South County: If You Hear Sirens, It’s Only a Test

South Orange County residents who hear the high-pitched, steady wail of sirens this morning should not call 911. Local safety officials say it’s only a test of the San Onofre nuclear power plant’s emergency alert system.

Between 10 a.m. and noon today, 49 sirens within 10 miles of the plant will sound twice, for three to five minutes. The 120-decibel sirens are comparable to a loud rock concert, and their output overlaps to ensure that they are heard throughout San Clemente, Dana Point, San Juan Capistrano, some county land and Camp Pendleton.

The annual test is required by the Nuclear Regulatory Commission.

Plant operator Southern California Edison alerted city officials, school districts, residents and businesses to the test. In an emergency, residents should turn on their televisions or radios and await instructions. Depending on the type and severity of accident, they would be told to do nothing, to shelter in their homes with windows and doors closed and ventilation systems turned off, or to evacuate.