Fire crews battled a 4-alarm blaze Wednesday afternoon in South Boston.
The fire broke out around 5:20 p.m. on E. 7th Street, according to the Boston Fire Department.
Heavy flames could be seen coming through the roof of the two-and-a-half-story duplex.
In-depth news coverage of the Greater Boston Area.
"We just heard people screaming, so we looked out the door and we could see the reflection of the flames in the windows across the street," said Geoffrey Spooner, who recorded video.
the fire broke out on the left-hand side of a duplex, which was under construction and vacant at the time.
It spread next-door, where a family of seven, including a child, lives. That family is now without a home.
The layout was difficult for firefighters, as the building is on top of a huge hill, where homes are tightly packed.
"It's a building under construction, so there's no plaster on the walls, so the fire started in the basement area and quickly went up throughout the building," Boston Fire Deputy Chief Jack Dempsey said.
The fire department tweeted after 6 p.m. that the heavy fire had been knocked down.
Two firefighters sustained minor injuries, one suffering from heat exhaustion and another having a laceration.