Go to: In March 2002, Homeland Security Chief Tom Ridge unveiled a new color-coded threat advisory system for the United States. The idea was to create a way to convey the risk of terrorist attacks to federal, state, local authorities and the American people. The coded warning system has five levels that is associated with a suggested protective measure and will trigger specific actions by federal agencies and local law enforcement. Click on each "code" below to see details of the protective measures characterized by the Homeland Security Advisory System.