At 7:30 a.m. on 8/18/19, a maintenance employee was removing bolts from the bearing housing of a mixer using a break-over bar with a socket. He was standing inside the mixer panel on a flat surface with the break-over bar at chest height lifting upwards when he felt a sharp pain in his back and his knees became weak. He then laid down on his back. He suffered a compression fracture on his L7 vertebra.