BOSTON (CBS) – Two firefighters were injured battling a quick-moving fire at a South Boston duplex Wednesday evening.

South Boston neighbors returning from work and school became panicked as they turned onto East 7th Street to see the fast moving flames.

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“We heard screaming,” neighbor Geoffrey Spooner said. “Everybody is running up the street. We just started running toward it. I’m banging on doors and banging on windows because there’s two houses right there.”

“It was real bad,” neighbor John Walsh said. “The flames were out the second floor windows and shooting out to the street and up above.”

The fire started in the left side of the building, which is under construction. Neighbors say work crews had just left for the day.

Fire at duplex on East 7th Street in South Boston (Image credit Boston Fire)

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“The fire started in the basement area and quickly went up throughout the building because there’s nothing to contain it,” Boston Fire Chief John Dempsey said.

Six adults and a child got out safely from the other side of the building. Neighbors know it could have been much worse.

“Thank God it wasn’t windy and icy and snowy like a normal winter,” Walsh said. “If it was all snowbanks it would have been a disaster for the fire trucks. It’s on a hill.”

“It was an empty building and the people next door got out,” Spooner said. “So everybody is safe. Boston Fire Department showing up so quickly, it’s amazing how quickly they fixed this.”

One firefighter was treated for heat exhaustion and another suffered a bad cut.

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Investigators are still working to determine the cause of the fire.