The incident happened just two blocks from 41st Street and Lexington, where a Con Ed steampipe exploded last July, causing a woman to die from a heart attack and injuring 41 others.
About 33 residents from five small apartment buildings lost power and had to be evacuated after the 4:25 a.m. incident on Thursday. They were allowed to return to their homes at 9:45 a.m., but still do have power.
The Fire Department and utility said the residents were evacuated due to high levels of carbon monoxide caused by the manhole fire. There also was a simultaneous, unrelated natural gas leak in the same underground area, said Con Edison spokesman Chris Olert.
Olert said it was hoped all the problems could be resolved sometime Thursday.
He said the cause of the smoldering cables will be investigated.
