Abstract: On August 14, 2012, four employees, with J Lohr Vineyards & Wines, were operating gas forklifts in a barrel room with limited ventilation. The barrel room stored wine, and all four employees used and stored gas forklifts inside the barrel room with the doors closed. Doors were generally kept closed to keep wine cool. Limited ventilation allowed carbon monoxide levels to increase and exceed the ceiling limit causing illnesses among four employees. All four employees were overcome by carbon monoxide, and all suffered symptoms of overexposure to varying degrees. One employee suffered serious illness and lingering effects.