Abstract: Employee #1 and three coworkers were preparing to shut down a hydropulper in order to conduct internal maintenance. Before that could be done, the hydropulper needed to be drained, and Employee #1 discovered that the drain pipe was blocked. He attempted to loosen the plug by climbing down a fixed ladder into a 5 1/2 ft deep sump pit, standing on the drain pipe, and attaching a water hose to the drain pipe. He climbed out of the pit and turned on the water. When the water did not work, he climbed into the pit again, stood at the bottom of the pit, and forced a bent pipe into the drain in an attempt to loosen the plug. Meanwhile, a switch controlling two water sources had been turned off on the control panel by changing it from automatic to manual; this was supposed to cut off water flow into the hydropulper. The control had been modified 5 to 6 months earlier but the changes had not been communicated to employees authorized to use the equipment or to those affected by the change. Water continued to flow into the hydropulper and an additional problem was created by the fact that the control panel operator's visual contact with the hydropulper was obstructed following the switch from auto to manual. Consequently, while Employee #1 was in the pit, the hydropulper overflowed pulp stock material at 130 to 150 degrees Fahrenheit, which struck his back, shoulders, and arms. When a coworker could not pull him out of the pit, Employee #1 was subsequently struck by two more waves of the material over the course of 2 to 3 minutes before he could pull himself out of the pit using the fixed ladder. Employee #1 suffered first- and second-degree burns to approximately 40 percent of his body (the upper portion but not his face). Employee #1 recovered without complications or skin grafts and was released to finish rehabilitation and therapy at home.