CAMBRIDGE (CBS) — A two-family home in Cambridge was significantly damaged by an early morning blaze Sunday.

Firefighters were called to the house on Van Norden Street around 6:16 a.m. They were met with heavy smoke.

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Three people were able to make it out safely. One dog was rescued and given oxygen, another dog did not make it out alive, the fire department said.

Firefighters tend to a dog rescued from a fire in Cambridge Sunday morning (Photo Courtesy: Cambridge Fire Dept. Twitter)

Firefighter Gerard Mahoney was on the scene. He said the flames were difficult to fight because of the storage and hoarding-like conditions on the first floor where the fire started.

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The fire also moved into the walls of the first, second, and third floors of the home.

“Obviously it’s very tough, you don’t want to see anybody have a fire in the place where they live, but [it’s] especially tough this time of year with the holidays,” Mahoney added.

The cause of the fire is under investigation.

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One firefighter was treated for smoke inhalation but no other injuries were reported.