Abstract: At approximately 11:30 a.m. on November 19, 1997, employees of American Packaging Corporation complained of headaches. Kansas Power and Light was called, and a request was made by the employer for the power company to test the air quality in the production area. Screening samples for carbon monoxide revealed levels at approximately 400 ppm and the employer evacuated the building immediately. All employees, whether suffering symptoms or not, were instructed by the employer to go to the emergency room to be checked for carbon monoxide poisoning. Of the 36 employees reporting to the emergency room, 9 left without treatment, 20 were treated with oxygen as outpatients, 4 were admitted overnight, and 3 were sent to another hospital for treatment in a hyperbaric chamber. Immediately following the evacuation of the facility, the employer requested the heating system and the forklifts be inspected. The source of the carbon monoxide was determined to be a propane-powered forklift used primarily in the finishing department for moving finished boxes to the adjacent warehouse area.