Blackout Cause 'Very Complex'

The investigation into what triggered last week's eight-state, two-nation blackout is zeroing in on an area just south of Cleveland.

Two hours before New York went dark, a coal-fired power plant in northeast Ohio shut down and a number of high-voltage power lines south of Cleveland failed. But investigators can't yet say the Ohio outages triggered the massive power loss that followed, reports CBS News Correspondent Bob Orr.

"We know the Midwest was a link in the chain that led to this reaction. What we don't know fully yet is whether they were the first link, the second, link or some other link in the chain," said Stephen Allen of the Northeast Power Coordinating Council.

FirstEnergy Corp., which owns the Ohio plant and serves four million customers in three states, denies it's to blame.

In a statement issued Monday, FirstEnergy said: "What happened is a very complex situation, far broader than the power line outages we experienced on our system."

It is complex: After the power outages around Cleveland, plants and power lines shut down in a lightning-quick domino series of failures that left 50 million people in eight states and Canada without electricity.

Now investigators are trying to recreate a timeline, precise to a fraction of a second, to determine what failed, in which order and for what reason.

"What we're dong is we're taking a look at all the logs. We've collected data, thousands and thousands and thousands of data points, probably 100,000 data points. And we're sorting through this, putting it in chronological order, trying to make sense out of it," said Michehl Gent, president of the North American Electric Reliability Council.

Gent told CBS News Correspondent Sharyl Attkisson he considers the chance of any kind of terrorism remote and has narrowed the list of possible causes to two: either a system design flaw, or "some electric utility or operator was not playing by the rules."

The rules, Attkisson explains, were adopted by the industry to try to keep the delicate balance of power; there's more electricity generated than lines to deliver it, so there's a constant fight to keep lines from overloading. As long as companies follow the rules there shouldn't be a blackout. But it turns out the rules are voluntary, with no real punishment for violators.

Officials say that in some ways safeguards built into the giant U.S. power grid did work – they stopped the blackout before it spread to Boston and Washington. But energy experts say the grid is vulnerable and this could happen again.

"We need to invest in facilities and frankly we need to invest in technologies as well. Neither will solve the problem by itself," said Mike Naeve, a former Federal Energy Regulatory Commission member.

But first, investigators need to know precisely what went wrong. They hope to have a good idea in seven to ten days.

President Bush, who has been criticized by Democrats for neglecting electric power in his energy priorities, told advisers Monday he wants the reason behind last week's power blackout found "as quickly as possible" so needed changes can be made.

White House press secretary Scott McClellan said the president, who is in Crawford, Texas, "emphasized the need to find out what caused the blackout and to do so as quickly as possible" in a telephone call to Energy Secretary Spencer Abraham.

Abraham, who along with his Canadian counterpart, is heading a special U.S.-Canadian task force to investigate the blackout.

Meanwhile, with power finally restored, millions of people headed back to work Monday for the first time since the lights went out, riding trains and elevators idled by the outage and getting a closer look at the aftermath of the biggest blackout in U.S. history.

In Detroit, residents returned to drinking straight from the tap, and New Yorkers started the workweek with the nation's largest mass transit system running on schedule.

"We're off to an auspicious start," Dennis Selmont said at the train station in Milford, Conn. "There's no one standing on the platform telling us there are no trains."

However there were lingering reminders of last week's problems: garbage cans overflowing with spoiled food, continuing water-boil warnings and a flood of questions about how such a massive blackout could have happened.