Abstract: At approximately 6:20 a.m. on February 15, 2007, an employee, a security guard for Hanna Maria Construction was found dead. The employee was transported to the San Diego Medical Examiner's office. The accident occurred inside a mobile trailer measuring about 27 feet long, 8 ft wide and 8 ft high. It was manufactured by Rosewood Enterprises (serial number R-463-828) and had two rooms. One room measured 9.98 ft by 7.25 ft, had two windows, and contained a small 2300-watt gasoline generator. (The ID sticker on electric ignition said "UST OHV 5.5 58679 123456789101112"). The generator was distributed by International Merchandising Service under the name UST, manufactured by Wennling Jennseng. The other room measured 17.03 ft by 7.25 ft and contained three windows and a blue sitting chair where the employee was found, along miscellaneous construction material and tools. The rooms were divided by a thin partition with a door. When open, the door left a space 2.67 ft wide and 6.70 ft tall. The door that separated the generator and the employee had a gap between the floor and door bottom of 1.125 in. This space was blocked with a makeshift seal, a block of wood with insulation, loosely covering the 32-in. by 1.125-in. gap. It had become a common practice to run the generator inside the trailer because the neighbors had complained of the noise. The failure to provide adequate ventilation and the placement of the generator inside the trailer were the contributing factors in this accident. Introduction of an internal combustible engine into the work area lead to an employee's overexposure of carbon monoxide.