A test of the San Onofre Nuclear Generating Station Community Alert Siren System is scheduled for Wednesday, Oct. 21, 2009, from 10 a.m. to noon. All sirens near the San Onofre Nuclear Generating Station will be sounded multiple times for about three minutes each time.  Motorists traveling on I-5 may hear the sirens. No response action is necessary. This is only a test.