It happened just after 9 p.m. at 361 Madison St.
City of Passaic Mayor Hector Lora says the fire began on the first floor, and when he arrived there was a lot of smoke.
"Police, firefighters, people were helping pull people out," he said. "Even a motorcycle club pulling hoses. Everyone was doing their best."
Pictures obtained by Eyewitness News showed firefighters trying to pull a couple -- a husband in his 60s and his wife, 50 -- out of the first floor window where the fire started.
Both of them were transported to the hospital where the wife was pronounced dead. The husband remains in critical condition. Neither have been identified yet by authorities.
"He was really nice and kind," added Passaic's Amelany Soriano. "He didn't speak much, but he's a funny person."
Authorities say three others were also rescued and suffered minor injuries.
Officials added the fire also forced residents from their homes. The Red Cross, in collaboration with the City of Passaic, has opened a temporary shelter for anyone displaced by the fire.
The building is off limits until water and fire alarm services are restored.
The cause of the fire is being investigated.
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