An early Monday morning fire ripped through an apartment building in Williamsburg, Brooklyn, leaving five people, including three firefighters, hurt. 

Many were able to escape the blaze on Humboldt Street, thanks to two neighbors who stepped up as soon as they saw the billowing black smoke. 

Neighbors frantically knock on doors

The four-alarm fire started on the first floor of 494 Humbolt just before 2 a.m., shortly before Bentley Robles and Ronan Counihan jumped into action to alert their neighbors. 

Without skipping a beat, the pair called 911 as they banged on doors to wake everyone up.   

"I literally am knocking on people's doors, being like, 'Emergency! Fire!'" Robles said. "There are flames that are just ... like, tidal waving up."

"We were in bed. Our neighbor came, ringing our door frantically, he woke us up. We smelled smoke, popped my head outside, flames shooting out of his building," one resident said.

FDNY on scene in minutes

Firefighters arrived on the scene in less than four minutes and immediately started tackling the blaze. But the building, primarily made of wood, served up an unexpected obstacle for them.

"It's very labor-intensive. The fire gets into the voids of these very old structures. So we have to open up the walls, the ceilings, the floors, manually," FDNY Chief of Operations Kevin Woods said. 

The fire quickly spread to two neighboring buildings, and grew to four alarms. Both 494 and 496 Humboldt St. were issued full vacate orders due to the extensive property damage. 

"Everything's gone," a tenant said.   

A miracle there were no fatalities, neighbors say

Robles and Counihan said it was like a Christmas miracle that everyone and their pets made it out alive. 

"I have three dogs. So I'm just, like, the fact that no animals were hurt in this, along with people, it is a miracle," Counihan said. 

Three firefighters suffered minor injuries and two residents were treated for minor burns. 

The American Red Cross said it was assisting six adults with services. A total of three households were impacted by the fire. 

The cause of the blaze is under investigation.