Everyone got out safely in the William Street blaze, which broke out in a 1½-story wood-frame house off 12th Avenue shortly after midnight and quickly went to three alarms.
There were initial fears that residents were trapped after evacuees were seen using the fire escape of a neighboring building on East 22nd Street that sustained exterior damage.
A third building also was slightly damaged, responders said.
No injuries were reported, however.
PSE&G responded and cut gas and electricity to the block after having to dig into the street.
The fire was declared under control shortly before 2:30 a.m.
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