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WHITEHALL (KDKA) — The owner of a Bethel Park flooring company was among the three contractors injured in a violent and unusual explosion at a Whitehall home Wednesday night.

All three men working on a job in the basement of a home in a residential neighborhood remain at Mercy Hospital with severe burns, two are in critical condition. Melted shoes and tattered clothes remain visible, evidence of the violent explosion that rocked this Whitehall home and sent neighbors running to help the injured.

One of the victims working for Sims Speciality Flooring of Bethel Park has been identified. The company’s president, David Sims, was severely burned while working in the basement of the home. The two other men have yet to be identified.

Around 7:30 Wednesday night three contractors from the flooring company were severely burned while working in a home on the 4300 block of McKee Drive. Homeowners Albert and Machelle DeCarlo, were remodeling their basement according to neighbors.

Watch Meghan Schiller’s Report:

“The worst part was the blood-curdling screams. Burn victims sustain so much pain,” said Ashley Sites, registered nurse and neighbor.

whitehall house explosion 3 Severely Burned In Whitehall Explosion

(Photo Credit: Meghan Schiller/KDKA)

Sites said she heard a loud boom and didn’t think anything of it. Then she heard screaming and walked outside to see the three workers screaming a few doors down. She quickly sprang into action.

“I had said ‘Well, we need to preserve as much skin as we can, we need to wash the chemicals off,’” Sites said. “I couldn’t touch them, I didn’t have gloves on, so we got towels. We were able to use that as a barrier, put that around them to keep the skin moist, wash the chemicals off.”

Firefighters and EMS arrived within minutes and transported the victims to UPMC Mercy’s burn unit.

Neighbors and firefighters told KDKA it appeared that the workers were preparing to stain the concrete floor in the home’s basement. The fumes from the chemicals ignited in some way and turned into a fire ball that burst out of the home.

“It was definitely an experience and probably a life-changing moment for a lot of us,” Carllie Reck, a next-door neighbor, said.

Reck said the boom shook her wall-mounted television. One of the victims ran to her front door.

“When he was at my door, his face was stark white and his eyes weren’t really open. You could see holes in his shirt,” Reck said.

whitehall explosion flammable 3 Severely Burned In Whitehall Explosion

(Photo Credit: Meghan Schiller/KDKA)

The flooring materials still sat in the backyard on Thursday, marked “flammable.” The door rests on the driveway, charred around the edges. The windows to the basement also appear black around the edges.

The Whitehall Fire Department said the residents on the second floor were not hurt.