Updated 11/13/11 – 4:58 p.m.

CHICAGO (CBS) — A house was flattened in an explosion early Sunday morning in the West Lawn neighborhood on the Southwest Side and two people were critically hurt.

CBS 2’s Vince Gerasole reports it happened around 6:45 a.m. Sunday at 6659 S. Keating Av. Three people were inside the house at the time. All three suffered burns in the explosion and fire.

The married couple who lives there – Pedro and Oyola Sepulveda – was critically injured. The third person inside the home took himself to a hospital, but the extent of his injuries was unknown.

“I thought it was a plane, cause a huge explosion and all I could see was just tons of debris coming down from across the street,” neighbor Rudy Venegas said.

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Crews were still probing what was left of a small bungalow hours after the early morning explosion.

It completely leveled the Sepulveda home, damaging the houses on either side. Across the street Venegas said he saw his neighbor, Pedro Sepulveda, running for safety, engulfed by flames.

“His hair was on fire his clothes were on fire,” Venegas said. “I never saw the wife. Him, he was bad off, he was all bloody.”

Neighbor Doreetha Wheatley said, “We noticed the house next door had completely collapsed and the neighbor was crying for help.”

Wheatley said that, in the pre-dawn hours, smoke and a gassy smell filled the street.

The force of the explosion shattered her windows and debris blocked her family’s front door. They escaped to safety through a window.

“We didn’t know if our house was going to explode. It looked as if it was going to catch fire,” Wheatley said.

Peoples Gas crews joined police and fire units to secure the area and look for a cause, turning off gas in a three block area, as they went house to house to search for any possible leaks

“Anytime something like this happens, you know, everybody kind of gets on edge. But we want them to know that they are safe,” Peoples Gas spokeswoman Bonnie Johnson said.

Local residents rescued the Sepulveda’s next-door neighbor, Rosalinda Delgado, who is in her 80’s.

“I grabbed the old lady and brought her in my house,” Venegas said.

Delgado’s frightened son said she was hospitalized for smoke inhalation, but will be fine.

“I am worried about my mom, but thank God, the Lord, she’s okay,” Rene Delgado said.

The families on either side of the Sepulvedas were displaced due to damage from the explosion.

Gas service to the area remained shut off as of 5 p.m. Sunday.

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