Eleven people were injured, one seriously, in a plant explosion in southern Texas, the third blast at a Texas industrial facility this year.

It appeared that no toxic materials had been released into the air after Thursday's explosion at a plastics plant owned by Formosa Plastics Corp. USA (search).

Nine of the injured were treated and released from hospitals, but one victim was in serious condition with burns. Another person was listed in fair condition.

Formosa spokesman Rob Thibault said the plant uses many flammable materials in manufacturing PVC (search) and vinyl for floor and wall coverings. He said the factory, which employs about 1,000 people, had been evacuated.

An explosion in March at BP's Texas City refinery killed 15 and injured 170 people. And BP's refinery exploded a second time in July, but resulted in no injuries. The company was recently fined $21 million for the March explosion.

Calhoun County Justice of the Peace Gary Noska (search) said he was at City Hall when he heard Thursday's blast.

"It was actually two explosions, a smaller one and second one a lot louder and bigger, and then a few smaller ones after that," he said. "It was some major damage."

Point Comfort, on the Texas coast, is 150 miles southeast of San Antonio.