PA- An explosion rocked a Philadelphia neighborhood Thursday afternoon, blasting the front off a row home.

Investigators are still trying to figure out what caused the explosion, but said natural gas could be to blame.

Splintered wood, shattered glass and bricks plunged onto Sixth Street and all over the surrounding area.

Firefighters took to neighboring rooftops to battle the raging fire that resulted in the Queen Village neighborhood of Philadelphia. Nearby homes were evacuated.

Witnesses said they heard a loud “boom.” The front of the house came crumbling down, and then came the fire.

The explosion, reported about 3:52 p.m. on the 700 block of South Sixth Street, destroyed a million-dollar home in an instant, NBC 10’s Justin Pizzi reported.

There were no reports of injuries or anyone trapped.

“I said, ‘What the heck is going on?'” said one neighbor, William Smith, who said he lived just behind the house that exploded. “I was on the couch, and it moved me.”

Firefighters were at Sixth and Bainbridge streets minutes later. They said no one was in the home where witnesses said there was an explosion. People in homes on both sides of the property were able to get out safely.

The homeowners were at the scene by 5 p.m., Pizzi reported.

The entire facade of the three-story house was in the street when fire crews arrived.

Utility crews shut off power and gas to the surrounding homes as a precaution. Several houses on the block were evacuated.

Firefighters declared the blaze under control at 4:39 p.m. but battled flames and smoke pouring from the structure for more than two hours.

Delivery driver Roy Dillon described what he heard and saw as he rounded the corner at Sixth and Bainbridge streets Thursday afternoon.

“As I get toward the intersection, I heard like a whistle. I happened to just glance at my right. And the next thing I know, I hear a ‘ba-boom.’ And, I don’t know if it’s a garage window, but it just came out. It went across the street, and the whole house just collapsed,” witness Roy Dillon said.

Neighbor John Egan, who was out on Sixth Street at the time, called it “the loudest explosion.”

“The whole ground shook, and all you knew was … the whole house was blown out into the street — like glass, everything. There were no walls left. The whole place just rocked and blew the whole building out into the street,” Egan said.

The homes on either side were not damaged, NBC 10 News reported. Their homes actually withstood the blast as well, but now their issue is water damage — firefighters dropped a lot of water on the entire row of houses.

“It was dirt all over the steps, and on the second floor, the ceiling was down,” said Melissa Antley, who was allowed to enter her house.

Antley will stay with friends while her house is being worked on.

“It was pretty disturbing,” Antley said. “The whole house just blew out.”

Another neighbor told NBC 10 that he saw the windows explode. A frame flew over the home behind the exploding property and landed in the street.

Chopper 10 showed what appeared to be a window on the roof of another building there, as well as other debris scattered about.

Sixth Street was closed between Lombard and Fitzwater streets. Bainbridge Street was closed between Seventh and Sixth. And Kater Street was closed at Sixth Street.

Peco Energy Co., Philadelphia Gas Works and the city’s Department of Licensing and Inspections were called to the scene.

“As you can tell, we still have some major work to do in terms of extinguishing the fire and L&I making an assessment of the property to see how stable it is. And then, at that point, we’ll make a determination on when it’s safe for people to return to their homes,” said Philadelphia Fire Department Executive Chief Jason Williams.

Firefighters said it was extremely lucky that no one was injured.

Fire marshals were at the scene trying to figure out what caused the explosion.

The American Red Cross said at least eight people who live on the block were displaced.