emergencies such as tornadoes, hurricanes, and ice storms. Geological disasters such as earthquakes, landslides, volcanic eruptions, and tsunamis. Industrial disasters such as the release of toxic gas or contamination of river water. Radiological disasters such as a nuclear plant disaster. Medical emergencies such as an outbreak of a fast-moving infectious disease. Warfare or acts of terrorism.