Anxiety is rising over the test that may last for up to 3 minutes on Wed.
The test occurs at 2 p.m. EST Wed., Nov. 9, and may last over three minutes The test will be transmitted via television and radio stations within the U.S., including Alaska, Hawaii, the territories of Puerto Rico, the U.S. Virgin Islands, and American Samoa.
It's only a test, but nerves are somewhat frayed over the first nationwide exercise of the system designed to alert Americans of national emergencies.
The test occurs at 2 p.m. EST Wed., Nov. 9, and may last over three minutes -- longer than the typical 30 seconds or one minute for most broadcast test messages.
According to a message being circulated by local school and government officials, there is "great concern in local police and emergency management circles about undue public anxiety over this test."
"The test message on TV might not indicate that it is just a test," according to one email being circulated by a Washington area school district.
"Fear is that the lack of an explanation message might create panic. Please share this information with your family and friends so they are aware of the test."
The test is being conducted jointly by the US Department of Homeland Security, the Federal Emergency Management Agency, the Federal Communications Commission and the National Weather Service.
"We're asking everyone to join us by spreading the word to your neighbors, co-workers, friends and family... please remember: don't stress; it's only a test," FEMA said in a blog post.
The test is part of the Emergency Alert System designed to transmit, via TV and radio, emergency alerts and warnings regarding weather threats, child abductions and other types of emergencies, according to officials.
While state and local tests already take place frequently, a simultaneous, nationwide test of the national EAS "emergency action notification" code has never occurred.
"Because there has never been an activation of the Emergency Alert System on a national level, FEMA views this test as an excellent opportunity to assess the readiness and effectiveness of the current system," said Damon Penn, FEMA's Assistant Administrator of National Continuity Programs in a press release.
"It is important to remember that this is not a pass or fail test, but a chance to establish a baseline for making incremental improvements to the Emergency Alert System with ongoing and future testing. It is also important to remember that the Emergency Alert System is one of many tools in our communications toolbox, and we will continue to work on additional channels that can be a lifeline of information for people during an emergency," Penn added.