That began a series of power gyrations as the Ohio-Michigan electric grid system tried but failed for more than an hour to recover.

And then the blackout began.

It first hit Lansing, Mich., at 4:09:02 p.m., at two General Motors plants there.

That was the first indication of major trouble, according to the FBI and a private industry log of power grid incidents obtained by ABCNEWS.

"Once that disturbance occurred, shortly after that, about four seconds after that, we saw another disturbance of similar magnitude in nearby locations and then we started seeing ripple effect," said Deepak Divan, CEO of Softswitching Technologies.

Four seconds later, at 4:09:06, the power crash skipped to suburban Cleveland, skipping along the interconnected Ohio-Michigan power grid.

A second major outage was registered at another GM plant, in Parma, Ohio, the pivotal point in the blackout, according to FBI investigators.

Spread Too Far

The Ohio power company failed to separate from the national electric grid, as it was supposed to and as Michigan did. Thus the cascade of problems was sent on to New York.

"The system is designed to isolate itself to protect that area, to have the area go down and have the rest of the system survive. And instead it spread further and longer than it should have," said Michehl R. Gent, president and CEO of the North American Electric Reliability Council.

A spokesman for the Ohio power company, FirstEnergy Corp., said it had followed all proper procedures but would not comment specifically on whether it had triggered the huge blackout by failing to separate.

"If they had separated you might have seen a region in Ohio area that would have been without power, but you would not have seen it in almost a national scale, as we did," Divan said.