The United States plans to create a national emergency alert system that utilizes text messages that will be delivered to mobile phones. CTIA estimates over 48 billion text messages are sent each month, so regulators believe this is a good medium to use when there is a national or regional emergency.

In 2006, the United States passed the Warning Alert and Response Network Act, which requires upgrades to the nation’s emergency alert system. The law requires the Federal Communications Commission (FCC) to develop ways to alert the public about emergencies.

“The ability to deliver accurate and timely warnings and alerts through cellphones and other mobile services is an important next step in our efforts to help ensure that the American public has the information they need to take action to protect themselves and their families prior to, and during, disasters and other emergencies,” the commission chairman, Kevin J. Martin, said after the plan was approved.

Participation in the text message service will be voluntary for both carriers and customers. Any emergency messages sent to customers will be free and most in the industry support the service.

There will be three categories of emergencies that trigger a text alert. The first is a national alert from the president and involves national emergencies like terrorist attacks or natural disasters. The second involves imminent threats that can be predicted. This includes things like hurricanes or other predictable disasters. The third category would alert citizens about child abductions, which is currently called an Amber alert.

To differentiate an emergency alert from other messages, a unique audio signature or vibration cadence will be broadcast along with the message. The service may be up and running as early as 2010.