A major power outage swept through Los Angeles Monday afternoon, trapping people in elevators during the lunch hour, snarling traffic and prompting the Los Angeles Police Department to go into tactical alert.

The outage started when a Los Angeles Department of Water & Power employee inadvertently cut a power cable at a DWP receiving station. That in turn tripped off power shutdowns at several distributing stations serving Los Angeles and some surrounding cities, including Burbank and Long Beach.

Terrorism was ruled out as a cause for the cut power line, according to radio reports quoting L.A. Fire Department officials. On Sunday, L.A. was named along with Melbourne, Australia, in a threat from an Al-Qaeda member.

DWP officials said in broadcast reports that the outages started at 12:36 p.m. in the San Fernando Valley and then spread to Hollywood, downtown Los Angeles, the Wilshire corridor, West Los Angeles as well as parts of South Los Angeles, Wilmington and Long Beach. At its height, the outage affected about 1.5 million customers, nearly one-half of all DWP customers.

Power was out for approximately a half-hour in most places; by 3 p.m., DWP officials said power had been restored to about 90 percent of the city. They said power would be restored to the remaining parts of the city shortly after 5 p.m.

After power began to return earlier in the day, city fire officials warned all citizens to stay out of elevators until power stabilized. Los Angeles Fire Department crews conducted scores of rescues of people trapped in elevators throughout the afternoon.

Los Angeles International Airport and Bob Hope Airport in Burbank were operating normally using emergency backup power. But the power failure did cause a problem at the Conoco-Phillips refinery in Wilmington when a planned burnoff of fuel was in progress and smoke backed up.