Problems with at least three underground Com-Ed vaults on the near north side, knocked out power to several high rises.
It happened around 1:00 a.m. near the 1000 block of N. Dearborn.
A man working at a business near by says it all started with a blast that shook buildings in the area.
ComEd says there was no fire or explosion.
It was a breach in one of the underground lines.
Power is still out to two buildings.
No injuries were reported.