Abstract: On October 1, 2012, Employee #1, a 21-year-old male with Archstone Communities LLC., was working as a Porter-Ground Keeper at an apartment building. Employee #1 had been using a Porter-Cable, PCH 3500C, a gas-powered pressure washer, to clean outdoor and smaller trash rooms. In the afternoon, Employee #1 had started cleaning a much larger trash room located in the underground garage. Employee #1 brought the machine inside the L-shaped room to wash the back wall of the room. The temperature was unusually hot for San Francisco (with a max temp of 86 degrees Fahrenheit) and Employee #1 was wearing waterproof gear at the time. After approximately 1.5 hours, Employee #1 started sweating profusely and became dizzy. Employee #1 was transferred to hospital by paramedic on 100-percent oxygen since he was suspected of carbon monoxide exposure which was later confirmed at the hospital. Employee #1 was placed on high flow 100-percent oxygen for additional two hours and received medication for his headache and nausea. Employee #1 was discharged after a few hours. The cause of the illness was the use of the gas-powered pressure washer in a poorly ventilated area which resulted in the Employee's exposure to carbon monoxide from its exhaust. The Employer was cited for failure to provide proper training on safe operation of the equipment prior to its use. Employee #1 had worked on the site for approximately nine months. Employee #1 started working there for six months through a Temporary Agency before being hired by the Building property management company, Archstone Communities LLC, three months prior to the incident.