By CBS3 Staff

PHILADELPHIA (CBS) — In Chinatown, an early morning two-alarm fire tore through a building and now investigators are trying to figure out the cause. The fire broke out in the area of 10th and Race Streets just before 2 a.m. Tuesday, forcing an evacuation of the building.

About 25 residents were displaced by the fire. Even though the fire is out, firefighters spent hours using a ladder truck to pour water on the roof to make sure the fire wouldn’t flare up again.

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In the heart of Chinatown, several blocks were shut down for most of the day after the building fire.

Chopper 3 shows the roof burning as heavy smoke poured into the air.

“We didn’t know what was going on,” resident Kathy Nguyen said. “We went in the back and that’s where we see all the flames coming, we just don’t know where it’s coming from.”

Heavy flames and smoke could be seen spilling from the building. Fire crews spent hours battling this stubborn blaze and were able to place it under control around 6:13 a.m. The flames quickly began to spread, impacting the two adjacent buildings, which include several businesses.

At one point, there was so much heavy smoke it was difficult to see down the street.

“We call this surround and drown,” Captain Derek Bowmer said. “This is an exterior attack, that’s what we call it. So we have massive stream devices just putting water on it. What you don’t see is in the rear, we are doing the same things. So we just have it surrounded. We will just continue to put water on it.”

There were a lot of firefighters on the ground and fire crews moved fire engines out of the way in case of a building collapse.

“That’s just a precaution,” Bowmer said. “With such a heavy fire load and it’s burning so long, for so many hours, we just want to establish this collapse zone. That’s normally what we do when we come on these long, extended operations.”

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More than a dozen businesses had to close as a result of the fire. Businesses around the corner where the road was blocked off were affected as well.

“This is lunch time, supposed to be fully packed, and now we have nobody. So it’s like, nobody can be able to work. No pickup service. So we got severely impacted by the fire,” said Clement Ho, owner of Cily Chicken Rice.

There are a lot of businesses in Chinatown. The businesses are usually on the lower floors of the building and the upper floors are residential units. CBS3 is told a lot of people were asked to evacuate around 2 a.m.

Kathy, Jonathan, and their cat Frankie, quickly evacuated their home as the flames took over three nearby buildings.

“Somebody came knocking on the door around 2 in the morning, we didn’t know what it was at first,” neighbor Jonathan Williams said. “Then we get up, open the door and they’re like OK, the fire alarm went off. We got to get out of here. We went down the fire escape and we started to see all of these embers coming off the building to our right. I think we got to move down a little further. Then we walk around to the other side and we just saw that the whole building was just, you know, engulfed in flames.”

A portion of the roof caved in, while firefighters were dousing the flames from the outside.

Neighbors who gathered to watch consider themselves lucky and fortunate, but business owners in this bustling part of the city like Skylar Pratt are worried.

“It’s something to see because you come out there’s black smoke and you can see the flames going up, there’s ash, it’s concerning,” Pratt said.

One firefighter was taken to the hospital with a minor injury. Investigators are still working to determine the cause of the fire.

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CBS3’s Waskisha Bailey and Madeleine Wright contributed to this report.