Blackout report points to Ohio

Experts from eight states and Canada met in private recently to evaluate the report, which the U.S. Energy Department plans to release Nov. 18, people involved in the investigation said. The report is expected to lay out the root causes of the event, with a separate report proposing solutions to come later.

The report, drafted by an aide at the Federal Energy Regulatory Commission, will likely leave for later the question of why the blackout stopped where it did, investigation participants said.

Investigators have established a chronology of events that day, collecting data from hundreds of digital fault recorders, electronic devices that track when power lines or generators take themselves out of service.

Inquiry participants said engineers had identified the failure of FirstEnergy operators in Akron, Ohio, to react properly after nearby transmission lines failed, one sagging into a tree, causing a short circuit that made the line disconnect itself from the grid.

It was not the loss of the initial lines that caused the lights to go out from Detroit to New York City to Toronto, because lines frequently fail without interrupting service, experts say. But it was the failure of the operators to perform a crucial analysis and then, if necessary, reconfigure the system.