UPDATED 05/30/12 10:48 a.m.

VILLA PARK, Ill. (CBS) — The Villa Park Fire Department now says foam soundproofing, not gunpowder, was the likely cause of a fire last night at VFW Post 2801 while a bingo game was going on in an upstairs room.

WBBM Newsradio’s Bernie Tafoya reports the fire began around 6:30 p.m. in the basement gun range at the VFW Hall, near St. Charles Road and Ardmore Avenue, at as welders were doing spot-welding on a metal backstop, according to Fire Investigations Unit Lt. Mike Barton.

LISTEN: WBBM Newsradio’s Bernie Tafoya reports

Barton says the welders didn’t realize there was highly flammable foam soundproofing insulation behind the backstop and all over the ceiling and walls.

“While they were doing the spot-welding, the foam that was behind that backstop wall – the welder did not realize that there was foam back there, and started the foam on fire,” Barton said.

As soon as one of their torches set off the fire, the welders attempted to put it out with extinguishers, but the fire grew too fast and so the welders ran and closed the door as they left the gun range, according to interim fire chief Steve Stapleton.

Seconds later, he says, “there was either a backdraft, smoke explosion, flashover, that just exploded out of that room and the easiest path to go was right up that main stairwell.”

Chief Stapleton says most of the people burned had been in that main stairwell.

Post Commander Dennis Guiseman says that, of the nine people who were taken to hospitals with burns and or smoke inhalation, four of them are still hospitalized and were doing better Wednesday.

Guiseman says all four are post staffers who helped make sure everyone escaped.

Guiseman has already been in contact with the post’s insurance company and work has already begun to clean up and restore the building. He’s hoping to have the post open again in about two months.

“We get a restoration company in here, we start the cleanup, and we get ourselves back up and running,” he said.

But for now, there will be no bingo on Tuesday or fish fries on Fridays at the VFW hall.

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