Athens remains at risk of another mass power blackout during next month's Olympics (search) if power consumption stays high because of the scorching heat, a chief overseer of Greece's electricity grid said Tuesday.

The warning was part of a nationwide investigation by engineers and experts seeking answers to Greece's worst power failure in decades, which crippled the southern half of the country for hours Monday and stunned Olympic organizers just a month before the games.

But the overall conditions that knocked out power to at least 7 million people cannot be fundamentally corrected before the Aug. 13-29 Games, said Evangelos Lekatsas, chairman of the Hellenic Transmission System Operators (search), which regulates the nation's flow of electricity.

A heat wave and heavy air conditioner use are key factors that could create another blackout during the games.

"Oh yes, if you make such assumptions there may be some problems," Lekatsas said.

A detailed study of the blackout is not yet available. But Lekatsas and others offered a general picture: a major system malfunction occurred as it tried to compensate for a crippled generating station near Athens. Millions of air conditioners were in use as afternoon temperatures reached 104 Fahrenheit.

The overburdened lines created a domino-effect shutdown over southern Greece and many islands. Power was mostly restored to Athens after three hours, but the lights did not return to some areas for seven hours.

Lekatsas said the reason for future worries is not a shortage of megawatts, but how they move through the network in Greece.

Most of the power generating facilities are in northern Greece, but half the country's 11 million people live in the Athens area or nearby. Regulating the long-distance electricity flow during peak demand times — like the current heat wave — raises risks of future mass blackouts, Lekstsas warned.

On Monday, a generator near Athens stopped working and forced other generators from northern Greece to bring more power to Athens. The grid, however, could not pump in juice quickly enough to cover the voltage drop, Lekatsas.

"This caused the whole problem ... the problem is that most of our generation is in the north and the load is in Athens, the south. So, it is very important to have generating units also in Athens," Lekatsas said.

But no major generating plants have been built in the Athens area for the Olympics, but several smaller stations are planned. In addition, five new substations are expected to begin operating next month to help distribute electricity.

Greek officials are counting heavily on nature to help out.

According to 13 years of data, the temperatures and electricity consumption are normally at their peak in Athens in the first two weeks of July, Lekatsas said. August tends to be a bit cooler, with average highs in the low 90s.

"We hope that also this will happen this year ... it will be improbable to have such high temperatures at the end of July or during August," Lekatsas said. "But I cannot be a prophet."

And this year, August electricity patterns also could be different.

Olympic organizers have encouraged Athenians to remain in the city rather than take the traditional August holidays. Meanwhile, more than 1 million Olympic spectators, athletes and others are expected.

"It is something that depends upon the temperature," he added. "It is only the air conditioning that does the problem."

Government leaders and power grid operators held emergency meetings to hammer out strategies to avoid another failure during the Olympics. But there also blame trading going on.

Government officials said the blackout was caused by human error. Greece's Public Power Corp. — and Olympic sponsor — said the fault rested with the state-run company that regulates the grids.

The transmission company operates independently of the Public Power Corp., which is about 55 percent owned by the state. The remaining stake is traded on the Athens Stock Exchange (search).

All Olympic venues have independent generators and other auxiliary power systems, but not all were in operation on Monday, said Claude Philipps, major events program director for Atos Origin, the technology firm handling results and other information distribution during the games.

"We have all the data here, to have second by second what happened ... We need more than one month to have a very clear picture of everything that happened," Lekatsas said.