A massive power failure swept the United States and southern Canada from the Great Lakes to the Eastern Seaboard yesterday, shuttering businesses, stranding commuters in elevators and subway cars, and leaving government officials bewildered as to the cause of the largest electrical outage in the nation's history.
The blackout struck just after 4 p.m. and quickly incapacitated traffic lights, airports, trains, computer systems and air conditioners throughout a broad swath from the Midwest to the Atlantic Ocean. Detroit, Cleveland, Toronto and New York were flooded with sweltering office workers who poured out of lifeless skyscrapers and subways into a teeming scene of urban confusion and discontent.
Maryland was mostly spared from the imbroglio, though the University of Maryland's College Park campus lost power for about 20 minutes. Gov. Robert L. Ehrlich Jr. referred to the outage as little more than "a pretty interesting exercise for us."
But northward into Canada and throughout much of the nation's most densely populated region, the wave of frustration and near-panic evoked memories of the 2001 terrorist attacks, with millions of Americans watching television images of stunned New Yorkers filing out of the city on foot. Reminiscent of New York's Sept. 11 lockdown, traffic was turned back at the bridges and tunnels entering Manhattan, and the outbound rush hour descended into gridlock.
"The whole time we were thinking, 'Maybe this is the first stage. Maybe something is going to happen after this,' " said Claire Mysko, 26, who was evacuated from her Wall Street office building and had to walk through hordes of commuters to her 14th Street apartment.
"It makes you wonder - was this terrorism or what?" said John Meehan, 56, exhausted after a 37-story descent from his Cleveland office tower.
Perhaps keen to those anxieties, officials in New York and other cities moved quickly to dispel any concern that terrorism was to blame - even as they confessed to having few clues about the cause. Several state and federal officials said no evidence of terrorism was found.
New York Mayor Michael R. Bloomberg pledged: "Tomorrow, we'll be back up to business as usual."
"The one thing I think I can say for certain is that this was not a terrorist act," President Bush said, adding that "slowly but surely we're coping with this massive, national problem."
While the cause was unclear, officials in the United States and Canada seemed to be focusing on an area along the New York/Canada border near Lake Erie as the possible root of the troubles - and disagreeing on which side of the border was at fault. American officials were skeptical of a Canadian claim that lightning triggered the cascade of events when it hit a power plant on the U.S. side of Niagara Falls.
A lightning strike or failed transformer can trigger a surge in power demand or destabilize the flow of power through the grid that supplies electricity to cities and homes across the nation, but the system is designed to absorb and compensate for such fluctuations.
"It happened in about 9 seconds," Michehl R. Gent, president of the industry-sponsored North American Electric Reliability Council, said on CNN. "The system is supposed to be designed so that doesn't happen." He said it is essential to find out why the grid collapse occurred so rapidly and was so widespread, with a loss of 10 percent of the electricity flowing east of the Rocky Mountains.
"We'll find out here what caused the blackout," Bush said. "But most importantly what we now need to do is fix the problem and to get electricity up and running as quickly as possible."
Airports in New York, Cleveland and southern Canada were closed, lacking the metal detectors and ticket counters necessary to stay in business. Air traffic control centers switched to backup power to guide in planes that were in the air, and service to the airports was being gradually restored as the day wore on.
Trains on Amtrak's busy Northeast rail corridor, which run on electricity, were halted north of Philadelphia.
In New York City, millions of people poured out of office buildings and the crippled subway system into a darkened streetscape that evoked memories of the 1977 blackout that plunged the city into two days of looting, fires and chaos. But Bloomberg said the latest blackout had prompted no significant fires and "no criminal activity of any size."
Consolidated Edison, which provides power to New York City, said late last night that bringing back all the city's lights was still a "several-hour process." Spokesman Michael Clendenin said ConEd was not sure all its customers would have power by morning.
The Long Island Power Authority said it had restored power to 150,000 of its 1.1 million customers by 10 p.m.
Still, New York officials were setting up emergency shelters for residents who could not return home yesterday evening and were cautioning people to stay calm, drink fluids, and turn off their lights and air conditioners to avoid an overload when power is restored.
"One of the big risks is that people die because of the heat and lack of water," Bloomberg said.
Hospitals throughout the powerless territory turned on generators and reported few difficulties treating patients. No injuries or deaths were immediately attributed to the blackout, and most areas seemed to be suffering more from inconvenience than outright danger.
Roller coaster riders at Six Flags over New England waited 20 minutes before park employs walked them off the stalled ride. Broadway shows were canceled, and the New York Mets postponed their night game against the San Francisco Giants, evacuating fans who had entered Shea Stadium.
JoAnne Matschulat of Anneslie was trying to take her two daughters and a friend to an Aaron Carter concert in Long Island last night and instead ended up in a warm Best Western Hotel lobby with a candle and a flashlight. "We have to kind of laugh at the whole thing and just hope we can get our flight out tomorrow," Matschulat said from the darkened hotel lobby last night, where there was no air conditioning. "You have to laugh because there's nothing you can do about it."
The outages also revealed the array of generators, backup systems and other safeguards that are installed in American business and government, many in response to the emergence of computer viruses and terrorism as potent 21st-century threats.
In Albany, N.Y., city officials dusted off their Y2K emergency plan and boosted the staffing of police and counselors at senior centers. "We were prepared for this," said Mayor Jerry Jennings. "It's obviously kicked us into another gear."
Hospital workers in Cleveland said that expectant mothers were enduring delivery rooms without air conditioning but that generators had restored vital systems and equipment. Trading on the New York Stock Exchange had ended by the time the power went out, and the Connecticut computer facility that runs all the systems for the Nasdaq market was running on backup power, which spokesman Wayne Lee said could continue for days.
Nine nuclear reactors in four states automatically shut down when their safety systems detected instability in the power grids, according to the Nuclear Regulatory Commission. Diesel generators then kicked in to power the reactors' safety systems.
Telephone service in the region was largely unaffected by the blackout thanks to battery-powered equipment and backup generators, according to spokesmen for Verizon Communications Inc. and AT&T; Corp. Customers with cordless phones or other equipment that required electricity could not place calls, but their service was not affected, the companies said.
The darkness provoked a spike in the volume of calls, however, and strained the system, clogging land lines and cellular services and causing some callers to hear faint busy signals or other interference. AT&T; reported that its nationwide network was receiving about 2.6 million calls every five minutes late yesterday afternoon, compared with about 2 million in a typical day.
"We just know from every experience we've had that people get on the phones, they talk a lot, and they tend to talk longer," said Eric Rabe, a spokesman for Verizon who was working in the dark without air conditioning yesterday in his Manhattan office. "More people are talking, and so the network gets used to capacity."
The Internet and major Web sites also felt only a marginal impact, according to Keynote Systems, a Silicon Valley company that measures Internet performance. The company reported that some news Web sites were taking longer to download, probably because their backup power systems were set up for shorter power outages.
Flanked by Baltimore Mayor Martin O'Malley and city Police Commissioner Kevin P. Clark at a news briefing last night, Baltimore Gas and Electric Co. spokesman Robert L. Gould said that none of the utility's 1.14 million customers in Central Maryland were inconvenienced by yesterday's blackouts and that company officials would continue to monitor the situation.
"Everything is very stable right now," Gould said at police headquarters, noting that there were systems in place that prevented the outage from affecting Maryland. O'Malley said the city's emergency preparedness center was not activated, but emergency personnel were on alert.
"This is a good case study for us for the future," O'Malley said last night. "As the people of New York pull together and deal with this, that will be a good lesson for us as well."
Sun staff writers Stacey Hirsh, Marego Athans and Johnathon E. Briggs and the Associated Press contributed to this article.