Firefighters quickly got to the Third Street address off Essex Street shortly before 8:30 p.m. and had the fire under control in barely a half-hour.
They limited the fire damage to the first floor, where the blaze apparently began, and the second floor, which sustained heavy smoke damage.
No injuries were reported.
Mutual aid responders included firefighters from Clifton, Paterson and Wallington.
City fire officials were investigating the cause.
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