Abstract: Three untrained employees were assigned to install seven gas cylinders containing carbon dioxide in a fixed extinguishing system. After they installed six cylinders, one of the employees connected the control head on the second cylinder's valve. He did not know that the system needed to be in set position before the cylinder valve was connected. When the employee connected the control head, he caused a sudden activation of the system and the release of carbon dioxide into the room. While trying to escape, he injured his head. He required 12 sutures and was hospitalized for his injury. A second employee sustained contusions to his chest and right knee.