A group of federal agencies will lead a nationwide test of the Emergency Alert System at 2 p.m. Wednesday. The test will involve broadcast radio and television stations, cable television, satellite radio and television services across all U.S. states and territories. The agencies conducting the test include the U.S. Department of Homeland Security’s Federal Emergency Management Agency, the Federal Communications Commission and the National Oceanic and Atmospheric Administration. The test is expected to last more than 3 minutes. The public will hear “this is a test” during the audio message.