Abstract: On January 19, 2005, Employee #1 and a coworker, Employee #2, of Safety-Kleen, Inc., were attempting to pump used motor oil residue from the bottom of a tank truck and transfer it to a rail car. They did not make a confined space entry during this procedure. When they were unable to remove the residue because of its viscosity, they stopped what they were doing to discuss, along with a third employee, Employee #3, other ways of removing the residue. Employee #1 made a noise and a movement, going backward and then pitching forward, ultimately striking his head on a truck bumper and falling to the ground. Medical information obtained during the investigation indicated that the cause of death was a heart attack. An autopsy was not performed. Lab analysis of the contents of the oil residue in the tank truck was consistent with the company records of the type of waste material picked up by the driver on his rounds.