At least seven workers were injured in a fire which erupted at a plywood plant in the U.S. state of Texas Saturday, local media reported. The blaze began shortly after 18:15 local time (2315 GMT) at the Georgia-Pacific plant in Corrigan, about 160 km north of Houston, The Houston Chronicle reported. At least four workers were airlifted to a medical center in Houston, while three others were taken by ambulance to an area hospital, according to the report. Other media reports said four victims were airlifted to hospitals while as many as five others were taken to hospitals by ground ambulance. The number of victims cannot be verified immediately. Firefighters have extinguished the blaze. It's not clear what caused that fire. Some firefighters told the media there was a problem with a sawdust collection system and the dust caught fire. The Georgia-Pacific plant manufactures plywood and flooring products. The company released a statement late Saturday, saying "our thoughts and prayers are with the victims and their families." The company also said the plant's operations will be shut down for an undetermined amount of time