Abstract: Employees #1 through #6 were working in the production area at a hand tool manufacturing facility performing assembly and packing operations. All six employees experienced headaches, dizziness, vomiting, collapse, loss of consciousness, and respiratory distress. At least one forklift, and probably two (Caterpiller Model Number T30D) were running in the area to deliver and remove materials. The day of incident was the first cold day since the facility was opened in June, and the doors and fans in adjacent areas were not all open for ventilation. No exhaust and no make up air were provided in production areas ventilation system. All the employees were hospitalized and their carboxy-hemoglobin levels in the blood confirmed CO overexposure.