The building, managed by the Newark Housing Authority, was all but destroyed about 6 p.m. Friday after an explosion rocked the building. The cause of the blast is under investigation.
The walls of the building were blown off, leaving a refrigerator and furniture on full display.
Valery Lasky and her son work at a nearby deli.
RELATED: 1 dead and 48 injured after suspected gas explosion in South Africa
"He said 'Ma, a building exploded.' I ran and looked and saw a guy climbing down the rubble. The owner of the store said there were people all over the ground," Lasky said.
Newark officials said six people were hurt. Five were taken to area hospitals. One woman suffered from serious burns.
Several injured, building decimated in Newark explosion
"I actually know the man who is in there. His name is Mario, and I just hope he is going to be OK," Lasky added.
The Red Cross is assisting at least 31 displaced families, including 28 adults and three children, as investigators try to pin down what happened.
"No, we don't have any information about where the explosion started, what unit it started from; this is an ongoing investigation," Newark Public Safety Director Fritz Frage said.