A natural gas explosion destroyed a duplex in Lewisville, Texas, several hours after construction workers mistakenly cut a gas line. 

The duplex behind the Lighthouse Pentecostal Church of God is owned by the Christian Community Actions, an organization that assists people who are in need.

The home exploded at 12:30 p.m., while crews were working to repair a gas leak. Construction workers mistakenly cut a 4-inch gas line in the area at about 10 a.m., investigators said.

Emergency crews at the time said they had the issue under control and that no evacuations were necessary. But fire officials later said that they had evacuated a block downwind of the gas leak.

The house that exploded was not included in the evacuations.

Cause of blast being investigated
Atmos Energy said the cause of the explosion is under investigation.

Two Lewisville firefighters and a man who was inside the duplex at the time of the explosion were sent to area hospitals after the explosion, according to fire officials.

The man who was inside the duplex was critically injured and taken to Medical Center of Lewisville. He underwent surgery and was later airlifted to Medical Center of Plano, where he was in intensive care Friday night. He is expected to survive.

The injured firefighters were released from the hospital Friday.

Witnesses said the explosion "felt like a bomb went off" and said they could feel the shock wave from blocks away.

"Honestly, I didn't see anything at first," said Danny Vigil, who lives in the area. "What I felt was a huge explosion. It was almost as if you were sitting in a movie, a big action movie -- you hear bombs going, that’s what it sounded like."

"Pictures were rattling, falling onto the ground," he said. "The first thing I did was run out the front door -- ran all around because I thought some car hit our home. [I] ran to the back, I saw flames, smoke, debris in the air, shingles, branches. It was just an unbelievable sight.”

"I was sitting at my desk whenever was a loud explosion," Dwayne Ryaman said. "[I] literally thought maybe an 18-wheeler had ran into my building at first."

“When I came out of my door, I immediately saw the black smoke and flames," he said. "I got a little bit closer to the scene, saw the debris that was strewn out in the middle of the street."

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Debris covered the roadway in the 500 block of East Main Street in Lewisville. The road was shut down while emergency crews worked near the scene.

None of the surrounding homes or businesses were damaged in the explosion.

NBC 5's Ellen Goldberg and Amanda Guerra contributed to this report.