Sixteen people, including three children, were left homeless after a fire raged through their East Boston homes Sunday afternoon.

When fire crews arrived to 330 Chelsea St. about 2 p.m., there was heavy fire showing and flames coming out of the top floor windows.

About 160 firefighters went to work on the flames, pouring massive amounts of water on the three-story brick duplex.

“Many, many deck guns and hand lines in use,” the fire department said on its Twitter feed.

As the fire continued to rip through the building, fire crews were ordered off of the roof and outside.

Shortly after the roof collapsed. Fire officials were worried about the structure and established a collapse zone around the building.

They were also worried about the fire spreading because of the close proximity of homes in the neighborhood. The closest door was 4 feet away, fire officials said.

The flames managed to spread past a fire wall and into the other side of the duplex.

Families on either side of the duplex were left homeless. Some families weren’t home and those who were home were checked out by emergency technicians.

There were no reports of serious injuries. However, one firefighter was treated for an injured shoulder and a resident was treated for anxiety.

Fire officials estimated damage at $2.5 million.

Danger of collapse

The intense flames caused part of the roof to collapse as fire crews worked to fight the blaze.

Besides the roof, part of the front of the building also collapsed — sending bricks crashing down on to the sidewalk below.

Building inspectors were expected to arrive at the scene and look over the damage to the building. It was unclear whether or not the top floor would have to be knocked down for safety reasons.