Is that a siren I hear? What do I do?

Whether it is an ambulance siren wailing near the intersection you are about to enter, a siren from the fire truck that is passing you or a siren mounted on a pole near your home – you need to be prepared to respond when you hear it.

Since most people are less familiar with the pole-mounted sirens that are associated with nuclear power plants, below are questions and answers that you may find useful if you live in the 10-mile radius of a nuclear plant.

Why are there sirens near a nuclear power plant?

Since 1980, a federal law requires every utility that owns a nuclear power plant in the U.S. to have emergency sirens (in addition to an emergency response plan) as a condition of its license to operate the plant. The sirens must be located at distances related to the population within a 10-mile radius of the nuclear plant called the Emergency Planning Zone (EPZ).

The Nuclear Regulatory Commission (NRC) regulates and monitors operation of all U.S. nuclear plants. While an accident at a nuclear plant is highly unlikely, it is possible. The potential danger to the public is the release of and exposure to radiation. There are many factors that affect the effect on the public, such as distance, weather conditions, wind direction and wind speed.

Alerting the public to potential emergencies at a nuclear plant is a priority. The sirens in the EPZ of a nuclear plant serve as an outdoor warning system. If an emergency at the plant requires sirens to be sounded, these sirens would sound repeatedly. If you hear a loud, steady sound coming from one of the sirens around the nuclear plant, tune to a local radio or television station for more information on what you might need to do.

What do these sirens sound like?

While there may be various siren sounds, take time to find out how the sirens for your nuclear station sound. Duke Energy schedules full volume siren tests on Wednesday mornings to minimize inconvenience to plant neighbors. The tests, which last up to three minutes, are conducted to make sure each of the numerous sirens works properly. Tests may be performed more than once to ensure each siren works properly.


 Listen to a sample siren test.


If I hear one, what am I supposed to do?

Emergency warning sirens are simply an outdoor notification to alert you to listen to your local radio or television station to learn more on what, if anything, you should do. The sirens are tested regularly to ensure they work properly and also undergo preventive maintenance. Hearing a siren does not mean that you should evacuate the area. During siren tests, the public does not need to take any action.

How do I know when the siren test day is?


Duke Energy annually mails emergency information to every household in the EPZ of its nuclear plants. This is in the form of a calendar and includes important emergency planning information, as well as general information about radiation and how to prepare for a nuclear emergency. It also includes the dates for siren testing. Dates are also available here.

State and county officials and Duke Energy want you to be prepared and know what to do in the unlikely event of an emergency at one of the area nuclear plants. Please keep your annual calendar in a place where you can readily find it and be familiar with its contents.


What if I hear a siren and it is not on the normal “test” day?

If you hear sirens and are not sure if it is a test or an emergency, tune to a local radio or television station listed in the calendar sent by Duke Energy. During an emergency, these stations stop regular programming to provide information to the public. The siren will sound repeatedly at three-minute intervals, if there is an emergency. It is important to note that sirens may not necessarily be heard inside homes or businesses due to televisions or radios already playing. Contact your local county emergency management office if you have questions related to hearing a siren.

Who owns and maintains the sirens?

Duke Energy owns and maintains the sirens. They are regularly tested to make sure they work properly. There are several types of siren tests performed at different times – some weekly, monthly or quarterly. “Silent tests” confirm the radio feedback system receives a signal. A “low volume growl” test verifies proper operations as well as radio feedback signal receipt, and results in a momentary sound, or growl, of the siren.

Who activates the sirens?

Your county emergency management officials, in coordination with Duke Energy, determine public protective actions. This includes activation of emergency warning sirens.

How will I know there is an actual emergency?

Although highly unlikely, if there were an emergency at a nuclear plant, sirens are the primary outdoor warning system for alerting the public. Duke Energy would immediately notify federal, state and local authorities of plant conditions. If needed, these authorities could activate pole-mounted sirens located in the plants’ EPZ.

Is there anything else I would need to do?

Some of your neighbors may need assistance in an emergency. Please check on them, ensure they are aware of the emergency and have emergency plans in place.

Are the sirens used for warning about anything else such as weather?

Sirens provide another layer of protection that can be utilized to ensure public health and safety during any type of emergency in the community or at a nuclear plant. County emergency management officials determine when to activate the sirens to keep the public safe.

For more information, visit our nuclear emergency preparedness website.

Comments (1)

Posted July 15, 2016 by James Greenidge
In all my travels, I can count the oil and gas and chemical facilities (proven neighborhood killers) with a siren or horn on less than one hand.

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