Authorities say a warning siren that went off near the San Onofre nuclear power plant was a false alarm.
The Orange County Sheriff's Department says the alarm from Tuesday morning prompted about 50 calls from concerned residents.
Gil Alexander of Southern California Edison says a siren went off around 4:30 a.m. Tuesday in San Clemente and continued for about 30 minutes before technicians shut it off.
The siren is one of 52 in and around the nuclear plant that are supposed to alert people in an emergency to turn on their radios or TVs for more news.
Alexander says there wasn't any emergency and the siren malfunctioned. He says false alarms are rare: The last one occurred 15 years ago.
