The accident occurred when a steel beam was to be installed in the new saw house.
"There is a person who has been injured by a beam that fell down and hit the person in the back," says CEO Lars-Erik Klas.
The injuries are considered serious but should not be life-threatening.
"We don't know much more about the cause, we have started an investigation that we hope will be completed tomorrow. Then we'll probably know more.
The injured person was hired by a subcontractor.
"Those who saw this were mainly colleagues of the contractor. That employer has organised crisis support for its employees," says Lars-Erik Klas.
The accident has been reported to the Swedish Work Environment Authority and the police have carried out an investigation at the workplace.