Abstract: On January 2, 2002, Employee #1, working for Clarko, was removing oil from a vertical cylindrical skimmer tank. Problems with a treater caused the level of oil in the skimmer tank to rise above its normal level. The treater is where the petroleum that flows from the oil well is heated and the brine and oil are separated. The brine from the treater goes to the skimmer tank where the remaining oil is separated from the water. The upset that occurred during the weekend allowed more oil than normal to flow to the skimmer tank. Because of the high volume of oil in the skimmer tank, it was necessary to withdraw the oil from the tank. Employee #1 was pulling a three inch vacuum hose out of the skimmer tank while sitting on top of the tank, when he fell into the tank containing oil, brine, and other liquids and drowned. The hole on top of the tank used to put the vacuum hose through, was an opening caused by the corrosion and deterioration of the tank and was not there by design.