Abstract: At 3:30 p.m. on January 17, 2017, Employee #1 and his coworkers were cleaning the inside of an asphalt tank using a hyrdroblast nozzle that was attached to a metal arm constructed from steel tubing. The arm was placed over a permanently-fixed metal pole inside the tank and was rotated at 180 degrees along the height of the tank to remove asphalt that had solidified on the walls. The arm was moved horizontally by the force of the water and two coworkers inside the tank using guide ropes to move the arm across the face of the wall interior. The arm moved vertically up the height of the tank by means of a hand-operated winch located outside the tank and affixed to the arm by means of a wire rope. A coworker on the exterior of the tank hoisted the arm by slowly winching the wire rope back onto the spindle of the hoist. The water and asphalt debris were removed from the tank floor using a nozzle attached to a vacuum truck. The employee and coworkers reportedly stood on the opposite side of the 180 degree radius of the hydroblast arm but the wire rope broke and the arm struck Employee #1 on the head. Visibility in the tank prevented the coworkers in the tank from actually witnessing what had happened but it was speculated that Employee #1 had moved under the arm in an attempt to keep it from falling. The employee was hospitalized.