McKINNEY — Three people were taken to Parkland Memorial Hospital in Dallas after a gas line exploded in a McKinney neighborhood Friday evening, city officials said.

Two houses in the 600 block of Fenet Street were destroyed by the blast, which occurred about 5:50 p.m., said McKinney police Capt. Randy Roland. A third home was damaged in the explosion, officials said.

McKinney Fire Chief Mark Wallace said the homes were engulfed in flames when crews arrived.

Firefighters began working to remove those injured and then took a defensive stance against the blazes. He said the three people were seriously injured in the explosions.

Chief Wallace said workers, who were not among those injured, were boring underground along Throckmorton Street just north of Fenet when they struck the gas line. Gas apparently went into the homes and then ignited, he said.

“The gas follows the path of least resistance,” he said, adding that it probably followed the gas lines and got into the homes from underground.

Earl Avery, a Richardson resident, said he was visiting relatives in McKinney Friday and could smell gas in the neighborhood for about a half hour before the explosions occurred.

“You could feel the ground shaking and feel the compression in the air,” he said.

An official with Atmos Energy said a gas contractor was responsible for the explosion.

“The theory at this point is the gas got into the sewer, and from the sewer, it went into the homes,” said Rand LaVonn, a company spokesman. “The gas is now turned off, at about 7:30 [p.m.], and we’re working as quickly as possible to get it out of the sewer so people can return to their homes.”

Isabel Flores and his 16-year-old son, Johnathan, had stepped outside their east McKinney house Friday about 6 p.m. when the ground shook and an explosion rang out.

Seconds later, there was a second roaring explosion.

Both Mr. Flores and his son looked down Throckmorton Street toward Nancy Foster’s house and saw flames. So they took off running in that direction and were later joined by Robert Wiggins.

“The house was on fire. So I hollered for Miss Nancy. I called two or three times, then ran around back,” said Mr. Flores, 57.

“I seen her and a man,” who neighbors said had been doing her hair, Mr. Flores said.

Mr. Wiggins said he arrived just as Ms. Foster and her friend were being helped out the remains of her house.

“I didn’t even recognize her,” said Mr. Wiggins, 53. “I’ve known her my whole life and I couldn’t tell that was Miss Nancy. I could see her skin peeling off.”

She didn’t have any hair. And she was walking with her arms and legs away from her body as if every touch hurt, Johnathan said.

A man was walking around, his left arm so badly burned that the skin was gone and they could see his muscle underneath, the men said.

After they walked Ms. Foster to an ambulance about 200 feet down the street, two more quick explosions occurred.

Mr. Flores said right before the explosions, some workers had been boring into the street with a big machine. One of the workers came up to him and asked them to call 911 because they had hit a gas line.

“He said he had called Atmos 30 minutes earlier, but they had not come. So he asked me to call 911,” Mr. Flores said.

As firefighters doused a burning home on Fenet near Throckmorton, they also sprayed the area near the boring machine to help dissipate the natural gas. Chief Wallace said that was done in an effort to keep the gas from igniting from the burning home.

Chief Wallace said 25 homes were evacuated. But it’s not clear how many people live in each house.

A shelter was set up for the displaced at First Baptist Church of McKinney on Louisiana.

Dallas Morning News staff writer Jim Getz contributed to this report.