By Christine Haughney
Washington Post Staff Writer
Thursday, August 14, 2003; 6:27 PM

NEW YORK, Aug. 14 -- A massive power outage shut down businesses, disrupted travelers and left millions of people from Manhattan to Detroit and north into Canada without electricity on this hot August afternoon.

Mayor Michael Bloomberg announced at a news briefing shortly before 6 p.m. that officials from ConEdison power company told him that power was slowly being restored. "It will take a decent amount of time, hours not minutes," he said.

Bryan Lee, a spokesman for the Federal Energy Regulatory Commission told the Reuters news service that the problem was caused by an outage at a Manhattan power plant that destabilized the power grid about 4 p.m.. "We have no indication that there is any terrorism involved," Lee said.

The FBI also said it was not related to the recent computer virus that has been sweeping the Internet. "There is no basis to speculate that the power outage is related to the Internet worm that has been infecting and crashing computers worldwide since Monday afternoon," said FBI spokesman Bill Murray.

There were not immediate reports of violence or fires, Bloomberg said.

In downtown New York, people were forced to leave their office towers by stairwells and many were attempting to walk home this afternoon. The subway system was not working and there were reports of trains trapped in tunnels. Most businesses were closed, except for a few cafes. Many people were gathering around cars on the streets to listen to radio reports about the power outage.

The federal Department of Transportation said that passenger screening machines are inoperable at the three major airports here, Laguardia, Newark and John F. Kennedy, so officials cancelled all takeoffs. Planes already en route were allowed to land, however. Airports in Ottawa, Toronto and Cleveland were following the same procedures. Detroit was reporting no stoppages.

Penn Station and Grand Central Station are shut down in New York, also. Amtrak officials said they are operating limited service from Washington to Newark, but is discouraging travel north of Philadelphia. They are operating no trains in or out of Penn Station. Although it has power from near New Haven to Boston, it has cancelled all service from Newark to Boston because trains cannot get into New Haven. One is stranded there now, almost within sight of the station, officials said.

The only other stranded train is an Acela Express headed to Washington that is holding at the Old Saybrook, Conn., station.

Metro North also said it was shut down completely. Some trains were reported stuck between stations. New Jersey Transit also said it had no signals and was shut down, even diesel trains.

Thousands of people took to the streets trying to get home in the 90 degree heat. Television broadcasts showed major roads and bridge ramps clogged with pedestrians.

At Interbrand, a brand consulting firm at 130 5th Ave. in New York, employees initially hoped that the outage was just temporary but when it became clear that it was a bigger problem, it brought back some memories of the problems that followed the terrorist attacks on New York. The office has not moved its space since then attacks on Sept. 11, 2001, where employees could see a plane hit one of the World Trade Center towers.

"People are nervous. I would say this is very reminiscent of two years ago," said Lisa Marsala, director of public relations.

The office manager at Interbrand passed out flashlights as people made plans for what to do next. Some wanted to go home, but the subways weren't running. Others offered their Manhattan apartments as a waiting space for those who don't live in the city.

Meanwhile, a happy hour to be celebrated for the summer interns' last day changed its focus. "Now they are inviting us to the cafe for beer and wine to relieve stress, tension and fear," said Marsala. "And the IT team is cursing."

The blackout hit just after the closing bell at the New York Stock Exchange, complicating the overnight electronic "paperwork" that sorts out all the billions of dollars and millions of shares that change hands daily. All the stock exchanges have not only backup power supplies, but also backup computer systems. If power is still off tomorrow in Connecticut where the Nasdaq Stock Market's main computers are located, the market has duplicate backup systems in Rockville.

The outage had repercussions on businesses throughout the affected area. General Motors said that about 20 of its plants were shut down, according to John Anderson of the Electricity Consumers RESOURCE COUNCIL, which represent large industrial users of power. "I know it's going to have a significant impact on business," he said.

The outage caused some communication problems also. Verizon said both its wireless and landline telephone network is working and should continue to work as long as the back-up electrical systems continue to operate. However, Verizon said that there has been some congestion on the phone lines as consumers flooded the phone lines after the outage and encountered fast busy signals, a sign the network was overloaded.

"The network is working but carrying more signals that it is used to," said spokesman Eric Rabe. Consumers need to be patient and persistent, he added.

Long-distance firm AT&T said that its normal load of 2 million calls every five minutes jumped to 2.6 million shortly after the outage and has continued at that rate since the outage, with many calls coming from out of the affected area to check on those in Northeast.

"A thirty percent blip is no problem for us," said AT&T spokesman Dave Johnson.

Staff writers Sara Goo, Martha Hamilton, Jerry Knight, Caroline Mayer, Don Phillips, and Greg Schneider and Robert MacMillan of washingtonpost.com also contributed to this report.