BOSTON (CBS) – A Revere triple-decker is a total loss following an overnight fire, but all residents were able to safely escape.

When firefighters arrived on Thornton Street late Tuesday night, heavy flames were ripping through the building.

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Revere’s Deputy Fire Chief, Anthony Giampietro says one challenge was the layout of the neighborhood.

“This is always a tough area for us,” said Deputy Chief Giampietro. “These streets are narrow [with] a lot of cars on both sides”

Flames shoot from a Revere triple-decker. (WBZ-TV)

The fire has since been knocked down, but about 20 people were displaced including children. The building is a total loss.

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“I was just able to grab my daughter and run out of the door,” resident Norma Mendoza said.

A fire on Thornton Street in Revere. (WBZ-TV)

Danny Galvez, a neighbor who lives across the street watched from his balcony. “It was just a lot of fire coming out of the building,” said Galvez.

From inside the house, Mendoza says things were even more intense.

“As soon as I opened my door, I couldn’t see anything because the house was completely filled with smoke,” she says.

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The cause of the fire is not yet known. It appears the flames started in the rear of the building, possibly in the basement.