The fire broke out at 221 Emmet Street at around 5:45 a.m. Tuesday.
The vacant 3-story building on fire was in danger of collapse, and other structures were being threatened.
Firefighters were being hampered by lack of water pressure. They were still working to put the blaze under control more than three hours later.
A neighboring building at 219 Emmet Street was damaged by the fire.
No injuries have been reported.
MORE NEWS: Chris Harrison 'stepping aside' from role as 'Bachelor' host after defending controversial contestant
* Get Eyewitness News Delivered
* More New Jersey news
* Send us a news tip
* Download the abc7NY app for breaking news alerts
* Follow us on YouTube
Submit a News Tip