CAMBRIDGE (CBS) — Firefighters in Cambridge spent Monday morning battling flames at a duplex on Putnam Avenue. One man who lives there credits his neighbor for the safe exit.

Twenty-four-year-old Gary Ludorf has lived in one of the house’s four units for about a year and a half. “A neighbor was nearby, saw smoke coming out of our house, she came and knocked on all of our doors. She is the reason we all got out on time,” he explained.

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She also called 911, Ludorf said.

Cambridge firefighters responded to a fire on Putnam Avenue Monday morning (WBZ-TV)

According to Acting Fire Chief Gerry Mahoney, that 911 call came in around 7:50 a.m.

All residents have been accounted for and none of them were injured. One firefighter was taken to the hospital after he slipped coming down the stairs, but he is expected to be okay.

The Cambridge Fire Department said at one point, six engines, four ladders, two squads, and one rescue crew were all working at the scene.

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“Some challenges were getting to the scene of the fire because [it is] an old wood-frame building, a lot of void spaces, you have to open up ceilings and walls to trace the fire and so forth,” said Mahoney. “We think the fire may have started on the second floor rear and traveled up the wall into the third-floor area.”

It took about an hour to knock the fire down, the department tweeted.

Mahoney believes residents who lived on the right side of the house may be able to return Monday afternoon to gather some possessions. He said the left-hand side will be “uninhabitable for quite some time,” though.

Cambridge firefighters tackled a fire on Putnam Avenue (WBZ-TV)

James Cronin lives across the street and witnessed the action. “I was having a cup of coffee and I saw a fire engine pull up and curiosity, I come out to see if everything was okay and then I saw smoke coming out the building across the street.”

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He praised the fire department for their efforts. “It’s cold, it’s a little breezy, but they did it. They show up with lots of equipment and lots of people and they take care of it. They do their jobs spectacularly,” said Cronin.