Abstract: On September 19, 2001, Employee #1, a vacuum truck driver, died while cleaning the inside of a vacuum tank. The company, Advanced Pressure System, is primarily engaged in industrial and commercial cleaning. The services provided to their customers are as follows: oil well and cellar cleaning; pump unit cleaning and painting; vacuum truck services; steam cleaning; high pressure washing; oil spill cleaning and emergency response services. The accident happened off-site at an oil derrick. On the day of the accident on September 19, 2001, at around 3:00 p.m., Employee #1 was last seen washing the inside of his vacuum truck, using a 0.85-inch garden hose fitted with a spray nozzle, from the top hatch opening. This vacuum tank of the truck was used to pump out oil and water from cellars and into the waste water tank. At about 3:30 p.m., Employee #1 was found lying on his back unconscious inside the vacuum tank with his head near the back hatch opening. Local paramedics were called in at 3:31 p.m. Employee #1 had no sign of trauma but had a heavy smell of oil, and paramedics observed some oil stain on the insides of the tank. Cardiopulmonary resuscitation and other emergency medical services were rendered. Employee #1 was then transported to Century Park East Hospital, where Employee #1 was pronounced dead at 4:30 p.m. According to the coroner, the actual cause of the death was undetermined.