The explosion occurred at about 6:15pm, along Industrial Road, about a mile or two from a major highway. It took crews about two hours to put out the fire.
Eric Abercrombie with Georgia-Pacific said four employees were airlifted to Memorial Hermann Hospital, suffering mostly from serious but non-life threatening burns. Three other victims were taken by ambulance to a hospital in Lufkin. One of those was soon treated and released.
The cause of the explosion is not yet known.
This Georgia-Pacific plant manufactures plywood and flooring products.
Corrigan is a small town of about 1,600 residents.