The explosion at the Indiana Laminate plant occurred when a board became stuck inside a machine, caused a spark and triggered the explosion, Fire Chief Kenny Hochgesang said.
"We have several walls that have collapsed," Hochgesang said.
The explosion also caused a fire in a dust-collection system outside the plant, but it was extinguished in 40 minutes, Hochgesang said.
At least six of those hurt were working in the immediate area of the explosion, Hochgesang said. The plant employs about 60 people, but not all were believed to be there at the time.
The explosion occurred about 7:15 a.m. Workers built dikes to contain the water runoff to mitigate any environmental threats, Hochgesang said.
Officials of Indiana Furniture Industries, which owns the plant, did not immediately return messages.
Jasper is about 50 miles northeast of Evansville.
